Adding upstream version 2:9.0.1378.upstream/2%9.0.1378upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3883 insertions, 0 deletions

diff --git a/src/if_mzsch.c b/src/if_mzsch.c
new file mode 100644
index 0000000..e4ebf29
--- /dev/null
+++ b/src/if_mzsch.c
@@ -0,0 +1,3883 @@
+/* vi:set ts=8 sts=4 sw=4 noet:
+ *
+ * MzScheme interface by Sergey Khorev <sergey.khorev@gmail.com>
+ * Based on work by Brent Fulgham <bfulgham@debian.org>
+ * (Based on lots of help from Matthew Flatt)
+ *
+ * This consists of six parts:
+ * 1. MzScheme interpreter main program
+ * 2. Routines that handle the external interface between MzScheme and
+ *    Vim.
+ * 3. MzScheme input/output handlers: writes output via [e]msg().
+ * 4. Implementation of the Vim Features for MzScheme
+ * 5. Vim Window-related Manipulation Functions.
+ * 6. Vim Buffer-related Manipulation Functions
+ *
+ * NOTES
+ * 1. Memory, allocated with scheme_malloc*, need not to be freed explicitly,
+ *    garbage collector will do it self
+ * 2. Requires at least NORMAL features. I can't imagine why one may want
+ *    to build with TINY features but with MzScheme interface.
+ * 3. I don't use K&R-style functions. Anyways, MzScheme headers are ANSI.
+ */
+
+#include "vim.h"
+
+#include "if_mzsch.h"
+
+// Only do the following when the feature is enabled.  Needed for "make
+// depend".
+#if defined(FEAT_MZSCHEME) || defined(PROTO)
+
+#ifdef PROTO
+typedef int Scheme_Object;
+typedef int Scheme_Closed_Prim;
+typedef int Scheme_Env;
+typedef int Scheme_Hash_Table;
+typedef int Scheme_Type;
+typedef int Scheme_Thread;
+typedef int Scheme_Closed_Prim;
+typedef int mzshort;
+typedef int Scheme_Prim;
+typedef int HINSTANCE;
+#endif
+
+/*
+ * scheme_register_tls_space is only available on 32-bit Windows until
+ * racket-6.3.  See
+ * http://docs.racket-lang.org/inside/im_memoryalloc.html?q=scheme_register_tls_space
+ */
+#if MZSCHEME_VERSION_MAJOR >= 500 && defined(MSWIN) \
+	&& defined(USE_THREAD_LOCAL) \
+	&& (!defined(_WIN64) || MZSCHEME_VERSION_MAJOR >= 603)
+# define HAVE_TLS_SPACE 1
+#endif
+
+/*
+ * Since version 4.x precise GC requires trampolined startup.
+ * Futures and places in version 5.x need it too.
+ */
+#if defined(MZ_PRECISE_GC) && MZSCHEME_VERSION_MAJOR >= 400 \
+    || MZSCHEME_VERSION_MAJOR >= 500 \
+	&& (defined(MZ_USE_FUTURES) || defined(MZ_USE_PLACES))
+# define TRAMPOLINED_MZVIM_STARTUP
+#endif
+
+// Base data structures
+#define SCHEME_VIMBUFFERP(obj)  SAME_TYPE(SCHEME_TYPE(obj), mz_buffer_type)
+#define SCHEME_VIMWINDOWP(obj)  SAME_TYPE(SCHEME_TYPE(obj), mz_window_type)
+
+typedef struct
+{
+    Scheme_Object   so;
+    buf_T	    *buf;
+} vim_mz_buffer;
+
+#define INVALID_BUFFER_VALUE ((buf_T *)(-1))
+
+typedef struct
+{
+    Scheme_Object   so;
+    win_T	    *win;
+} vim_mz_window;
+
+#define INVALID_WINDOW_VALUE ((win_T *)(-1))
+
+/*
+ * Prims that form MzScheme Vim interface
+ */
+typedef struct
+{
+    Scheme_Closed_Prim	*prim;
+    char	*name;
+    int		mina;	// arity information
+    int		maxa;
+} Vim_Prim;
+
+typedef struct
+{
+    char	    *name;
+    Scheme_Object   *port;
+} Port_Info;
+
+/*
+ *========================================================================
+ *  Vim-Control Commands
+ *========================================================================
+ */
+/*
+ *========================================================================
+ *  Utility functions for the vim/mzscheme interface
+ *========================================================================
+ */
+#ifdef HAVE_SANDBOX
+static Scheme_Object *sandbox_file_guard(int, Scheme_Object **);
+static Scheme_Object *sandbox_network_guard(int, Scheme_Object **);
+static void sandbox_check(void);
+#endif
+//  Buffer-related commands
+static Scheme_Object *buffer_new(buf_T *buf);
+static Scheme_Object *get_buffer_by_num(void *, int, Scheme_Object **);
+static vim_mz_buffer *get_vim_curr_buffer(void);
+
+//  Window-related commands
+static Scheme_Object *window_new(win_T *win);
+static vim_mz_window *get_vim_curr_window(void);
+
+/*
+ *========================================================================
+ *  Internal Function Prototypes
+ *========================================================================
+ */
+static int vim_error_check(void);
+static int do_mzscheme_command(exarg_T *, void *, Scheme_Closed_Prim *what);
+static int startup_mzscheme(void);
+static char *string_to_line(Scheme_Object *obj);
+#if MZSCHEME_VERSION_MAJOR >= 501
+# define OUTPUT_LEN_TYPE intptr_t
+#else
+# define OUTPUT_LEN_TYPE long
+#endif
+static void do_output(char *mesg, OUTPUT_LEN_TYPE len);
+static void do_printf(char *format, ...) ATTRIBUTE_FORMAT_PRINTF(1, 2);
+static void do_flush(void);
+static Scheme_Object *_apply_thunk_catch_exceptions(
+	Scheme_Object *, Scheme_Object **);
+static Scheme_Object *extract_exn_message(Scheme_Object *v);
+static Scheme_Object *do_eval(void *, int noargc, Scheme_Object **noargv);
+static Scheme_Object *do_load(void *, int noargc, Scheme_Object **noargv);
+static void register_vim_exn(void);
+static vim_mz_buffer *get_buffer_arg(const char *fname, int argnum,
+	int argc, Scheme_Object **argv);
+static vim_mz_window *get_window_arg(const char *fname, int argnum,
+	int argc, Scheme_Object **argv);
+static int line_in_range(linenr_T, buf_T *);
+static void check_line_range(linenr_T, buf_T *);
+static void mz_fix_cursor(int lo, int hi, int extra);
+
+static int eval_with_exn_handling(void *, Scheme_Closed_Prim *,
+	    Scheme_Object **ret);
+static void make_modules(void);
+static void init_exn_catching_apply(void);
+static int mzscheme_env_main(Scheme_Env *env, int argc, char **argv);
+static int mzscheme_init(void);
+#ifdef FEAT_EVAL
+static Scheme_Object *vim_to_mzscheme(typval_T *vim_value);
+static Scheme_Object *vim_to_mzscheme_impl(typval_T *vim_value, int depth,
+	Scheme_Hash_Table *visited);
+static int mzscheme_to_vim(Scheme_Object *obj, typval_T *tv);
+static int mzscheme_to_vim_impl(Scheme_Object *obj, typval_T *tv, int depth,
+	Scheme_Hash_Table *visited);
+static Scheme_Object *vim_funcref(void *data, int argc, Scheme_Object **argv);
+#endif
+
+#ifdef MZ_PRECISE_GC
+static int buffer_size_proc(void *obj UNUSED)
+{
+    return gcBYTES_TO_WORDS(sizeof(vim_mz_buffer));
+}
+static int buffer_mark_proc(void *obj)
+{
+    return buffer_size_proc(obj);
+}
+static int buffer_fixup_proc(void *obj)
+{
+    // apparently not needed as the object will be uncollectable while
+    // the buffer is alive
+    // vim_mz_buffer* buf = (vim_mz_buffer*) obj;
+    // buf->buf->b_mzscheme_ref = GC_fixup_self(obj);
+
+    return buffer_size_proc(obj);
+}
+static int window_size_proc(void *obj UNUSED)
+{
+    return gcBYTES_TO_WORDS(sizeof(vim_mz_window));
+}
+static int window_mark_proc(void *obj)
+{
+    return window_size_proc(obj);
+}
+static int window_fixup_proc(void *obj)
+{
+    // apparently not needed as the object will be uncollectable while
+    // the window is alive
+    // vim_mz_window* win = (vim_mz_window*) obj;
+    // win->win->w_mzscheme_ref = GC_fixup_self(obj);
+    //
+    return window_size_proc(obj);
+}
+// with precise GC, w_mzscheme_ref and b_mzscheme_ref are immobile boxes
+// containing pointers to a window/buffer
+// with conservative GC these are simply pointers
+# define WINDOW_REF(win) *(vim_mz_window **)((win)->w_mzscheme_ref)
+# define BUFFER_REF(buf) *(vim_mz_buffer **)((buf)->b_mzscheme_ref)
+#else
+# define WINDOW_REF(win) (vim_mz_window *)((win)->w_mzscheme_ref)
+# define BUFFER_REF(buf) (vim_mz_buffer *)((buf)->b_mzscheme_ref)
+#endif
+
+#if defined(DYNAMIC_MZSCHEME) || defined(PROTO)
+static Scheme_Object *dll_scheme_eof;
+static Scheme_Object *dll_scheme_false;
+static Scheme_Object *dll_scheme_void;
+static Scheme_Object *dll_scheme_null;
+static Scheme_Object *dll_scheme_true;
+
+static Scheme_Thread **dll_scheme_current_thread_ptr;
+
+static void (**dll_scheme_console_printf_ptr)(char *str, ...);
+static void (**dll_scheme_console_output_ptr)(char *str, OUTPUT_LEN_TYPE len);
+static void (**dll_scheme_notify_multithread_ptr)(int on);
+
+static void *(*dll_GC_malloc)(size_t size_in_bytes);
+static void *(*dll_GC_malloc_atomic)(size_t size_in_bytes);
+static Scheme_Env *(*dll_scheme_basic_env)(void);
+static void (*dll_scheme_check_threads)(void);
+static void (*dll_scheme_register_static)(void *ptr, long size);
+static void (*dll_scheme_set_stack_base)(void *base, int no_auto_statics);
+static void (*dll_scheme_add_global)(const char *name, Scheme_Object *val,
+	Scheme_Env *env);
+static void (*dll_scheme_add_global_symbol)(Scheme_Object *name,
+	Scheme_Object *val, Scheme_Env *env);
+static Scheme_Object *(*dll_scheme_apply)(Scheme_Object *rator, int num_rands,
+	Scheme_Object **rands);
+static Scheme_Object *(*dll_scheme_builtin_value)(const char *name);
+# if MZSCHEME_VERSION_MAJOR >= 299
+static Scheme_Object *(*dll_scheme_byte_string_to_char_string)(Scheme_Object *s);
+static Scheme_Object *(*dll_scheme_make_path)(const char *chars);
+# endif
+static void (*dll_scheme_close_input_port)(Scheme_Object *port);
+static void (*dll_scheme_count_lines)(Scheme_Object *port);
+#if MZSCHEME_VERSION_MAJOR < 360
+static Scheme_Object *(*dll_scheme_current_continuation_marks)(void);
+#else
+static Scheme_Object *(*dll_scheme_current_continuation_marks)(Scheme_Object *prompt_tag);
+#endif
+static void (*dll_scheme_display)(Scheme_Object *obj, Scheme_Object *port);
+static char *(*dll_scheme_display_to_string)(Scheme_Object *obj, OUTPUT_LEN_TYPE *len);
+static int (*dll_scheme_eq)(Scheme_Object *obj1, Scheme_Object *obj2);
+static Scheme_Object *(*dll_scheme_do_eval)(Scheme_Object *obj,
+	int _num_rands, Scheme_Object **rands, int val);
+static void (*dll_scheme_dont_gc_ptr)(void *p);
+static Scheme_Object *(*dll_scheme_eval)(Scheme_Object *obj, Scheme_Env *env);
+static Scheme_Object *(*dll_scheme_eval_string)(const char *str,
+	Scheme_Env *env);
+static Scheme_Object *(*dll_scheme_eval_string_all)(const char *str,
+	Scheme_Env *env, int all);
+static void (*dll_scheme_finish_primitive_module)(Scheme_Env *env);
+# if MZSCHEME_VERSION_MAJOR < 299
+static char *(*dll_scheme_format)(char *format, int flen, int argc,
+	Scheme_Object **argv, long *rlen);
+# else
+static char *(*dll_scheme_format_utf8)(char *format, int flen, int argc,
+	Scheme_Object **argv, OUTPUT_LEN_TYPE *rlen);
+static Scheme_Object *(*dll_scheme_get_param)(Scheme_Config *c, int pos);
+# endif
+static void (*dll_scheme_gc_ptr_ok)(void *p);
+# if MZSCHEME_VERSION_MAJOR < 299
+static char *(*dll_scheme_get_sized_string_output)(Scheme_Object *,
+	long *len);
+# else
+static char *(*dll_scheme_get_sized_byte_string_output)(Scheme_Object *,
+	OUTPUT_LEN_TYPE *len);
+# endif
+static Scheme_Object *(*dll_scheme_intern_symbol)(const char *name);
+static Scheme_Object *(*dll_scheme_lookup_global)(Scheme_Object *symbol,
+	Scheme_Env *env);
+static Scheme_Object *(*dll_scheme_make_closed_prim_w_arity)
+    (Scheme_Closed_Prim *prim, void *data, const char *name, mzshort mina,
+     mzshort maxa);
+static Scheme_Object *(*dll_scheme_make_integer_value)(long i);
+static Scheme_Object *(*dll_scheme_make_pair)(Scheme_Object *car,
+	Scheme_Object *cdr);
+static Scheme_Object *(*dll_scheme_make_prim_w_arity)(Scheme_Prim *prim,
+	const char *name, mzshort mina, mzshort maxa);
+# if MZSCHEME_VERSION_MAJOR < 299
+static Scheme_Object *(*dll_scheme_make_string)(const char *chars);
+static Scheme_Object *(*dll_scheme_make_string_output_port)();
+# else
+static Scheme_Object *(*dll_scheme_make_byte_string)(const char *chars);
+static Scheme_Object *(*dll_scheme_make_byte_string_output_port)();
+# endif
+static Scheme_Object *(*dll_scheme_make_struct_instance)(Scheme_Object *stype,
+	int argc, Scheme_Object **argv);
+static Scheme_Object **(*dll_scheme_make_struct_names)(Scheme_Object *base,
+	Scheme_Object *field_names, int flags, int *count_out);
+static Scheme_Object *(*dll_scheme_make_struct_type)(Scheme_Object *base,
+	Scheme_Object *parent, Scheme_Object *inspector, int num_fields,
+	int num_uninit_fields, Scheme_Object *uninit_val,
+	Scheme_Object *properties
+# if MZSCHEME_VERSION_MAJOR >= 299
+	, Scheme_Object *guard
+# endif
+	);
+static Scheme_Object **(*dll_scheme_make_struct_values)(
+	Scheme_Object *struct_type, Scheme_Object **names, int count,
+	int flags);
+static Scheme_Type (*dll_scheme_make_type)(const char *name);
+static Scheme_Object *(*dll_scheme_make_vector)(int size,
+	Scheme_Object *fill);
+static void *(*dll_scheme_malloc_fail_ok)(void *(*f)(size_t), size_t);
+static Scheme_Object *(*dll_scheme_open_input_file)(const char *name,
+	const char *who);
+static Scheme_Env *(*dll_scheme_primitive_module)(Scheme_Object *name,
+	Scheme_Env *for_env);
+static int (*dll_scheme_proper_list_length)(Scheme_Object *list);
+static void (*dll_scheme_raise)(Scheme_Object *exn);
+static Scheme_Object *(*dll_scheme_read)(Scheme_Object *port);
+static void (*dll_scheme_signal_error)(const char *msg, ...);
+static void (*dll_scheme_wrong_type)(const char *name, const char *expected,
+	int which, int argc, Scheme_Object **argv);
+# if MZSCHEME_VERSION_MAJOR >= 299
+static void (*dll_scheme_set_param)(Scheme_Config *c, int pos,
+	Scheme_Object *o);
+static Scheme_Config *(*dll_scheme_current_config)(void);
+static Scheme_Object *(*dll_scheme_char_string_to_byte_string)
+    (Scheme_Object *s);
+static Scheme_Object *(*dll_scheme_char_string_to_path)
+    (Scheme_Object *s);
+static void *(*dll_scheme_set_collects_path)(Scheme_Object *p);
+# endif
+static Scheme_Hash_Table *(*dll_scheme_make_hash_table)(int type);
+static void (*dll_scheme_hash_set)(Scheme_Hash_Table *table,
+	Scheme_Object *key, Scheme_Object *value);
+static Scheme_Object *(*dll_scheme_hash_get)(Scheme_Hash_Table *table,
+	Scheme_Object *key);
+static Scheme_Object *(*dll_scheme_make_double)(double d);
+static Scheme_Object *(*dll_scheme_make_sized_byte_string)(char *chars,
+	long len, int copy);
+static Scheme_Object *(*dll_scheme_namespace_require)(Scheme_Object *req);
+static Scheme_Object *(*dll_scheme_dynamic_wind)(void (*pre)(void *), Scheme_Object *(* volatile act)(void *), void (* volatile post)(void *), Scheme_Object *(*jmp_handler)(void *), void * volatile data);
+# ifdef MZ_PRECISE_GC
+static void *(*dll_GC_malloc_one_tagged)(size_t size_in_bytes);
+static void (*dll_GC_register_traversers)(short tag, Size_Proc size, Mark_Proc mark, Fixup_Proc fixup, int is_constant_size, int is_atomic);
+# endif
+# if MZSCHEME_VERSION_MAJOR >= 400
+static void (*dll_scheme_init_collection_paths)(Scheme_Env *global_env, Scheme_Object *extra_dirs);
+static void **(*dll_scheme_malloc_immobile_box)(void *p);
+static void (*dll_scheme_free_immobile_box)(void **b);
+# endif
+# if MZSCHEME_VERSION_MAJOR >= 500
+#  ifdef TRAMPOLINED_MZVIM_STARTUP
+static int (*dll_scheme_main_setup)(int no_auto_statics, Scheme_Env_Main _main, int argc, char **argv);
+#   if defined(IMPLEMENT_THREAD_LOCAL_VIA_WIN_TLS) || MZSCHEME_VERSION_MAJOR >= 603
+static void (*dll_scheme_register_tls_space)(void *tls_space, int _tls_index);
+#   endif
+#  endif
+#  if defined(IMPLEMENT_THREAD_LOCAL_VIA_WIN_TLS) || defined(IMPLEMENT_THREAD_LOCAL_EXTERNALLY_VIA_PROC)
+static Thread_Local_Variables *(*dll_scheme_external_get_thread_local_variables)(void);
+#  endif
+# endif
+# if MZSCHEME_VERSION_MAJOR >= 600
+static void (*dll_scheme_embedded_load)(intptr_t len, const char *s, int predefined);
+static void (*dll_scheme_register_embedded_load)(intptr_t len, const char *s);
+static void (*dll_scheme_set_config_path)(Scheme_Object *p);
+# endif
+
+#if defined(DYNAMIC_MZSCHEME) // not when defined(PROTO)
+
+// arrays are imported directly
+# define scheme_eof dll_scheme_eof
+# define scheme_false dll_scheme_false
+# define scheme_void dll_scheme_void
+# define scheme_null dll_scheme_null
+# define scheme_true dll_scheme_true
+
+// pointers are GetProceAddress'ed as pointers to pointer
+#if !defined(USE_THREAD_LOCAL) && !defined(LINK_EXTENSIONS_BY_TABLE)
+#  define scheme_current_thread (*dll_scheme_current_thread_ptr)
+# endif
+# define scheme_console_printf (*dll_scheme_console_printf_ptr)
+# define scheme_console_output (*dll_scheme_console_output_ptr)
+# define scheme_notify_multithread (*dll_scheme_notify_multithread_ptr)
+
+// and functions in a usual way
+# define GC_malloc dll_GC_malloc
+# define GC_malloc_atomic dll_GC_malloc_atomic
+
+# define scheme_add_global dll_scheme_add_global
+# define scheme_add_global_symbol dll_scheme_add_global_symbol
+# define scheme_apply dll_scheme_apply
+# define scheme_basic_env dll_scheme_basic_env
+# define scheme_builtin_value dll_scheme_builtin_value
+# if MZSCHEME_VERSION_MAJOR >= 299
+#  define scheme_byte_string_to_char_string dll_scheme_byte_string_to_char_string
+#  define scheme_make_path dll_scheme_make_path
+# endif
+# define scheme_check_threads dll_scheme_check_threads
+# define scheme_close_input_port dll_scheme_close_input_port
+# define scheme_count_lines dll_scheme_count_lines
+# define scheme_current_continuation_marks \
+    dll_scheme_current_continuation_marks
+# define scheme_display dll_scheme_display
+# define scheme_display_to_string dll_scheme_display_to_string
+# define scheme_do_eval dll_scheme_do_eval
+# define scheme_dont_gc_ptr dll_scheme_dont_gc_ptr
+# define scheme_eq dll_scheme_eq
+# define scheme_eval dll_scheme_eval
+# define scheme_eval_string dll_scheme_eval_string
+# define scheme_eval_string_all dll_scheme_eval_string_all
+# define scheme_finish_primitive_module dll_scheme_finish_primitive_module
+# if MZSCHEME_VERSION_MAJOR < 299
+#  define scheme_format dll_scheme_format
+# else
+#  define scheme_format_utf8 dll_scheme_format_utf8
+# endif
+# define scheme_gc_ptr_ok dll_scheme_gc_ptr_ok
+# if MZSCHEME_VERSION_MAJOR < 299
+#  define scheme_get_sized_byte_string_output dll_scheme_get_sized_string_output
+# else
+#  define scheme_get_sized_byte_string_output \
+    dll_scheme_get_sized_byte_string_output
+#  define scheme_get_param dll_scheme_get_param
+# endif
+# define scheme_intern_symbol dll_scheme_intern_symbol
+# define scheme_lookup_global dll_scheme_lookup_global
+# define scheme_make_closed_prim_w_arity dll_scheme_make_closed_prim_w_arity
+# define scheme_make_integer_value dll_scheme_make_integer_value
+# define scheme_make_pair dll_scheme_make_pair
+# define scheme_make_prim_w_arity dll_scheme_make_prim_w_arity
+# if MZSCHEME_VERSION_MAJOR < 299
+#  define scheme_make_byte_string dll_scheme_make_string
+#  define scheme_make_byte_string_output_port dll_scheme_make_string_output_port
+# else
+#  define scheme_make_byte_string dll_scheme_make_byte_string
+#  define scheme_make_byte_string_output_port \
+    dll_scheme_make_byte_string_output_port
+# endif
+# define scheme_make_struct_instance dll_scheme_make_struct_instance
+# define scheme_make_struct_names dll_scheme_make_struct_names
+# define scheme_make_struct_type dll_scheme_make_struct_type
+# define scheme_make_struct_values dll_scheme_make_struct_values
+# define scheme_make_type dll_scheme_make_type
+# define scheme_make_vector dll_scheme_make_vector
+# define scheme_malloc_fail_ok dll_scheme_malloc_fail_ok
+# define scheme_open_input_file dll_scheme_open_input_file
+# define scheme_primitive_module dll_scheme_primitive_module
+# define scheme_proper_list_length dll_scheme_proper_list_length
+# define scheme_raise dll_scheme_raise
+# define scheme_read dll_scheme_read
+# define scheme_register_static dll_scheme_register_static
+# define scheme_set_stack_base dll_scheme_set_stack_base
+# define scheme_signal_error dll_scheme_signal_error
+# define scheme_wrong_type dll_scheme_wrong_type
+# if MZSCHEME_VERSION_MAJOR >= 299
+#  define scheme_set_param dll_scheme_set_param
+#  define scheme_current_config dll_scheme_current_config
+#  define scheme_char_string_to_byte_string \
+    dll_scheme_char_string_to_byte_string
+#  define scheme_char_string_to_path \
+    dll_scheme_char_string_to_path
+#  define scheme_set_collects_path dll_scheme_set_collects_path
+# endif
+# define scheme_make_hash_table dll_scheme_make_hash_table
+# define scheme_hash_set dll_scheme_hash_set
+# define scheme_hash_get dll_scheme_hash_get
+# define scheme_make_double dll_scheme_make_double
+# define scheme_make_sized_byte_string dll_scheme_make_sized_byte_string
+# define scheme_namespace_require dll_scheme_namespace_require
+# define scheme_dynamic_wind dll_scheme_dynamic_wind
+# ifdef MZ_PRECISE_GC
+#  define GC_malloc_one_tagged dll_GC_malloc_one_tagged
+#  define GC_register_traversers dll_GC_register_traversers
+# endif
+# if MZSCHEME_VERSION_MAJOR >= 400
+#  ifdef TRAMPOLINED_MZVIM_STARTUP
+#   define scheme_main_setup dll_scheme_main_setup
+#   if defined(IMPLEMENT_THREAD_LOCAL_VIA_WIN_TLS) || MZSCHEME_VERSION_MAJOR >= 603
+#    define scheme_register_tls_space dll_scheme_register_tls_space
+#   endif
+#  endif
+#  define scheme_init_collection_paths dll_scheme_init_collection_paths
+#  define scheme_malloc_immobile_box dll_scheme_malloc_immobile_box
+#  define scheme_free_immobile_box dll_scheme_free_immobile_box
+# endif
+# if MZSCHEME_VERSION_MAJOR >= 600
+#  define scheme_embedded_load dll_scheme_embedded_load
+#  define scheme_register_embedded_load dll_scheme_register_embedded_load
+#  define scheme_set_config_path dll_scheme_set_config_path
+# endif
+
+# if MZSCHEME_VERSION_MAJOR >= 500
+#  if defined(IMPLEMENT_THREAD_LOCAL_VIA_WIN_TLS) || defined(IMPLEMENT_THREAD_LOCAL_EXTERNALLY_VIA_PROC)
+// define as function for macro in schthread.h
+Thread_Local_Variables *
+scheme_external_get_thread_local_variables(void)
+{
+    return dll_scheme_external_get_thread_local_variables();
+}
+#  endif
+# endif
+
+#endif
+
+typedef struct
+{
+    char    *name;
+    void    **ptr;
+} Thunk_Info;
+
+static Thunk_Info mzgc_imports[] = {
+    {"GC_malloc", (void **)&dll_GC_malloc},
+    {"GC_malloc_atomic", (void **)&dll_GC_malloc_atomic},
+    {NULL, NULL}};
+
+static Thunk_Info mzsch_imports[] = {
+    {"scheme_eof", (void **)&dll_scheme_eof},
+    {"scheme_false", (void **)&dll_scheme_false},
+    {"scheme_void", (void **)&dll_scheme_void},
+    {"scheme_null", (void **)&dll_scheme_null},
+    {"scheme_true", (void **)&dll_scheme_true},
+#if !defined(USE_THREAD_LOCAL) && !defined(LINK_EXTENSIONS_BY_TABLE)
+    {"scheme_current_thread", (void **)&dll_scheme_current_thread_ptr},
+#endif
+    {"scheme_console_printf", (void **)&dll_scheme_console_printf_ptr},
+    {"scheme_console_output", (void **)&dll_scheme_console_output_ptr},
+    {"scheme_notify_multithread",
+	(void **)&dll_scheme_notify_multithread_ptr},
+    {"scheme_add_global", (void **)&dll_scheme_add_global},
+    {"scheme_add_global_symbol", (void **)&dll_scheme_add_global_symbol},
+    {"scheme_apply", (void **)&dll_scheme_apply},
+    {"scheme_basic_env", (void **)&dll_scheme_basic_env},
+# if MZSCHEME_VERSION_MAJOR >= 299
+    {"scheme_byte_string_to_char_string", (void **)&dll_scheme_byte_string_to_char_string},
+    {"scheme_make_path", (void **)&dll_scheme_make_path},
+# endif
+    {"scheme_builtin_value", (void **)&dll_scheme_builtin_value},
+    {"scheme_check_threads", (void **)&dll_scheme_check_threads},
+    {"scheme_close_input_port", (void **)&dll_scheme_close_input_port},
+    {"scheme_count_lines", (void **)&dll_scheme_count_lines},
+    {"scheme_current_continuation_marks",
+	(void **)&dll_scheme_current_continuation_marks},
+    {"scheme_display", (void **)&dll_scheme_display},
+    {"scheme_display_to_string", (void **)&dll_scheme_display_to_string},
+    {"scheme_do_eval", (void **)&dll_scheme_do_eval},
+    {"scheme_dont_gc_ptr", (void **)&dll_scheme_dont_gc_ptr},
+    {"scheme_eq", (void **)&dll_scheme_eq},
+    {"scheme_eval", (void **)&dll_scheme_eval},
+    {"scheme_eval_string", (void **)&dll_scheme_eval_string},
+    {"scheme_eval_string_all", (void **)&dll_scheme_eval_string_all},
+    {"scheme_finish_primitive_module",
+	(void **)&dll_scheme_finish_primitive_module},
+# if MZSCHEME_VERSION_MAJOR < 299
+    {"scheme_format", (void **)&dll_scheme_format},
+# else
+    {"scheme_format_utf8", (void **)&dll_scheme_format_utf8},
+    {"scheme_get_param", (void **)&dll_scheme_get_param},
+#endif
+    {"scheme_gc_ptr_ok", (void **)&dll_scheme_gc_ptr_ok},
+# if MZSCHEME_VERSION_MAJOR < 299
+    {"scheme_get_sized_string_output",
+	(void **)&dll_scheme_get_sized_string_output},
+# else
+    {"scheme_get_sized_byte_string_output",
+	(void **)&dll_scheme_get_sized_byte_string_output},
+#endif
+    {"scheme_intern_symbol", (void **)&dll_scheme_intern_symbol},
+    {"scheme_lookup_global", (void **)&dll_scheme_lookup_global},
+    {"scheme_make_closed_prim_w_arity",
+	(void **)&dll_scheme_make_closed_prim_w_arity},
+    {"scheme_make_integer_value", (void **)&dll_scheme_make_integer_value},
+    {"scheme_make_pair", (void **)&dll_scheme_make_pair},
+    {"scheme_make_prim_w_arity", (void **)&dll_scheme_make_prim_w_arity},
+# if MZSCHEME_VERSION_MAJOR < 299
+    {"scheme_make_string", (void **)&dll_scheme_make_string},
+    {"scheme_make_string_output_port",
+	(void **)&dll_scheme_make_string_output_port},
+# else
+    {"scheme_make_byte_string", (void **)&dll_scheme_make_byte_string},
+    {"scheme_make_byte_string_output_port",
+	(void **)&dll_scheme_make_byte_string_output_port},
+# endif
+    {"scheme_make_struct_instance",
+	(void **)&dll_scheme_make_struct_instance},
+    {"scheme_make_struct_names", (void **)&dll_scheme_make_struct_names},
+    {"scheme_make_struct_type", (void **)&dll_scheme_make_struct_type},
+    {"scheme_make_struct_values", (void **)&dll_scheme_make_struct_values},
+    {"scheme_make_type", (void **)&dll_scheme_make_type},
+    {"scheme_make_vector", (void **)&dll_scheme_make_vector},
+    {"scheme_malloc_fail_ok", (void **)&dll_scheme_malloc_fail_ok},
+    {"scheme_open_input_file", (void **)&dll_scheme_open_input_file},
+    {"scheme_primitive_module", (void **)&dll_scheme_primitive_module},
+    {"scheme_proper_list_length", (void **)&dll_scheme_proper_list_length},
+    {"scheme_raise", (void **)&dll_scheme_raise},
+    {"scheme_read", (void **)&dll_scheme_read},
+    {"scheme_register_static", (void **)&dll_scheme_register_static},
+    {"scheme_set_stack_base", (void **)&dll_scheme_set_stack_base},
+    {"scheme_signal_error", (void **)&dll_scheme_signal_error},
+    {"scheme_wrong_type", (void **)&dll_scheme_wrong_type},
+# if MZSCHEME_VERSION_MAJOR >= 299
+    {"scheme_set_param", (void **)&dll_scheme_set_param},
+    {"scheme_current_config", (void **)&dll_scheme_current_config},
+    {"scheme_char_string_to_byte_string",
+	(void **)&dll_scheme_char_string_to_byte_string},
+    {"scheme_char_string_to_path", (void **)&dll_scheme_char_string_to_path},
+    {"scheme_set_collects_path", (void **)&dll_scheme_set_collects_path},
+# endif
+    {"scheme_make_hash_table", (void **)&dll_scheme_make_hash_table},
+    {"scheme_hash_set", (void **)&dll_scheme_hash_set},
+    {"scheme_hash_get", (void **)&dll_scheme_hash_get},
+    {"scheme_make_double", (void **)&dll_scheme_make_double},
+    {"scheme_make_sized_byte_string", (void **)&dll_scheme_make_sized_byte_string},
+    {"scheme_namespace_require", (void **)&dll_scheme_namespace_require},
+    {"scheme_dynamic_wind", (void **)&dll_scheme_dynamic_wind},
+# ifdef MZ_PRECISE_GC
+    {"GC_malloc_one_tagged", (void **)&dll_GC_malloc_one_tagged},
+    {"GC_register_traversers", (void **)&dll_GC_register_traversers},
+# endif
+# if MZSCHEME_VERSION_MAJOR >= 400
+#  ifdef TRAMPOLINED_MZVIM_STARTUP
+    {"scheme_main_setup", (void **)&dll_scheme_main_setup},
+#   if defined(IMPLEMENT_THREAD_LOCAL_VIA_WIN_TLS) || MZSCHEME_VERSION_MAJOR >= 603
+    {"scheme_register_tls_space", (void **)&dll_scheme_register_tls_space},
+#   endif
+#  endif
+    {"scheme_init_collection_paths", (void **)&dll_scheme_init_collection_paths},
+    {"scheme_malloc_immobile_box", (void **)&dll_scheme_malloc_immobile_box},
+    {"scheme_free_immobile_box", (void **)&dll_scheme_free_immobile_box},
+# endif
+# if MZSCHEME_VERSION_MAJOR >= 500
+#  if defined(IMPLEMENT_THREAD_LOCAL_VIA_WIN_TLS) || defined(IMPLEMENT_THREAD_LOCAL_EXTERNALLY_VIA_PROC)
+    {"scheme_external_get_thread_local_variables", (void **)&dll_scheme_external_get_thread_local_variables},
+#  endif
+# endif
+# if MZSCHEME_VERSION_MAJOR >= 600
+    {"scheme_embedded_load", (void **)&dll_scheme_embedded_load},
+    {"scheme_register_embedded_load", (void **)&dll_scheme_register_embedded_load},
+    {"scheme_set_config_path", (void **)&dll_scheme_set_config_path},
+# endif
+    {NULL, NULL}};
+
+static HINSTANCE hMzGC = 0;
+static HINSTANCE hMzSch = 0;
+
+static void dynamic_mzscheme_end(void);
+static int mzscheme_runtime_link_init(char *sch_dll, char *gc_dll,
+	int verbose);
+
+    static int
+mzscheme_runtime_link_init(char *sch_dll, char *gc_dll, int verbose)
+{
+    Thunk_Info *thunk = NULL;
+
+    if (hMzGC && hMzSch)
+	return OK;
+    hMzSch = vimLoadLib(sch_dll);
+    hMzGC = vimLoadLib(gc_dll);
+
+    if (!hMzGC)
+    {
+	if (verbose)
+	    semsg(_(e_could_not_load_library_str_str), gc_dll, GetWin32Error());
+	return FAIL;
+    }
+
+    if (!hMzSch)
+    {
+	if (verbose)
+	    semsg(_(e_could_not_load_library_str_str), sch_dll, GetWin32Error());
+	return FAIL;
+    }
+
+    for (thunk = mzsch_imports; thunk->name; thunk++)
+    {
+	if ((*thunk->ptr =
+		    (void *)GetProcAddress(hMzSch, thunk->name)) == NULL)
+	{
+	    FreeLibrary(hMzSch);
+	    hMzSch = 0;
+	    FreeLibrary(hMzGC);
+	    hMzGC = 0;
+	    if (verbose)
+		semsg(_(e_could_not_load_library_function_str), thunk->name);
+	    return FAIL;
+	}
+    }
+    for (thunk = mzgc_imports; thunk->name; thunk++)
+    {
+	if ((*thunk->ptr =
+		    (void *)GetProcAddress(hMzGC, thunk->name)) == NULL)
+	{
+	    FreeLibrary(hMzSch);
+	    hMzSch = 0;
+	    FreeLibrary(hMzGC);
+	    hMzGC = 0;
+	    if (verbose)
+		semsg(_(e_could_not_load_library_function_str), thunk->name);
+	    return FAIL;
+	}
+    }
+    return OK;
+}
+
+    int
+mzscheme_enabled(int verbose)
+{
+    return mzscheme_runtime_link_init(
+	    (char *)p_mzschemedll, (char *)p_mzschemegcdll, verbose) == OK;
+}
+
+    static void
+dynamic_mzscheme_end(void)
+{
+    if (hMzSch)
+    {
+	FreeLibrary(hMzSch);
+	hMzSch = 0;
+    }
+    if (hMzGC)
+    {
+	FreeLibrary(hMzGC);
+	hMzGC = 0;
+    }
+}
+#endif // DYNAMIC_MZSCHEME
+
+#if MZSCHEME_VERSION_MAJOR < 299
+# define GUARANTEED_STRING_ARG(proc, num) GUARANTEE_STRING(proc, num)
+#else
+    static Scheme_Object *
+guaranteed_byte_string_arg(char *proc, int num, int argc, Scheme_Object **argv)
+{
+    if (SCHEME_BYTE_STRINGP(argv[num]))
+    {
+	return argv[num];
+    }
+    else if (SCHEME_CHAR_STRINGP(argv[num]))
+    {
+	Scheme_Object *tmp = NULL;
+	MZ_GC_DECL_REG(2);
+	MZ_GC_VAR_IN_REG(0, argv[num]);
+	MZ_GC_VAR_IN_REG(1, tmp);
+	MZ_GC_REG();
+	tmp = scheme_char_string_to_byte_string(argv[num]);
+	MZ_GC_UNREG();
+	return tmp;
+    }
+    else
+	scheme_wrong_type(proc, "string", num, argc, argv);
+    // unreachable
+    return scheme_void;
+}
+# define GUARANTEED_STRING_ARG(proc, num) guaranteed_byte_string_arg(proc, num, argc, argv)
+#endif
+
+// need to put it here for dynamic stuff to work
+#if defined(INCLUDE_MZSCHEME_BASE)
+# include "mzscheme_base.c"
+#endif
+
+/*
+ *========================================================================
+ *  1. MzScheme interpreter startup
+ *========================================================================
+ */
+
+static Scheme_Type mz_buffer_type;
+static Scheme_Type mz_window_type;
+
+static int initialized = FALSE;
+#ifdef DYNAMIC_MZSCHEME
+static int disabled = FALSE;
+#endif
+static int load_base_module_failed = FALSE;
+
+// global environment
+static Scheme_Env    *environment = NULL;
+// output/error handlers
+static Scheme_Object *curout = NULL;
+static Scheme_Object *curerr = NULL;
+// exn:vim exception
+static Scheme_Object *exn_catching_apply = NULL;
+static Scheme_Object *exn_p = NULL;
+static Scheme_Object *exn_message = NULL;
+static Scheme_Object *vim_exn = NULL; // Vim Error exception
+
+#if !defined(MZ_PRECISE_GC) || MZSCHEME_VERSION_MAJOR < 400
+static void *stack_base = NULL;
+#endif
+
+static long range_start;
+static long range_end;
+
+// MzScheme threads scheduling stuff
+static int mz_threads_allow = 0;
+
+#if defined(FEAT_GUI_MSWIN)
+static void CALLBACK timer_proc(HWND, UINT, UINT_PTR, DWORD);
+static UINT timer_id = 0;
+#elif defined(FEAT_GUI_GTK)
+static gboolean timer_proc(gpointer);
+static guint timer_id = 0;
+#elif defined(FEAT_GUI_MOTIF)
+static void timer_proc(XtPointer, XtIntervalId *);
+static XtIntervalId timer_id = (XtIntervalId)0;
+#endif
+
+#if !defined(FEAT_GUI_MSWIN) || defined(VIMDLL) // Win32 console and Unix
+    void
+mzvim_check_threads(void)
+{
+    // Last time MzScheme threads were scheduled
+    static time_t mz_last_time = 0;
+
+    if (mz_threads_allow && p_mzq > 0)
+    {
+	time_t now = time(NULL);
+
+	if ((now - mz_last_time) * 1000 > p_mzq)
+	{
+	    mz_last_time = now;
+	    scheme_check_threads();
+	}
+    }
+}
+#endif
+
+#if defined(MZSCHEME_GUI_THREADS) || defined(PROTO)
+static void setup_timer(void);
+static void remove_timer(void);
+
+// timers are presented in GUI only
+# if defined(FEAT_GUI_MSWIN)
+    static void CALLBACK
+timer_proc(HWND hwnd UNUSED, UINT uMsg UNUSED, UINT_PTR idEvent UNUSED, DWORD dwTime UNUSED)
+# elif defined(FEAT_GUI_GTK)
+    static gboolean
+timer_proc(gpointer data UNUSED)
+# elif defined(FEAT_GUI_MOTIF)
+    static void
+timer_proc(XtPointer timed_out UNUSED, XtIntervalId *interval_id UNUSED)
+# endif
+{
+    scheme_check_threads();
+# if defined(FEAT_GUI_GTK)
+    return TRUE; // continue receiving notifications
+# elif defined(FEAT_GUI_MOTIF)
+    // renew timeout
+    if (mz_threads_allow && p_mzq > 0)
+	timer_id = XtAppAddTimeOut(app_context, p_mzq,
+		timer_proc, NULL);
+# endif
+}
+
+    static void
+setup_timer(void)
+{
+# if defined(FEAT_GUI_MSWIN)
+    timer_id = SetTimer(NULL, 0, p_mzq, timer_proc);
+# elif defined(FEAT_GUI_GTK)
+    timer_id = g_timeout_add((guint)p_mzq, (GSourceFunc)timer_proc, NULL);
+# elif defined(FEAT_GUI_MOTIF)
+    timer_id = XtAppAddTimeOut(app_context, p_mzq, timer_proc, NULL);
+# endif
+}
+
+    static void
+remove_timer(void)
+{
+# if defined(FEAT_GUI_MSWIN)
+    KillTimer(NULL, timer_id);
+# elif defined(FEAT_GUI_GTK)
+    g_source_remove(timer_id);
+# elif defined(FEAT_GUI_MOTIF)
+    XtRemoveTimeOut(timer_id);
+# endif
+    timer_id = 0;
+}
+
+#endif // MZSCHEME_GUI_THREADS
+
+    char *
+did_set_mzquantum(optset_T *args UNUSED)
+{
+#if defined(MZSCHEME_GUI_THREADS)
+    // reset timer
+    if (timer_id != 0)
+	remove_timer();
+    if (mz_threads_allow && p_mzq > 0 && gui.in_use)
+	setup_timer();
+#endif
+    return NULL;
+}
+
+    static void
+notify_multithread(int on)
+{
+    mz_threads_allow = on;
+#ifdef MZSCHEME_GUI_THREADS
+    if (on && timer_id == 0 && p_mzq > 0 && gui.in_use)
+	setup_timer();
+    if (!on && timer_id != 0)
+	remove_timer();
+#endif
+}
+
+    void
+mzscheme_end(void)
+{
+    // We can not unload the DLL.  Racket's thread might be still alive.
+#if 0
+#ifdef DYNAMIC_MZSCHEME
+    dynamic_mzscheme_end();
+#endif
+#endif
+}
+
+#if HAVE_TLS_SPACE
+# if defined(_MSC_VER)
+static __declspec(thread) void *tls_space;
+extern intptr_t _tls_index;
+# elif defined(__MINGW32__)
+static __thread void *tls_space;
+extern intptr_t _tls_index;
+# else
+static THREAD_LOCAL void *tls_space;
+static intptr_t _tls_index = 0;
+# endif
+#endif
+
+/*
+ * mzscheme_main() is called early in main().
+ * We may call scheme_main_setup() which calls mzscheme_env_main() which then
+ * trampolines into vim_main2(), which never returns.
+ */
+    int
+mzscheme_main(void)
+{
+    int	    argc = 0;
+    char    *argv = NULL;
+
+#ifdef DYNAMIC_MZSCHEME
+    /*
+     * Racket requires trampolined startup.  We can not load it later.
+     * If dynamic dll loading is failed, disable it.
+     */
+    if (!mzscheme_enabled(FALSE))
+    {
+	disabled = TRUE;
+	return vim_main2();
+    }
+#endif
+#ifdef HAVE_TLS_SPACE
+    scheme_register_tls_space(&tls_space, _tls_index);
+#endif
+#ifdef TRAMPOLINED_MZVIM_STARTUP
+    return scheme_main_setup(TRUE, mzscheme_env_main, argc, &argv);
+#else
+    return mzscheme_env_main(NULL, argc, &argv);
+#endif
+}
+
+    static int
+mzscheme_env_main(Scheme_Env *env, int argc UNUSED, char **argv UNUSED)
+{
+#ifdef TRAMPOLINED_MZVIM_STARTUP
+    // Scheme has created the environment for us
+    environment = env;
+#else
+# ifdef MZ_PRECISE_GC
+    Scheme_Object   *dummy = NULL;
+    MZ_GC_DECL_REG(1);
+    MZ_GC_VAR_IN_REG(0, dummy);
+
+    stack_base = &__gc_var_stack__;
+# else
+    int dummy = 0;
+    stack_base = (void *)&dummy;
+# endif
+#endif
+
+    vim_main2();
+    // not reached, vim_main2() will loop until exit()
+
+    return 0;
+}
+
+    static Scheme_Object*
+load_base_module(void *data)
+{
+    scheme_namespace_require(scheme_intern_symbol((char *)data));
+    return scheme_null;
+}
+
+    static Scheme_Object *
+load_base_module_on_error(void *data UNUSED)
+{
+    load_base_module_failed = TRUE;
+    return scheme_null;
+}
+
+    static int
+startup_mzscheme(void)
+{
+#ifndef TRAMPOLINED_MZVIM_STARTUP
+    scheme_set_stack_base(stack_base, 1);
+#endif
+
+#ifndef TRAMPOLINED_MZVIM_STARTUP
+    // in newer versions of precise GC the initial env has been created
+    environment = scheme_basic_env();
+#endif
+
+    MZ_REGISTER_STATIC(environment);
+    MZ_REGISTER_STATIC(curout);
+    MZ_REGISTER_STATIC(curerr);
+    MZ_REGISTER_STATIC(exn_catching_apply);
+    MZ_REGISTER_STATIC(exn_p);
+    MZ_REGISTER_STATIC(exn_message);
+    MZ_REGISTER_STATIC(vim_exn);
+
+    MZ_GC_CHECK();
+
+#ifdef INCLUDE_MZSCHEME_BASE
+    // invoke function from generated and included mzscheme_base.c
+    declare_modules(environment);
+#endif
+
+    // setup 'current-library-collection-paths' parameter
+# if MZSCHEME_VERSION_MAJOR >= 299
+    {
+	Scheme_Object *coll_path = NULL;
+	int mustfree = FALSE;
+	char_u *s;
+
+	MZ_GC_DECL_REG(1);
+	MZ_GC_VAR_IN_REG(0, coll_path);
+	MZ_GC_REG();
+	// workaround for dynamic loading on windows
+	s = vim_getenv((char_u *)"PLTCOLLECTS", &mustfree);
+	if (s != NULL)
+	{
+	    coll_path = scheme_make_path((char *)s);
+	    MZ_GC_CHECK();
+	    if (mustfree)
+		vim_free(s);
+	}
+#  ifdef MZSCHEME_COLLECTS
+	if (coll_path == NULL)
+	{
+	    coll_path = scheme_make_path(MZSCHEME_COLLECTS);
+	    MZ_GC_CHECK();
+	}
+#  endif
+	if (coll_path != NULL)
+	{
+	    scheme_set_collects_path(coll_path);
+	    MZ_GC_CHECK();
+	}
+	MZ_GC_UNREG();
+    }
+# else
+#  ifdef MZSCHEME_COLLECTS
+    {
+	Scheme_Object	*coll_string = NULL;
+	Scheme_Object	*coll_pair = NULL;
+	Scheme_Config	*config = NULL;
+
+	MZ_GC_DECL_REG(3);
+	MZ_GC_VAR_IN_REG(0, coll_string);
+	MZ_GC_VAR_IN_REG(1, coll_pair);
+	MZ_GC_VAR_IN_REG(2, config);
+	MZ_GC_REG();
+	coll_string = scheme_make_byte_string(MZSCHEME_COLLECTS);
+	MZ_GC_CHECK();
+	coll_pair = scheme_make_pair(coll_string, scheme_null);
+	MZ_GC_CHECK();
+	config = scheme_current_config();
+	MZ_GC_CHECK();
+	scheme_set_param(config, MZCONFIG_COLLECTION_PATHS, coll_pair);
+	MZ_GC_CHECK();
+	MZ_GC_UNREG();
+    }
+# endif
+#endif
+
+# if MZSCHEME_VERSION_MAJOR >= 600
+    {
+	Scheme_Object *config_path = NULL;
+	int mustfree = FALSE;
+	char_u *s;
+
+	MZ_GC_DECL_REG(1);
+	MZ_GC_VAR_IN_REG(0, config_path);
+	MZ_GC_REG();
+	// workaround for dynamic loading on windows
+	s = vim_getenv((char_u *)"PLTCONFIGDIR", &mustfree);
+	if (s != NULL)
+	{
+	    config_path = scheme_make_path((char *)s);
+	    MZ_GC_CHECK();
+	    if (mustfree)
+		vim_free(s);
+	}
+#ifdef MZSCHEME_CONFIGDIR
+	if (config_path == NULL)
+	{
+	    config_path = scheme_make_path(MZSCHEME_CONFIGDIR);
+	    MZ_GC_CHECK();
+	}
+#endif
+	if (config_path != NULL)
+	{
+	    scheme_set_config_path(config_path);
+	    MZ_GC_CHECK();
+	}
+	MZ_GC_UNREG();
+    }
+# endif
+
+#if MZSCHEME_VERSION_MAJOR >= 400
+    scheme_init_collection_paths(environment, scheme_null);
+#endif
+
+    /*
+     * versions 4.x do not provide Scheme bindings by default
+     * we need to add them explicitly
+     */
+    {
+	// use error handler to avoid abort
+	scheme_dynamic_wind(NULL, load_base_module, NULL,
+				    load_base_module_on_error, "racket/base");
+	if (load_base_module_failed)
+	{
+	    load_base_module_failed = FALSE;
+	    scheme_dynamic_wind(NULL, load_base_module, NULL,
+				    load_base_module_on_error, "scheme/base");
+	    if (load_base_module_failed)
+		return -1;
+	}
+    }
+
+    register_vim_exn();
+    // use new environment to initialise exception handling
+    init_exn_catching_apply();
+
+    // redirect output
+    scheme_console_output = do_output;
+    scheme_console_printf = do_printf;
+
+#ifdef HAVE_SANDBOX
+    {
+	Scheme_Object	*make_security_guard = NULL;
+	MZ_GC_DECL_REG(1);
+	MZ_GC_VAR_IN_REG(0, make_security_guard);
+	MZ_GC_REG();
+
+#if MZSCHEME_VERSION_MAJOR < 400
+	{
+	    Scheme_Object	*make_security_guard_symbol = NULL;
+	    MZ_GC_DECL_REG(1);
+	    MZ_GC_VAR_IN_REG(0, make_security_guard_symbol);
+	    MZ_GC_REG();
+	    make_security_guard_symbol = scheme_intern_symbol("make-security-guard");
+	    MZ_GC_CHECK();
+	    make_security_guard = scheme_lookup_global(
+		    make_security_guard_symbol, environment);
+	    MZ_GC_UNREG();
+	}
+#else
+	make_security_guard = scheme_builtin_value("make-security-guard");
+	MZ_GC_CHECK();
+#endif
+
+	// setup sandbox guards
+	if (make_security_guard != NULL)
+	{
+	    Scheme_Object   *args[3] = {NULL, NULL, NULL};
+	    Scheme_Object   *guard = NULL;
+	    Scheme_Config   *config = NULL;
+	    MZ_GC_DECL_REG(5);
+	    MZ_GC_ARRAY_VAR_IN_REG(0, args, 3);
+	    MZ_GC_VAR_IN_REG(3, guard);
+	    MZ_GC_VAR_IN_REG(4, config);
+	    MZ_GC_REG();
+	    config = scheme_current_config();
+	    MZ_GC_CHECK();
+	    args[0] = scheme_get_param(config, MZCONFIG_SECURITY_GUARD);
+	    MZ_GC_CHECK();
+	    args[1] = scheme_make_prim_w_arity(sandbox_file_guard,
+		    "sandbox-file-guard", 3, 3);
+	    args[2] = scheme_make_prim_w_arity(sandbox_network_guard,
+		    "sandbox-network-guard", 4, 4);
+	    guard = scheme_apply(make_security_guard, 3, args);
+	    MZ_GC_CHECK();
+	    scheme_set_param(config, MZCONFIG_SECURITY_GUARD, guard);
+	    MZ_GC_CHECK();
+	    MZ_GC_UNREG();
+	}
+	MZ_GC_UNREG();
+    }
+#endif
+    // Create buffer and window types for use in Scheme code
+    mz_buffer_type = scheme_make_type("<vim-buffer>");
+    MZ_GC_CHECK();
+    mz_window_type = scheme_make_type("<vim-window>");
+    MZ_GC_CHECK();
+#ifdef MZ_PRECISE_GC
+    GC_register_traversers(mz_buffer_type,
+	    buffer_size_proc, buffer_mark_proc, buffer_fixup_proc,
+	    TRUE, TRUE);
+    GC_register_traversers(mz_window_type,
+	    window_size_proc, window_mark_proc, window_fixup_proc,
+	    TRUE, TRUE);
+#endif
+
+    make_modules();
+
+    /*
+     * setup callback to receive notifications
+     * whether thread scheduling is (or not) required
+     */
+    scheme_notify_multithread = notify_multithread;
+
+    return 0;
+}
+
+/*
+ * This routine is called for each new invocation of MzScheme
+ * to make sure things are properly initialized.
+ */
+    static int
+mzscheme_init(void)
+{
+    if (!initialized)
+    {
+#ifdef DYNAMIC_MZSCHEME
+	if (disabled || !mzscheme_enabled(TRUE))
+	{
+	    emsg(_(e_sorry_this_command_is_disabled_the_mzscheme_libraries_could_not_be_loaded));
+	    return -1;
+	}
+#endif
+	if (load_base_module_failed || startup_mzscheme())
+	{
+	    emsg(_(e_sorry_this_command_is_disabled_the_mzscheme_racket_base_module_could_not_be_loaded));
+	    return -1;
+	}
+	initialized = TRUE;
+    }
+    {
+	Scheme_Config	*config = NULL;
+	MZ_GC_DECL_REG(1);
+	MZ_GC_VAR_IN_REG(0, config);
+	MZ_GC_REG();
+	config = scheme_current_config();
+	MZ_GC_CHECK();
+	// recreate ports each call effectively clearing these ones
+	curout = scheme_make_byte_string_output_port();
+	MZ_GC_CHECK();
+	curerr = scheme_make_byte_string_output_port();
+	MZ_GC_CHECK();
+	scheme_set_param(config, MZCONFIG_OUTPUT_PORT, curout);
+	MZ_GC_CHECK();
+	scheme_set_param(config, MZCONFIG_ERROR_PORT, curerr);
+	MZ_GC_CHECK();
+	MZ_GC_UNREG();
+    }
+
+    return 0;
+}
+
+/*
+ *========================================================================
+ *  2.  External Interface
+ *========================================================================
+ */
+
+/*
+ * Evaluate command with exception handling
+ */
+    static int
+eval_with_exn_handling(void *data, Scheme_Closed_Prim *what, Scheme_Object **ret)
+{
+    Scheme_Object   *value = NULL;
+    Scheme_Object   *exn = NULL;
+    Scheme_Object   *prim = NULL;
+
+    MZ_GC_DECL_REG(3);
+    MZ_GC_VAR_IN_REG(0, value);
+    MZ_GC_VAR_IN_REG(1, exn);
+    MZ_GC_VAR_IN_REG(2, prim);
+    MZ_GC_REG();
+
+    prim = scheme_make_closed_prim_w_arity(what, data, "mzvim", 0, 0);
+    MZ_GC_CHECK();
+    value = _apply_thunk_catch_exceptions(prim, &exn);
+    MZ_GC_CHECK();
+
+    if (!value)
+    {
+	value = extract_exn_message(exn);
+	// Got an exn?
+	if (value)
+	{
+	    scheme_display(value, curerr);   //  Send to stderr-vim
+	    MZ_GC_CHECK();
+	    do_flush();
+	}
+	MZ_GC_UNREG();
+	// `raise' was called on some arbitrary value
+	return FAIL;
+    }
+
+    if (ret != NULL)	// if pointer to retval supported give it up
+	*ret = value;
+    // Print any result, as long as it's not a void
+    else if (!SCHEME_VOIDP(value))
+    {
+	scheme_display(value, curout);  // Send to stdout-vim
+	MZ_GC_CHECK();
+    }
+
+    do_flush();
+    MZ_GC_UNREG();
+    return OK;
+}
+
+/*
+ * :mzscheme
+ */
+    static int
+do_mzscheme_command(exarg_T *eap, void *data, Scheme_Closed_Prim *what)
+{
+    if (mzscheme_init())
+	return FAIL;
+
+    range_start = eap->line1;
+    range_end = eap->line2;
+
+    return eval_with_exn_handling(data, what, NULL);
+}
+
+/*
+ * Routine called by VIM when deleting a buffer
+ */
+    void
+mzscheme_buffer_free(buf_T *buf)
+{
+    if (buf->b_mzscheme_ref == NULL)
+	return;
+
+    vim_mz_buffer *bp = NULL;
+    MZ_GC_DECL_REG(1);
+    MZ_GC_VAR_IN_REG(0, bp);
+    MZ_GC_REG();
+
+    bp = BUFFER_REF(buf);
+    bp->buf = INVALID_BUFFER_VALUE;
+#ifndef MZ_PRECISE_GC
+    scheme_gc_ptr_ok(bp);
+#else
+    scheme_free_immobile_box(buf->b_mzscheme_ref);
+#endif
+    buf->b_mzscheme_ref = NULL;
+    MZ_GC_CHECK();
+    MZ_GC_UNREG();
+}
+
+/*
+ * Routine called by VIM when deleting a Window
+ */
+    void
+mzscheme_window_free(win_T *win)
+{
+    if (win->w_mzscheme_ref == NULL)
+	return;
+
+    vim_mz_window *wp = NULL;
+    MZ_GC_DECL_REG(1);
+    MZ_GC_VAR_IN_REG(0, wp);
+    MZ_GC_REG();
+    wp = WINDOW_REF(win);
+    wp->win = INVALID_WINDOW_VALUE;
+#ifndef MZ_PRECISE_GC
+    scheme_gc_ptr_ok(wp);
+#else
+    scheme_free_immobile_box(win->w_mzscheme_ref);
+#endif
+    win->w_mzscheme_ref = NULL;
+    MZ_GC_CHECK();
+    MZ_GC_UNREG();
+}
+
+/*
+ * ":mzscheme" (or ":mz")
+ */
+    void
+ex_mzscheme(exarg_T *eap)
+{
+    char_u	*script;
+
+    script = script_get(eap, eap->arg);
+    if (eap->skip)
+	return;
+
+    if (script == NULL)
+	do_mzscheme_command(eap, eap->arg, do_eval);
+    else
+    {
+	do_mzscheme_command(eap, script, do_eval);
+	vim_free(script);
+    }
+}
+
+    static Scheme_Object *
+do_load(void *data, int noargc UNUSED, Scheme_Object **noargv UNUSED)
+{
+    Scheme_Object   *expr = NULL;
+    Scheme_Object   *result = NULL;
+    char	    *file = NULL;
+    Port_Info	    *pinfo = (Port_Info *)data;
+
+    MZ_GC_DECL_REG(3);
+    MZ_GC_VAR_IN_REG(0, expr);
+    MZ_GC_VAR_IN_REG(1, result);
+    MZ_GC_VAR_IN_REG(2, file);
+    MZ_GC_REG();
+
+    file = (char *)scheme_malloc_fail_ok(scheme_malloc_atomic, MAXPATHL + 1);
+    MZ_GC_CHECK();
+
+    // make Vim expansion
+    expand_env((char_u *)pinfo->name, (char_u *)file, MAXPATHL);
+    pinfo->port = scheme_open_input_file(file, "mzfile");
+    MZ_GC_CHECK();
+    scheme_count_lines(pinfo->port);  // to get accurate read error location
+    MZ_GC_CHECK();
+
+    // Like REPL but print only last result
+    while (!SCHEME_EOFP(expr = scheme_read(pinfo->port)))
+    {
+	result = scheme_eval(expr, environment);
+	MZ_GC_CHECK();
+    }
+
+    // errors will be caught in do_mzscheme_command and ex_mzfile
+    scheme_close_input_port(pinfo->port);
+    MZ_GC_CHECK();
+    pinfo->port = NULL;
+    MZ_GC_UNREG();
+    return result;
+}
+
+/*
+ * :mzfile
+ */
+    void
+ex_mzfile(exarg_T *eap)
+{
+    Port_Info	pinfo = {NULL, NULL};
+
+    MZ_GC_DECL_REG(1);
+    MZ_GC_VAR_IN_REG(0, pinfo.port);
+    MZ_GC_REG();
+
+    pinfo.name = (char *)eap->arg;
+    if (do_mzscheme_command(eap, &pinfo, do_load) != OK
+	    && pinfo.port != NULL)	// looks like port was not closed
+    {
+	scheme_close_input_port(pinfo.port);
+	MZ_GC_CHECK();
+    }
+    MZ_GC_UNREG();
+}
+
+
+/*
+ *========================================================================
+ * Exception handling code -- cribbed form the MzScheme sources and
+ * Matthew Flatt's "Inside PLT MzScheme" document.
+ *========================================================================
+ */
+    static void
+init_exn_catching_apply(void)
+{
+    if (exn_catching_apply)
+	return;
+
+    char *e =
+	"(lambda (thunk) "
+	"(with-handlers ([void (lambda (exn) (cons #f exn))]) "
+	"(cons #t (thunk))))";
+
+    exn_catching_apply = scheme_eval_string(e, environment);
+    MZ_GC_CHECK();
+    exn_p = scheme_builtin_value("exn?");
+    MZ_GC_CHECK();
+    exn_message = scheme_builtin_value("exn-message");
+    MZ_GC_CHECK();
+}
+
+/*
+ * This function applies a thunk, returning the Scheme value if there's
+ * no exception, otherwise returning NULL and setting *exn to the raised
+ * value (usually an exn structure).
+ */
+    static Scheme_Object *
+_apply_thunk_catch_exceptions(Scheme_Object *f, Scheme_Object **exn)
+{
+    Scheme_Object *v;
+
+    v = _scheme_apply(exn_catching_apply, 1, &f);
+    // v is a pair: (cons #t value) or (cons #f exn)
+
+    if (SCHEME_TRUEP(SCHEME_CAR(v)))
+	return SCHEME_CDR(v);
+    else
+    {
+	*exn = SCHEME_CDR(v);
+	return NULL;
+    }
+}
+
+    static Scheme_Object *
+extract_exn_message(Scheme_Object *v)
+{
+    if (SCHEME_TRUEP(_scheme_apply(exn_p, 1, &v)))
+	return _scheme_apply(exn_message, 1, &v);
+    else
+	return NULL; // Not an exn structure
+}
+
+    static Scheme_Object *
+do_eval(void *s, int noargc UNUSED, Scheme_Object **noargv UNUSED)
+{
+    return scheme_eval_string_all((char *)s, environment, TRUE);
+}
+
+/*
+ *========================================================================
+ *  3.  MzScheme I/O Handlers
+ *========================================================================
+ */
+    static void
+do_intrnl_output(char *mesg, int error)
+{
+    char *p, *prev;
+
+    prev = mesg;
+    p = strchr(prev, '\n');
+    while (p)
+    {
+	*p = '\0';
+	if (error)
+	    emsg(prev);
+	else
+	    msg(prev);
+	prev = p + 1;
+	p = strchr(prev, '\n');
+    }
+
+    if (error)
+	emsg(prev);
+    else
+	msg(prev);
+}
+
+    static void
+do_output(char *mesg, OUTPUT_LEN_TYPE len UNUSED)
+{
+    // TODO: use len, the string may not be NUL terminated
+    do_intrnl_output(mesg, 0);
+}
+
+    static void
+do_err_output(char *mesg)
+{
+    do_intrnl_output(mesg, 1);
+}
+
+    static void
+do_printf(char *format, ...)
+{
+    do_intrnl_output(format, 1);
+}
+
+    static void
+do_flush(void)
+{
+    char *buff;
+    OUTPUT_LEN_TYPE length;
+
+    buff = scheme_get_sized_byte_string_output(curerr, &length);
+    MZ_GC_CHECK();
+    if (length)
+    {
+	do_err_output(buff);
+	return;
+    }
+
+    buff = scheme_get_sized_byte_string_output(curout, &length);
+    MZ_GC_CHECK();
+    if (length)
+	do_output(buff, length);
+}
+
+/*
+ *========================================================================
+ *  4. Implementation of the Vim Features for MzScheme
+ *========================================================================
+ */
+
+/*
+ * (command {command-string})
+ */
+    static Scheme_Object *
+vim_command(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	*prim = (Vim_Prim *)data;
+    Scheme_Object *cmd = NULL;
+    MZ_GC_DECL_REG(1);
+    MZ_GC_VAR_IN_REG(0, cmd);
+    MZ_GC_REG();
+    cmd = GUARANTEED_STRING_ARG(prim->name, 0);
+
+    // may be use do_cmdline_cmd?
+    do_cmdline(BYTE_STRING_VALUE(cmd), NULL, NULL, DOCMD_NOWAIT|DOCMD_VERBOSE);
+    update_screen(UPD_VALID);
+
+    MZ_GC_UNREG();
+    raise_if_error();
+    return scheme_void;
+}
+
+/*
+ * (eval {expr-string})
+ */
+    static Scheme_Object *
+vim_eval(void *data UNUSED, int argc UNUSED, Scheme_Object **argv UNUSED)
+{
+#ifdef FEAT_EVAL
+    Vim_Prim		*prim = (Vim_Prim *)data;
+    Scheme_Object	*result = NULL;
+    typval_T		*vim_result;
+    Scheme_Object *expr = NULL;
+    MZ_GC_DECL_REG(2);
+    MZ_GC_VAR_IN_REG(0, result);
+    MZ_GC_VAR_IN_REG(1, expr);
+    MZ_GC_REG();
+    expr = GUARANTEED_STRING_ARG(prim->name, 0);
+
+    vim_result = eval_expr(BYTE_STRING_VALUE(expr), NULL);
+
+    if (vim_result == NULL)
+	raise_vim_exn(_("invalid expression"));
+
+    result = vim_to_mzscheme(vim_result);
+    MZ_GC_CHECK();
+    free_tv(vim_result);
+
+    MZ_GC_UNREG();
+    return result;
+#else
+    raise_vim_exn(_("expressions disabled at compile time"));
+    // unreachable
+    return scheme_false;
+#endif
+}
+
+/*
+ * (range-start)
+ */
+    static Scheme_Object *
+get_range_start(void *data UNUSED, int argc UNUSED, Scheme_Object **argv UNUSED)
+{
+    return scheme_make_integer(range_start);
+}
+
+/*
+ * (range-end)
+ */
+    static Scheme_Object *
+get_range_end(void *data UNUSED, int argc UNUSED, Scheme_Object **argv UNUSED)
+{
+    return scheme_make_integer(range_end);
+}
+
+/*
+ * (beep)
+ */
+    static Scheme_Object *
+mzscheme_beep(void *data UNUSED, int argc UNUSED, Scheme_Object **argv UNUSED)
+{
+    vim_beep(BO_LANG);
+    return scheme_void;
+}
+
+static Scheme_Object *M_global = NULL;
+
+/*
+ * (get-option {option-name}) [buffer/window]
+ */
+    static Scheme_Object *
+get_option(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    long	    value;
+    char	    *strval;
+    getoption_T	    rc;
+    Scheme_Object   *rval = NULL;
+    Scheme_Object   *name = NULL;
+    int		    scope = 0;
+    buf_T	    *save_curb = curbuf;
+    win_T	    *save_curw = curwin;
+
+    MZ_GC_DECL_REG(2);
+    MZ_GC_VAR_IN_REG(0, rval);
+    MZ_GC_VAR_IN_REG(1, name);
+    MZ_GC_REG();
+
+    name = GUARANTEED_STRING_ARG(prim->name, 0);
+
+    if (argc > 1)
+    {
+	if (M_global == NULL)
+	{
+	    MZ_REGISTER_STATIC(M_global);
+	    M_global = scheme_intern_symbol("global");
+	    MZ_GC_CHECK();
+	}
+
+	if (argv[1] == M_global)
+	    scope = OPT_GLOBAL;
+	else if (SCHEME_VIMBUFFERP(argv[1]))
+	{
+	    curbuf = get_valid_buffer(argv[1]);
+	    scope = OPT_LOCAL;
+	}
+	else if (SCHEME_VIMWINDOWP(argv[1]))
+	{
+	    win_T *win = get_valid_window(argv[1]);
+
+	    curwin = win;
+	    curbuf = win->w_buffer;
+	    scope = OPT_LOCAL;
+	}
+	else
+	    scheme_wrong_type(prim->name, "vim-buffer/window", 1, argc, argv);
+    }
+
+    rc = get_option_value(BYTE_STRING_VALUE(name), &value, (char_u **)&strval,
+								  NULL, scope);
+    curbuf = save_curb;
+    curwin = save_curw;
+
+    switch (rc)
+    {
+    case gov_bool:
+    case gov_number:
+	MZ_GC_UNREG();
+	return scheme_make_integer_value(value);
+    case gov_string:
+	rval = scheme_make_byte_string(strval);
+	MZ_GC_CHECK();
+	vim_free(strval);
+	MZ_GC_UNREG();
+	return rval;
+    case gov_hidden_bool:
+    case gov_hidden_number:
+    case gov_hidden_string:
+	MZ_GC_UNREG();
+	raise_vim_exn(_("hidden option"));
+	//NOTREACHED
+    case gov_unknown:
+	MZ_GC_UNREG();
+	raise_vim_exn(_("unknown option"));
+	//NOTREACHED
+    }
+    // unreachable
+    return scheme_void;
+}
+
+/*
+ * (set-option {option-changing-string} [buffer/window])
+ */
+    static Scheme_Object *
+set_option(void *data, int argc, Scheme_Object **argv)
+{
+    char_u	*command = NULL;
+    int		scope = 0;
+    buf_T	*save_curb = curbuf;
+    win_T	*save_curw = curwin;
+    Vim_Prim	*prim = (Vim_Prim *)data;
+    Scheme_Object *cmd = NULL;
+
+    MZ_GC_DECL_REG(1);
+    MZ_GC_VAR_IN_REG(0, cmd);
+    MZ_GC_REG();
+    cmd = GUARANTEED_STRING_ARG(prim->name, 0);
+
+    if (argc > 1)
+    {
+	if (M_global == NULL)
+	{
+	    MZ_REGISTER_STATIC(M_global);
+	    M_global = scheme_intern_symbol("global");
+	    MZ_GC_CHECK();
+	}
+
+	if (argv[1] == M_global)
+	    scope = OPT_GLOBAL;
+	else if (SCHEME_VIMBUFFERP(argv[1]))
+	{
+	    curbuf = get_valid_buffer(argv[1]);
+	    scope = OPT_LOCAL;
+	}
+	else if (SCHEME_VIMWINDOWP(argv[1]))
+	{
+	    win_T *win = get_valid_window(argv[1]);
+	    curwin = win;
+	    curbuf = win->w_buffer;
+	    scope = OPT_LOCAL;
+	}
+	else
+	    scheme_wrong_type(prim->name, "vim-buffer/window", 1, argc, argv);
+    }
+
+    // do_set can modify cmd, make copy
+    command = vim_strsave(BYTE_STRING_VALUE(cmd));
+    MZ_GC_UNREG();
+    do_set(command, scope);
+    vim_free(command);
+    update_screen(UPD_NOT_VALID);
+    curbuf = save_curb;
+    curwin = save_curw;
+    raise_if_error();
+    return scheme_void;
+}
+
+/*
+ *===========================================================================
+ *  5. Vim Window-related Manipulation Functions
+ *===========================================================================
+ */
+
+/*
+ * (curr-win)
+ */
+    static Scheme_Object *
+get_curr_win(void *data UNUSED, int argc UNUSED, Scheme_Object **argv UNUSED)
+{
+    return (Scheme_Object *)get_vim_curr_window();
+}
+
+/*
+ * (win-count)
+ */
+    static Scheme_Object *
+get_window_count(void *data UNUSED, int argc UNUSED, Scheme_Object **argv UNUSED)
+{
+    int	    n = 0;
+    win_T   *w;
+
+    FOR_ALL_WINDOWS(w)
+	++n;
+    return scheme_make_integer(n);
+}
+
+/*
+ * (get-win-list [buffer])
+ */
+    static Scheme_Object *
+get_window_list(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_buffer   *buf;
+    Scheme_Object   *list;
+    win_T	    *w = firstwin;
+
+    buf = get_buffer_arg(prim->name, 0, argc, argv);
+    list = scheme_null;
+
+    for ( ; w != NULL; w = w->w_next)
+	if (w->w_buffer == buf->buf)
+	{
+	    list = scheme_make_pair(window_new(w), list);
+	    MZ_GC_CHECK();
+	}
+
+    return list;
+}
+
+    static Scheme_Object *
+window_new(win_T *win)
+{
+    vim_mz_window *self = NULL;
+
+    MZ_GC_DECL_REG(1);
+    MZ_GC_VAR_IN_REG(0, self);
+
+    // We need to handle deletion of windows underneath us.
+    // If we add a "w_mzscheme_ref" field to the win_T structure,
+    // then we can get at it in win_free() in vim.
+    //
+    // On a win_free() we set the Scheme object's win_T *field
+    // to an invalid value. We trap all uses of a window
+    // object, and reject them if the win_T *field is invalid.
+    if (win->w_mzscheme_ref != NULL)
+	return (Scheme_Object *)WINDOW_REF(win);
+
+    MZ_GC_REG();
+    self = scheme_malloc_fail_ok(scheme_malloc_tagged, sizeof(vim_mz_window));
+    CLEAR_POINTER(self);
+#ifndef MZ_PRECISE_GC
+    scheme_dont_gc_ptr(self);	// because win isn't visible to GC
+#else
+    win->w_mzscheme_ref = scheme_malloc_immobile_box(NULL);
+#endif
+    MZ_GC_CHECK();
+    WINDOW_REF(win) = self;
+    MZ_GC_CHECK();
+    self->win = win;
+    self->so.type = mz_window_type;
+
+    MZ_GC_UNREG();
+    return (Scheme_Object *)self;
+}
+
+/*
+ * (get-win-num [window])
+ */
+    static Scheme_Object *
+get_window_num(void *data UNUSED, int argc UNUSED, Scheme_Object **argv UNUSED)
+{
+    int		nr = 1;
+    Vim_Prim	*prim = (Vim_Prim *)data;
+    win_T	*win = get_window_arg(prim->name, 0, argc, argv)->win;
+    win_T	*wp;
+
+    for (wp = firstwin; wp != win; wp = wp->w_next)
+	++nr;
+
+    return scheme_make_integer(nr);
+}
+
+/*
+ * (get-win-by-num {windownum})
+ */
+    static Scheme_Object *
+get_window_by_num(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	*prim = (Vim_Prim *)data;
+    win_T	*win = firstwin;
+    int		fnum;
+
+    fnum = SCHEME_INT_VAL(GUARANTEE_INTEGER(prim->name, 0));
+    if (fnum < 1)
+	scheme_signal_error(_("window index is out of range"));
+
+    for ( ; win != NULL; win = win->w_next, --fnum)
+	if (fnum == 1)	    // to be 1-based
+	    return window_new(win);
+
+    return scheme_false;
+}
+
+/*
+ * (get-win-buffer [window])
+ */
+    static Scheme_Object *
+get_window_buffer(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_window   *win = get_window_arg(prim->name, 0, argc, argv);
+
+    return buffer_new(win->win->w_buffer);
+}
+
+/*
+ * (get-win-height [window])
+ */
+    static Scheme_Object *
+get_window_height(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_window   *win = get_window_arg(prim->name, 0, argc, argv);
+
+    return scheme_make_integer(win->win->w_height);
+}
+
+/*
+ * (set-win-height {height} [window])
+ */
+    static Scheme_Object *
+set_window_height(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_window   *win;
+    win_T	    *savewin;
+    int		    height;
+
+    win = get_window_arg(prim->name, 1, argc, argv);
+    height = SCHEME_INT_VAL(GUARANTEE_INTEGER(prim->name, 0));
+
+#ifdef FEAT_GUI
+    need_mouse_correct = TRUE;
+#endif
+
+    savewin = curwin;
+    curwin = win->win;
+    win_setheight(height);
+    curwin = savewin;
+
+    raise_if_error();
+    return scheme_void;
+}
+
+/*
+ * (get-win-width [window])
+ */
+    static Scheme_Object *
+get_window_width(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_window   *win = get_window_arg(prim->name, 0, argc, argv);
+
+    return scheme_make_integer(win->win->w_width);
+}
+
+/*
+ * (set-win-width {width} [window])
+ */
+    static Scheme_Object *
+set_window_width(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_window   *win;
+    win_T	    *savewin;
+    int		    width = 0;
+
+    win = get_window_arg(prim->name, 1, argc, argv);
+    width = SCHEME_INT_VAL(GUARANTEE_INTEGER(prim->name, 0));
+
+# ifdef FEAT_GUI
+    need_mouse_correct = TRUE;
+# endif
+
+    savewin = curwin;
+    curwin = win->win;
+    win_setwidth(width);
+    curwin = savewin;
+
+    raise_if_error();
+    return scheme_void;
+}
+
+/*
+ * (get-cursor [window]) -> (line . col)
+ */
+    static Scheme_Object *
+get_cursor(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_window   *win;
+    pos_T	    pos;
+
+    win = get_window_arg(prim->name, 0, argc, argv);
+    pos = win->win->w_cursor;
+    return scheme_make_pair(scheme_make_integer_value((long)pos.lnum),
+		    scheme_make_integer_value((long)pos.col + 1));
+}
+
+/*
+ * (set-cursor (line . col) [window])
+ */
+    static Scheme_Object *
+set_cursor(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_window   *win;
+    long	    lnum = 0;
+    long	    col = 0;
+
+#ifdef HAVE_SANDBOX
+    sandbox_check();
+#endif
+    win = get_window_arg(prim->name, 1, argc, argv);
+    GUARANTEE_PAIR(prim->name, 0);
+
+    if (!SCHEME_INTP(SCHEME_CAR(argv[0]))
+	    || !SCHEME_INTP(SCHEME_CDR(argv[0])))
+	scheme_wrong_type(prim->name, "integer pair", 0, argc, argv);
+
+    lnum = SCHEME_INT_VAL(SCHEME_CAR(argv[0]));
+    col = SCHEME_INT_VAL(SCHEME_CDR(argv[0])) - 1;
+
+    check_line_range(lnum, win->win->w_buffer);
+    // don't know how to catch invalid column value
+
+    win->win->w_cursor.lnum = lnum;
+    win->win->w_cursor.col = col;
+    win->win->w_set_curswant = TRUE;
+    update_screen(UPD_VALID);
+
+    raise_if_error();
+    return scheme_void;
+}
+/*
+ *===========================================================================
+ *  6. Vim Buffer-related Manipulation Functions
+ *===========================================================================
+ */
+
+/*
+ * (open-buff {filename})
+ */
+    static Scheme_Object *
+mzscheme_open_buffer(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    int		    num = 0;
+    Scheme_Object   *onum = NULL;
+    Scheme_Object   *buf = NULL;
+    Scheme_Object   *fname;
+
+    MZ_GC_DECL_REG(3);
+    MZ_GC_VAR_IN_REG(0, onum);
+    MZ_GC_VAR_IN_REG(1, buf);
+    MZ_GC_VAR_IN_REG(2, fname);
+    MZ_GC_REG();
+    fname = GUARANTEED_STRING_ARG(prim->name, 0);
+
+#ifdef HAVE_SANDBOX
+    sandbox_check();
+#endif
+    // TODO make open existing file
+    num = buflist_add(BYTE_STRING_VALUE(fname), BLN_LISTED | BLN_CURBUF);
+
+    if (num == 0)
+	raise_vim_exn(_("couldn't open buffer"));
+
+    onum = scheme_make_integer(num);
+    buf = get_buffer_by_num(data, 1, &onum);
+    MZ_GC_UNREG();
+    return buf;
+}
+
+/*
+ * (get-buff-by-num {buffernum})
+ */
+    static Scheme_Object *
+get_buffer_by_num(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	*prim = (Vim_Prim *)data;
+    buf_T	*buf;
+    int		fnum;
+
+    fnum = SCHEME_INT_VAL(GUARANTEE_INTEGER(prim->name, 0));
+
+    FOR_ALL_BUFFERS(buf)
+	if (buf->b_fnum == fnum)
+	    return buffer_new(buf);
+
+    return scheme_false;
+}
+
+/*
+ * (get-buff-by-name {buffername})
+ */
+    static Scheme_Object *
+get_buffer_by_name(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	*prim = (Vim_Prim *)data;
+    buf_T	*buf;
+    Scheme_Object *buffer = NULL;
+    Scheme_Object *fname = NULL;
+
+    MZ_GC_DECL_REG(2);
+    MZ_GC_VAR_IN_REG(0, buffer);
+    MZ_GC_VAR_IN_REG(1, fname);
+    MZ_GC_REG();
+    fname = GUARANTEED_STRING_ARG(prim->name, 0);
+    buffer = scheme_false;
+
+    FOR_ALL_BUFFERS(buf)
+    {
+	if (buf->b_ffname == NULL || buf->b_sfname == NULL)
+	    // empty string
+	{
+	    if (BYTE_STRING_VALUE(fname)[0] == NUL)
+		buffer = buffer_new(buf);
+	}
+	else if (!fnamecmp(buf->b_ffname, BYTE_STRING_VALUE(fname))
+		|| !fnamecmp(buf->b_sfname, BYTE_STRING_VALUE(fname)))
+	{
+	    // either short or long filename matches
+	    buffer = buffer_new(buf);
+	}
+    }
+
+    MZ_GC_UNREG();
+    return buffer;
+}
+
+/*
+ * (get-next-buff [buffer])
+ */
+    static Scheme_Object *
+get_next_buffer(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	*prim = (Vim_Prim *)data;
+    buf_T	*buf = get_buffer_arg(prim->name, 0, argc, argv)->buf;
+
+    if (buf->b_next == NULL)
+	return scheme_false;
+    else
+	return buffer_new(buf->b_next);
+}
+
+/*
+ * (get-prev-buff [buffer])
+ */
+    static Scheme_Object *
+get_prev_buffer(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	*prim = (Vim_Prim *)data;
+    buf_T	*buf = get_buffer_arg(prim->name, 0, argc, argv)->buf;
+
+    if (buf->b_prev == NULL)
+	return scheme_false;
+    else
+	return buffer_new(buf->b_prev);
+}
+
+/*
+ * (get-buff-num [buffer])
+ */
+    static Scheme_Object *
+get_buffer_num(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_buffer   *buf = get_buffer_arg(prim->name, 0, argc, argv);
+
+    return scheme_make_integer(buf->buf->b_fnum);
+}
+
+/*
+ * (buff-count)
+ */
+    static Scheme_Object *
+get_buffer_count(void *data UNUSED, int argc UNUSED, Scheme_Object **argv UNUSED)
+{
+    buf_T   *b;
+    int	    n = 0;
+
+    FOR_ALL_BUFFERS(b) ++n;
+    return scheme_make_integer(n);
+}
+
+/*
+ * (get-buff-name [buffer])
+ */
+    static Scheme_Object *
+get_buffer_name(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_buffer   *buf = get_buffer_arg(prim->name, 0, argc, argv);
+
+    return scheme_make_byte_string((char *)buf->buf->b_ffname);
+}
+
+/*
+ * (curr-buff)
+ */
+    static Scheme_Object *
+get_curr_buffer(void *data UNUSED, int argc UNUSED, Scheme_Object **argv UNUSED)
+{
+    return (Scheme_Object *)get_vim_curr_buffer();
+}
+
+    static Scheme_Object *
+buffer_new(buf_T *buf)
+{
+    vim_mz_buffer *self = NULL;
+
+    MZ_GC_DECL_REG(1);
+    MZ_GC_VAR_IN_REG(0, self);
+
+    // We need to handle deletion of buffers underneath us.
+    // If we add a "b_mzscheme_ref" field to the buf_T structure,
+    // then we can get at it in buf_freeall() in vim.
+    if (buf->b_mzscheme_ref)
+	return (Scheme_Object *)BUFFER_REF(buf);
+
+    MZ_GC_REG();
+    self = scheme_malloc_fail_ok(scheme_malloc_tagged, sizeof(vim_mz_buffer));
+    CLEAR_POINTER(self);
+#ifndef MZ_PRECISE_GC
+    scheme_dont_gc_ptr(self);	// because buf isn't visible to GC
+#else
+    buf->b_mzscheme_ref = scheme_malloc_immobile_box(NULL);
+#endif
+    MZ_GC_CHECK();
+    BUFFER_REF(buf) = self;
+    MZ_GC_CHECK();
+    self->buf = buf;
+    self->so.type = mz_buffer_type;
+
+    MZ_GC_UNREG();
+    return (Scheme_Object *)self;
+}
+
+/*
+ * (get-buff-size [buffer])
+ *
+ * Get the size (number of lines) in the current buffer.
+ */
+    static Scheme_Object *
+get_buffer_size(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_buffer   *buf = get_buffer_arg(prim->name, 0, argc, argv);
+
+    return scheme_make_integer(buf->buf->b_ml.ml_line_count);
+}
+
+/*
+ * (get-buff-line {linenr} [buffer])
+ *
+ * Get a line from the specified buffer. The line number is
+ * in Vim format (1-based). The line is returned as a MzScheme
+ * string object.
+ */
+    static Scheme_Object *
+get_buffer_line(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_buffer   *buf;
+    int		    linenr;
+    char_u	    *line;
+
+    buf = get_buffer_arg(prim->name, 1, argc, argv);
+    linenr = SCHEME_INT_VAL(GUARANTEE_INTEGER(prim->name, 0));
+    line = ml_get_buf(buf->buf, (linenr_T)linenr, FALSE);
+
+    raise_if_error();
+    return scheme_make_byte_string((char *)line);
+}
+
+
+/*
+ * (get-buff-line-list {start} {end} [buffer])
+ *
+ * Get a list of lines from the specified buffer. The line numbers
+ * are in Vim format (1-based). The range is from lo up to, but not
+ * including, hi. The list is returned as a list of string objects.
+ */
+    static Scheme_Object *
+get_buffer_line_list(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_buffer   *buf;
+    int		    i, hi, lo, n;
+    Scheme_Object   *list = NULL;
+
+    MZ_GC_DECL_REG(1);
+    MZ_GC_VAR_IN_REG(0, list);
+    MZ_GC_REG();
+
+    buf = get_buffer_arg(prim->name, 2, argc, argv);
+    list = scheme_null;
+    hi = SCHEME_INT_VAL(GUARANTEE_INTEGER(prim->name, 1));
+    lo = SCHEME_INT_VAL(GUARANTEE_INTEGER(prim->name, 0));
+
+    /*
+     * Handle some error conditions
+     */
+    if (lo < 0)
+	lo = 0;
+
+    if (hi < 0)
+	hi = 0;
+    if (hi < lo)
+	hi = lo;
+
+    n = hi - lo;
+
+    for (i = n; i >= 0; --i)
+    {
+	Scheme_Object *str = scheme_make_byte_string(
+		       (char *)ml_get_buf(buf->buf, (linenr_T)(lo+i), FALSE));
+	raise_if_error();
+
+	// Set the list item
+	list = scheme_make_pair(str, list);
+	MZ_GC_CHECK();
+    }
+    MZ_GC_UNREG();
+    return list;
+}
+
+/*
+ * (set-buff-line {linenr} {string/#f} [buffer])
+ *
+ * Replace a line in the specified buffer. The line number is
+ * in Vim format (1-based). The replacement line is given as
+ * an MzScheme string object. The object is checked for validity
+ * and correct format. An exception is thrown if the values are not
+ * the correct format.
+ *
+ * It returns a Scheme Object that indicates the length of the
+ * string changed.
+ */
+    static Scheme_Object *
+set_buffer_line(void *data, int argc, Scheme_Object **argv)
+{
+    // First of all, we check the value of the supplied MzScheme object.
+    // There are three cases:
+    //	  1. #f - this is a deletion.
+    //	  2. A string	   - this is a replacement.
+    //	  3. Anything else - this is an error.
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_buffer   *buf;
+    Scheme_Object   *line = NULL;
+    char	    *save;
+    int		    n;
+
+    MZ_GC_DECL_REG(1);
+    MZ_GC_VAR_IN_REG(0, line);
+    MZ_GC_REG();
+
+#ifdef HAVE_SANDBOX
+    sandbox_check();
+#endif
+    n = SCHEME_INT_VAL(GUARANTEE_INTEGER(prim->name, 0));
+    if (!SCHEME_STRINGP(argv[1]) && !SCHEME_FALSEP(argv[1]))
+	scheme_wrong_type(prim->name, "string or #f", 1, argc, argv);
+    line = argv[1];
+    buf = get_buffer_arg(prim->name, 2, argc, argv);
+
+    check_line_range(n, buf->buf);
+
+    if (SCHEME_FALSEP(line))
+    {
+	buf_T	    *savebuf = curbuf;
+
+	curbuf = buf->buf;
+
+	if (u_savedel((linenr_T)n, 1L) == FAIL)
+	{
+	    curbuf = savebuf;
+	    raise_vim_exn(_("cannot save undo information"));
+	}
+	else if (ml_delete((linenr_T)n) == FAIL)
+	{
+	    curbuf = savebuf;
+	    raise_vim_exn(_("cannot delete line"));
+	}
+	if (buf->buf == curwin->w_buffer)
+	    mz_fix_cursor(n, n + 1, -1);
+	deleted_lines_mark((linenr_T)n, 1L);
+
+	curbuf = savebuf;
+
+	MZ_GC_UNREG();
+	raise_if_error();
+	return scheme_void;
+    }
+    else
+    {
+	// Otherwise it's a line
+	buf_T	    *savebuf = curbuf;
+
+	save = string_to_line(line);
+
+	curbuf = buf->buf;
+
+	if (u_savesub((linenr_T)n) == FAIL)
+	{
+	    curbuf = savebuf;
+	    vim_free(save);
+	    raise_vim_exn(_("cannot save undo information"));
+	}
+	else if (ml_replace((linenr_T)n, (char_u *)save, TRUE) == FAIL)
+	{
+	    curbuf = savebuf;
+	    vim_free(save);
+	    raise_vim_exn(_("cannot replace line"));
+	}
+	else
+	{
+	    vim_free(save);
+	    changed_bytes((linenr_T)n, 0);
+	}
+
+	curbuf = savebuf;
+
+	// Check that the cursor is not beyond the end of the line now.
+	if (buf->buf == curwin->w_buffer)
+	    check_cursor_col();
+
+	MZ_GC_UNREG();
+	raise_if_error();
+	return scheme_void;
+    }
+}
+
+    static void
+free_array(char **array)
+{
+    char **curr = array;
+    while (*curr != NULL)
+	vim_free(*curr++);
+    vim_free(array);
+}
+
+/*
+ * (set-buff-line-list {start} {end} {string-list/#f/null} [buffer])
+ *
+ * Replace a range of lines in the specified buffer. The line numbers are in
+ * Vim format (1-based). The range is from lo up to, but not including, hi.
+ * The replacement lines are given as a Scheme list of string objects. The
+ * list is checked for validity and correct format.
+ *
+ * Errors are returned as a value of FAIL. The return value is OK on success.
+ * If OK is returned and len_change is not NULL, *len_change is set to the
+ * change in the buffer length.
+ */
+    static Scheme_Object *
+set_buffer_line_list(void *data, int argc, Scheme_Object **argv)
+{
+    // First of all, we check the type of the supplied MzScheme object.
+    // There are three cases:
+    //	  1. #f - this is a deletion.
+    //	  2. A list	   - this is a replacement.
+    //	  3. Anything else - this is an error.
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_buffer   *buf = NULL;
+    Scheme_Object   *line_list = NULL;
+    int		    i, old_len, new_len, hi, lo;
+    long	    extra;
+
+    MZ_GC_DECL_REG(1);
+    MZ_GC_VAR_IN_REG(0, line_list);
+    MZ_GC_REG();
+
+#ifdef HAVE_SANDBOX
+    sandbox_check();
+#endif
+    lo = SCHEME_INT_VAL(GUARANTEE_INTEGER(prim->name, 0));
+    hi = SCHEME_INT_VAL(GUARANTEE_INTEGER(prim->name, 1));
+    if (!SCHEME_PAIRP(argv[2])
+	    && !SCHEME_FALSEP(argv[2]) && !SCHEME_NULLP(argv[2]))
+	scheme_wrong_type(prim->name, "list or #f", 2, argc, argv);
+    line_list = argv[2];
+    buf = get_buffer_arg(prim->name, 3, argc, argv);
+    old_len = hi - lo;
+    if (old_len < 0) // process inverse values wisely
+    {
+	i = lo;
+	lo = hi;
+	hi = i;
+	old_len = -old_len;
+    }
+    extra = 0;
+
+    check_line_range(lo, buf->buf);	    // inclusive
+    check_line_range(hi - 1, buf->buf);	    // exclusive
+
+    if (SCHEME_FALSEP(line_list) || SCHEME_NULLP(line_list))
+    {
+	buf_T	*savebuf = curbuf;
+	curbuf = buf->buf;
+
+	if (u_savedel((linenr_T)lo, (long)old_len) == FAIL)
+	{
+	    curbuf = savebuf;
+	    raise_vim_exn(_("cannot save undo information"));
+	}
+	else
+	{
+	    for (i = 0; i < old_len; i++)
+		if (ml_delete((linenr_T)lo) == FAIL)
+		{
+		    curbuf = savebuf;
+		    raise_vim_exn(_("cannot delete line"));
+		}
+	    if (buf->buf == curwin->w_buffer)
+		mz_fix_cursor(lo, hi, -old_len);
+	    deleted_lines_mark((linenr_T)lo, (long)old_len);
+	}
+
+	curbuf = savebuf;
+
+	MZ_GC_UNREG();
+	raise_if_error();
+	return scheme_void;
+    }
+    else
+    {
+	buf_T	*savebuf = curbuf;
+
+	// List
+	new_len = scheme_proper_list_length(line_list);
+	MZ_GC_CHECK();
+	if (new_len < 0)	// improper or cyclic list
+	    scheme_wrong_type(prim->name, "proper list",
+		    2, argc, argv);
+	else
+	{
+	    char		**array = NULL;
+	    Scheme_Object   *line = NULL;
+	    Scheme_Object   *rest = NULL;
+
+	    MZ_GC_DECL_REG(2);
+	    MZ_GC_VAR_IN_REG(0, line);
+	    MZ_GC_VAR_IN_REG(1, rest);
+	    MZ_GC_REG();
+
+	    array = ALLOC_CLEAR_MULT(char *, new_len + 1);
+
+	    rest = line_list;
+	    for (i = 0; i < new_len; ++i)
+	    {
+		line = SCHEME_CAR(rest);
+		rest = SCHEME_CDR(rest);
+		if (!SCHEME_STRINGP(line))
+		{
+		    free_array(array);
+		    scheme_wrong_type(prim->name, "string-list", 2, argc, argv);
+		}
+		array[i] = string_to_line(line);
+	    }
+
+	    curbuf = buf->buf;
+
+	    if (u_save((linenr_T)(lo-1), (linenr_T)hi) == FAIL)
+	    {
+		curbuf = savebuf;
+		free_array(array);
+		raise_vim_exn(_("cannot save undo information"));
+	    }
+
+	    /*
+	     * If the size of the range is reducing (ie, new_len < old_len) we
+	     * need to delete some old_len. We do this at the start, by
+	     * repeatedly deleting line "lo".
+	     */
+	    for (i = 0; i < old_len - new_len; ++i)
+	    {
+		if (ml_delete((linenr_T)lo) == FAIL)
+		{
+		    curbuf = savebuf;
+		    free_array(array);
+		    raise_vim_exn(_("cannot delete line"));
+		}
+		extra--;
+	    }
+
+	    /*
+	     * For as long as possible, replace the existing old_len with the
+	     * new old_len. This is a more efficient operation, as it requires
+	     * less memory allocation and freeing.
+	     */
+	    for (i = 0; i < old_len && i < new_len; i++)
+		if (ml_replace((linenr_T)(lo+i), (char_u *)array[i], TRUE) == FAIL)
+		{
+		    curbuf = savebuf;
+		    free_array(array);
+		    raise_vim_exn(_("cannot replace line"));
+		}
+
+	    /*
+	     * Now we may need to insert the remaining new_len.  We don't need to
+	     * free the string passed back because MzScheme has control of that
+	     * memory.
+	     */
+	    while (i < new_len)
+	    {
+		if (ml_append((linenr_T)(lo + i - 1),
+			    (char_u *)array[i], 0, FALSE) == FAIL)
+		{
+		    curbuf = savebuf;
+		    free_array(array);
+		    raise_vim_exn(_("cannot insert line"));
+		}
+		++i;
+		++extra;
+	    }
+	    MZ_GC_UNREG();
+	    free_array(array);
+	}
+
+	/*
+	 * Adjust marks. Invalidate any which lie in the
+	 * changed range, and move any in the remainder of the buffer.
+	 */
+	mark_adjust((linenr_T)lo, (linenr_T)(hi - 1),
+						  (long)MAXLNUM, (long)extra);
+	changed_lines((linenr_T)lo, 0, (linenr_T)hi, (long)extra);
+
+	if (buf->buf == curwin->w_buffer)
+	    mz_fix_cursor(lo, hi, extra);
+	curbuf = savebuf;
+
+	MZ_GC_UNREG();
+	raise_if_error();
+	return scheme_void;
+    }
+}
+
+/*
+ * (insert-buff-line-list {linenr} {string/string-list} [buffer])
+ *
+ * Insert a number of lines into the specified buffer after the specified line.
+ * The line number is in Vim format (1-based). The lines to be inserted are
+ * given as an MzScheme list of string objects or as a single string. The lines
+ * to be added are checked for validity and correct format. Errors are
+ * returned as a value of FAIL.  The return value is OK on success.
+ * If OK is returned and len_change is not NULL, *len_change
+ * is set to the change in the buffer length.
+ */
+    static Scheme_Object *
+insert_buffer_line_list(void *data, int argc, Scheme_Object **argv)
+{
+    Vim_Prim	    *prim = (Vim_Prim *)data;
+    vim_mz_buffer   *buf = NULL;
+    Scheme_Object   *list = NULL;
+    char	    *str = NULL;
+    int		    i, n, size;
+
+    MZ_GC_DECL_REG(1);
+    MZ_GC_VAR_IN_REG(0, list);
+    MZ_GC_REG();
+
+#ifdef HAVE_SANDBOX
+    sandbox_check();
+#endif
+    /*
+     * First of all, we check the type of the supplied MzScheme object.
+     * It must be a string or a list, or the call is in error.
+     */
+    n = SCHEME_INT_VAL(GUARANTEE_INTEGER(prim->name, 0));
+    list = argv[1];
+
+    if (!SCHEME_STRINGP(list) && !SCHEME_PAIRP(list))
+	scheme_wrong_type(prim->name, "string or list", 1, argc, argv);
+    buf = get_buffer_arg(prim->name, 2, argc, argv);
+
+    if (n != 0)	    // 0 can be used in insert
+	check_line_range(n, buf->buf);
+    if (SCHEME_STRINGP(list))
+    {
+	buf_T	    *savebuf = curbuf;
+
+	str = string_to_line(list);
+	curbuf = buf->buf;
+
+	if (u_save((linenr_T)n, (linenr_T)(n+1)) == FAIL)
+	{
+	    curbuf = savebuf;
+	    vim_free(str);
+	    raise_vim_exn(_("cannot save undo information"));
+	}
+	else if (ml_append((linenr_T)n, (char_u *)str, 0, FALSE) == FAIL)
+	{
+	    curbuf = savebuf;
+	    vim_free(str);
+	    raise_vim_exn(_("cannot insert line"));
+	}
+	else
+	{
+	    vim_free(str);
+	    appended_lines_mark((linenr_T)n, 1L);
+	}
+
+	curbuf = savebuf;
+	update_screen(UPD_VALID);
+
+	MZ_GC_UNREG();
+	raise_if_error();
+	return scheme_void;
+    }
+
+    // List
+    size = scheme_proper_list_length(list);
+    MZ_GC_CHECK();
+    if (size < 0)	// improper or cyclic list
+	scheme_wrong_type(prim->name, "proper list",
+		2, argc, argv);
+    else
+    {
+	Scheme_Object   *line = NULL;
+	Scheme_Object   *rest = NULL;
+	char		**array;
+	buf_T		*savebuf = curbuf;
+
+	MZ_GC_DECL_REG(2);
+	MZ_GC_VAR_IN_REG(0, line);
+	MZ_GC_VAR_IN_REG(1, rest);
+	MZ_GC_REG();
+
+	array = ALLOC_CLEAR_MULT(char *, size + 1);
+
+	rest = list;
+	for (i = 0; i < size; ++i)
+	{
+	    line = SCHEME_CAR(rest);
+	    rest = SCHEME_CDR(rest);
+	    array[i] = string_to_line(line);
+	}
+
+	curbuf = buf->buf;
+
+	if (u_save((linenr_T)n, (linenr_T)(n + 1)) == FAIL)
+	{
+	    curbuf = savebuf;
+	    free_array(array);
+	    raise_vim_exn(_("cannot save undo information"));
+	}
+	else
+	{
+	    for (i = 0; i < size; ++i)
+		if (ml_append((linenr_T)(n + i), (char_u *)array[i],
+			    0, FALSE) == FAIL)
+		{
+		    curbuf = savebuf;
+		    free_array(array);
+		    raise_vim_exn(_("cannot insert line"));
+		}
+
+	    if (i > 0)
+		appended_lines_mark((linenr_T)n, (long)i);
+	}
+	free_array(array);
+	MZ_GC_UNREG();
+	curbuf = savebuf;
+	update_screen(UPD_VALID);
+    }
+
+    MZ_GC_UNREG();
+    raise_if_error();
+    return scheme_void;
+}
+
+/*
+ * Predicates
+ */
+/*
+ * (buff? obj)
+ */
+    static Scheme_Object *
+vim_bufferp(void *data UNUSED, int argc UNUSED, Scheme_Object **argv)
+{
+    if (SCHEME_VIMBUFFERP(argv[0]))
+	return scheme_true;
+    else
+	return scheme_false;
+}
+
+/*
+ * (win? obj)
+ */
+    static Scheme_Object *
+vim_windowp(void *data UNUSED, int argc UNUSED, Scheme_Object **argv)
+{
+    if (SCHEME_VIMWINDOWP(argv[0]))
+	return scheme_true;
+    else
+	return scheme_false;
+}
+
+/*
+ * (buff-valid? obj)
+ */
+    static Scheme_Object *
+vim_buffer_validp(void *data UNUSED, int argc UNUSED, Scheme_Object **argv)
+{
+    if (SCHEME_VIMBUFFERP(argv[0])
+	    && ((vim_mz_buffer *)argv[0])->buf != INVALID_BUFFER_VALUE)
+	return scheme_true;
+    else
+	return scheme_false;
+}
+
+/*
+ * (win-valid? obj)
+ */
+    static Scheme_Object *
+vim_window_validp(void *data UNUSED, int argc UNUSED, Scheme_Object **argv)
+{
+    if (SCHEME_VIMWINDOWP(argv[0])
+	    && ((vim_mz_window *)argv[0])->win != INVALID_WINDOW_VALUE)
+	return scheme_true;
+    else
+	return scheme_false;
+}
+
+/*
+ *===========================================================================
+ * Utilities
+ *===========================================================================
+ */
+
+/*
+ * Convert an MzScheme string into a Vim line.
+ *
+ * All internal nulls are replaced by newline characters.
+ * It is an error for the string to contain newline characters.
+ *
+ * Returns pointer to Vim allocated memory
+ */
+    static char *
+string_to_line(Scheme_Object *obj)
+{
+    char	*scheme_str = NULL;
+    char	*vim_str = NULL;
+    OUTPUT_LEN_TYPE	len;
+    int		i;
+
+    scheme_str = scheme_display_to_string(obj, &len);
+
+    // Error checking: String must not contain newlines, as we
+    // are replacing a single line, and we must replace it with
+    // a single line.
+    if (memchr(scheme_str, '\n', len))
+	scheme_signal_error(_("string cannot contain newlines"));
+
+    vim_str = alloc(len + 1);
+
+    // Create a copy of the string, with internal nulls replaced by
+    // newline characters, as is the vim convention.
+    for (i = 0; i < len; ++i)
+    {
+	if (scheme_str[i] == '\0')
+	    vim_str[i] = '\n';
+	else
+	    vim_str[i] = scheme_str[i];
+    }
+
+    vim_str[i] = '\0';
+
+    MZ_GC_CHECK();
+    return vim_str;
+}
+
+#ifdef FEAT_EVAL
+/*
+ * Convert Vim value into MzScheme, adopted from if_python.c
+ */
+    static Scheme_Object *
+vim_to_mzscheme(typval_T *vim_value)
+{
+    Scheme_Object	*result = NULL;
+    // hash table to store visited values to avoid infinite loops
+    Scheme_Hash_Table	*visited = NULL;
+
+    MZ_GC_DECL_REG(2);
+    MZ_GC_VAR_IN_REG(0, result);
+    MZ_GC_VAR_IN_REG(1, visited);
+    MZ_GC_REG();
+
+    visited = scheme_make_hash_table(SCHEME_hash_ptr);
+    MZ_GC_CHECK();
+
+    result = vim_to_mzscheme_impl(vim_value, 1, visited);
+
+    MZ_GC_UNREG();
+    return result;
+}
+
+    static Scheme_Object *
+vim_to_mzscheme_impl(typval_T *vim_value, int depth, Scheme_Hash_Table *visited)
+{
+    Scheme_Object   *result = NULL;
+    int		    new_value = TRUE;
+
+    MZ_GC_DECL_REG(2);
+    MZ_GC_VAR_IN_REG(0, result);
+    MZ_GC_VAR_IN_REG(1, visited);
+    MZ_GC_REG();
+
+    // Avoid infinite recursion
+    if (depth > 100)
+    {
+	MZ_GC_UNREG();
+	return scheme_void;
+    }
+
+    // Check if we run into a recursive loop.  The item must be in visited
+    // then and we can use it again.
+    result = scheme_hash_get(visited, (Scheme_Object *)vim_value);
+    MZ_GC_CHECK();
+    if (result != NULL) // found, do nothing
+	new_value = FALSE;
+    else if (vim_value->v_type == VAR_STRING)
+    {
+	result = scheme_make_byte_string((char *)vim_value->vval.v_string);
+	MZ_GC_CHECK();
+    }
+    else if (vim_value->v_type == VAR_NUMBER)
+    {
+	result = scheme_make_integer((long)vim_value->vval.v_number);
+	MZ_GC_CHECK();
+    }
+    else if (vim_value->v_type == VAR_FLOAT)
+    {
+	result = scheme_make_double((double)vim_value->vval.v_float);
+	MZ_GC_CHECK();
+    }
+    else if (vim_value->v_type == VAR_LIST)
+    {
+	list_T		*list = vim_value->vval.v_list;
+	listitem_T	*curr;
+
+	if (list == NULL || list->lv_first == NULL)
+	    result = scheme_null;
+	else
+	{
+	    Scheme_Object   *obj = NULL;
+
+	    MZ_GC_DECL_REG(1);
+	    MZ_GC_VAR_IN_REG(0, obj);
+	    MZ_GC_REG();
+
+	    curr = list->lv_u.mat.lv_last;
+	    obj = vim_to_mzscheme_impl(&curr->li_tv, depth + 1, visited);
+	    result = scheme_make_pair(obj, scheme_null);
+	    MZ_GC_CHECK();
+
+	    while (curr != list->lv_first)
+	    {
+		curr = curr->li_prev;
+		obj = vim_to_mzscheme_impl(&curr->li_tv, depth + 1, visited);
+		result = scheme_make_pair(obj, result);
+		MZ_GC_CHECK();
+	    }
+	}
+	MZ_GC_UNREG();
+    }
+    else if (vim_value->v_type == VAR_DICT)
+    {
+	Scheme_Object	  *key = NULL;
+	Scheme_Object	  *obj = NULL;
+
+	MZ_GC_DECL_REG(2);
+	MZ_GC_VAR_IN_REG(0, key);
+	MZ_GC_VAR_IN_REG(1, obj);
+	MZ_GC_REG();
+
+	result = (Scheme_Object *)scheme_make_hash_table(SCHEME_hash_ptr);
+	MZ_GC_CHECK();
+	if (vim_value->vval.v_dict != NULL)
+	{
+	    hashtab_T	*ht = &vim_value->vval.v_dict->dv_hashtab;
+	    long_u	todo = ht->ht_used;
+	    hashitem_T	*hi;
+	    dictitem_T	*di;
+
+	    for (hi = ht->ht_array; todo > 0; ++hi)
+	    {
+		if (!HASHITEM_EMPTY(hi))
+		{
+		    --todo;
+
+		    di = dict_lookup(hi);
+		    obj = vim_to_mzscheme_impl(&di->di_tv, depth + 1, visited);
+		    key = scheme_make_byte_string((char *)hi->hi_key);
+		    MZ_GC_CHECK();
+		    scheme_hash_set((Scheme_Hash_Table *)result, key, obj);
+		    MZ_GC_CHECK();
+		}
+	    }
+	}
+	MZ_GC_UNREG();
+    }
+    else if (vim_value->v_type == VAR_FUNC)
+    {
+	Scheme_Object *funcname = NULL;
+
+	MZ_GC_DECL_REG(1);
+	MZ_GC_VAR_IN_REG(0, funcname);
+	MZ_GC_REG();
+
+	// FIXME: func_ref() and func_unref() are needed.
+	funcname = scheme_make_byte_string((char *)vim_value->vval.v_string);
+	MZ_GC_CHECK();
+	result = scheme_make_closed_prim_w_arity(vim_funcref, funcname,
+		(const char *)BYTE_STRING_VALUE(funcname), 0, -1);
+	MZ_GC_CHECK();
+
+	MZ_GC_UNREG();
+    }
+    else if (vim_value->v_type == VAR_PARTIAL)
+    {
+	if (vim_value->vval.v_partial == NULL)
+	    result = scheme_null;
+	else
+	{
+	    Scheme_Object *funcname = NULL;
+
+	    MZ_GC_DECL_REG(1);
+	    MZ_GC_VAR_IN_REG(0, funcname);
+	    MZ_GC_REG();
+
+	    // FIXME: func_ref() and func_unref() are needed.
+	    // TODO: Support pt_dict and pt_argv.
+	    funcname = scheme_make_byte_string(
+			      (char *)partial_name(vim_value->vval.v_partial));
+	    MZ_GC_CHECK();
+	    result = scheme_make_closed_prim_w_arity(vim_funcref, funcname,
+		    (const char *)BYTE_STRING_VALUE(funcname), 0, -1);
+	    MZ_GC_CHECK();
+
+	    MZ_GC_UNREG();
+	}
+    }
+    else if (vim_value->v_type == VAR_BOOL || vim_value->v_type == VAR_SPECIAL)
+    {
+	if (vim_value->vval.v_number <= VVAL_TRUE)
+	    result = scheme_make_integer((long)vim_value->vval.v_number);
+	else
+	    result = scheme_null;
+	MZ_GC_CHECK();
+    }
+    else
+    {
+	result = scheme_void;
+	new_value = FALSE;
+    }
+    if (new_value)
+    {
+	scheme_hash_set(visited, (Scheme_Object *)vim_value, result);
+	MZ_GC_CHECK();
+    }
+    MZ_GC_UNREG();
+    return result;
+}
+
+    static int
+mzscheme_to_vim(Scheme_Object *obj, typval_T *tv)
+{
+    int i, status;
+    Scheme_Hash_Table	*visited = NULL;
+
+    MZ_GC_DECL_REG(2);
+    MZ_GC_VAR_IN_REG(0, obj);
+    MZ_GC_VAR_IN_REG(1, visited);
+    MZ_GC_REG();
+
+    visited = scheme_make_hash_table(SCHEME_hash_ptr);
+    MZ_GC_CHECK();
+
+    status = mzscheme_to_vim_impl(obj, tv, 1, visited);
+    for (i = 0; i < visited->size; ++i)
+    {
+	// free up remembered objects
+	if (visited->vals[i] != NULL)
+	    free_tv((typval_T *)visited->vals[i]);
+    }
+
+    MZ_GC_UNREG();
+    return status;
+}
+    static int
+mzscheme_to_vim_impl(Scheme_Object *obj, typval_T *tv, int depth,
+	Scheme_Hash_Table *visited)
+{
+    int		status = OK;
+    typval_T	*found;
+
+    MZ_GC_DECL_REG(2);
+    MZ_GC_VAR_IN_REG(0, obj);
+    MZ_GC_VAR_IN_REG(1, visited);
+    MZ_GC_REG();
+
+    MZ_GC_CHECK();
+    if (depth > 100) // limit the deepest recursion level
+    {
+	tv->v_type = VAR_NUMBER;
+	tv->vval.v_number = 0;
+	return FAIL;
+    }
+
+    found = (typval_T *)scheme_hash_get(visited, obj);
+    if (found != NULL)
+	copy_tv(found, tv);
+    else if (SCHEME_VOIDP(obj))
+    {
+	tv->v_type = VAR_SPECIAL;
+	tv->vval.v_number = VVAL_NULL;
+    }
+    else if (SCHEME_INTP(obj))
+    {
+	tv->v_type = VAR_NUMBER;
+	tv->vval.v_number = SCHEME_INT_VAL(obj);
+    }
+    else if (SCHEME_BOOLP(obj))
+    {
+	tv->v_type = VAR_BOOL;
+	tv->vval.v_number = SCHEME_TRUEP(obj);
+    }
+    else if (SCHEME_DBLP(obj))
+    {
+	tv->v_type = VAR_FLOAT;
+	tv->vval.v_float = SCHEME_DBL_VAL(obj);
+    }
+    else if (SCHEME_BYTE_STRINGP(obj))
+    {
+	tv->v_type = VAR_STRING;
+	tv->vval.v_string = vim_strsave(BYTE_STRING_VALUE(obj));
+    }
+# if MZSCHEME_VERSION_MAJOR >= 299
+    else if (SCHEME_CHAR_STRINGP(obj))
+    {
+	Scheme_Object *tmp = NULL;
+	MZ_GC_DECL_REG(1);
+	MZ_GC_VAR_IN_REG(0, tmp);
+	MZ_GC_REG();
+
+	tmp = scheme_char_string_to_byte_string(obj);
+	tv->v_type = VAR_STRING;
+	tv->vval.v_string = vim_strsave(BYTE_STRING_VALUE(tmp));
+	MZ_GC_UNREG();
+    }
+#endif
+    else if (SCHEME_VECTORP(obj) || SCHEME_NULLP(obj)
+	    || SCHEME_PAIRP(obj) || SCHEME_MUTABLE_PAIRP(obj))
+    {
+	list_T  *list = list_alloc();
+	if (list == NULL)
+	    status = FAIL;
+	else
+	{
+	    int		    i;
+	    Scheme_Object   *curr = NULL;
+	    Scheme_Object   *cval = NULL;
+	    // temporary var to hold current element of vectors and pairs
+	    typval_T	    *v;
+
+	    MZ_GC_DECL_REG(2);
+	    MZ_GC_VAR_IN_REG(0, curr);
+	    MZ_GC_VAR_IN_REG(1, cval);
+	    MZ_GC_REG();
+
+	    tv->v_type = VAR_LIST;
+	    tv->vval.v_list = list;
+	    ++list->lv_refcount;
+
+	    v = ALLOC_ONE(typval_T);
+	    if (v == NULL)
+		status = FAIL;
+	    else
+	    {
+		// add the value in advance to allow handling of self-referential
+		// data structures
+		typval_T    *visited_tv = ALLOC_ONE(typval_T);
+		copy_tv(tv, visited_tv);
+		scheme_hash_set(visited, obj, (Scheme_Object *)visited_tv);
+
+		if (SCHEME_VECTORP(obj))
+		{
+		    for (i = 0; i < SCHEME_VEC_SIZE(obj); ++i)
+		    {
+			cval = SCHEME_VEC_ELS(obj)[i];
+			status = mzscheme_to_vim_impl(cval, v, depth + 1, visited);
+			if (status == FAIL)
+			    break;
+			status = list_append_tv(list, v);
+			clear_tv(v);
+			if (status == FAIL)
+			    break;
+		    }
+		}
+		else if (SCHEME_PAIRP(obj) || SCHEME_MUTABLE_PAIRP(obj))
+		{
+		    for (curr = obj;
+			    SCHEME_PAIRP(curr) || SCHEME_MUTABLE_PAIRP(curr);
+			    curr = SCHEME_CDR(curr))
+		    {
+			cval = SCHEME_CAR(curr);
+			status = mzscheme_to_vim_impl(cval, v, depth + 1, visited);
+			if (status == FAIL)
+			    break;
+			status = list_append_tv(list, v);
+			clear_tv(v);
+			if (status == FAIL)
+			    break;
+		    }
+		    // improper list not terminated with null
+		    // need to handle the last element
+		    if (status == OK && !SCHEME_NULLP(curr))
+		    {
+			status = mzscheme_to_vim_impl(cval, v, depth + 1, visited);
+			if (status == OK)
+			{
+			    status = list_append_tv(list, v);
+			    clear_tv(v);
+			}
+		    }
+		}
+		// nothing to do for scheme_null
+		vim_free(v);
+	    }
+	    MZ_GC_UNREG();
+	}
+    }
+    else if (SCHEME_HASHTP(obj))
+    {
+	int		i;
+	dict_T		*dict;
+	Scheme_Object   *key = NULL;
+	Scheme_Object   *val = NULL;
+
+	MZ_GC_DECL_REG(2);
+	MZ_GC_VAR_IN_REG(0, key);
+	MZ_GC_VAR_IN_REG(1, val);
+	MZ_GC_REG();
+
+	dict = dict_alloc();
+	if (dict == NULL)
+	    status = FAIL;
+	else
+	{
+	    typval_T    *visited_tv = ALLOC_ONE(typval_T);
+
+	    tv->v_type = VAR_DICT;
+	    tv->vval.v_dict = dict;
+	    ++dict->dv_refcount;
+
+	    copy_tv(tv, visited_tv);
+	    scheme_hash_set(visited, obj, (Scheme_Object *)visited_tv);
+
+	    for (i = 0; i < ((Scheme_Hash_Table *)obj)->size; ++i)
+	    {
+		if (((Scheme_Hash_Table *) obj)->vals[i] != NULL)
+		{
+		    // generate item for `display'ed Scheme key
+		    dictitem_T  *item = dictitem_alloc((char_u *)string_to_line(
+				((Scheme_Hash_Table *) obj)->keys[i]));
+		    // convert Scheme val to Vim and add it to the dict
+		    if (mzscheme_to_vim_impl(((Scheme_Hash_Table *) obj)->vals[i],
+				    &item->di_tv, depth + 1, visited) == FAIL
+			    || dict_add(dict, item) == FAIL)
+		    {
+			dictitem_free(item);
+			status = FAIL;
+			break;
+		    }
+		}
+
+	    }
+	}
+	MZ_GC_UNREG();
+    }
+    else
+    {
+	// `display' any other value to string
+	tv->v_type = VAR_STRING;
+	tv->vval.v_string = (char_u *)string_to_line(obj);
+    }
+    MZ_GC_UNREG();
+    return status;
+}
+
+/*
+ * Scheme prim procedure wrapping Vim funcref
+ */
+    static Scheme_Object *
+vim_funcref(void *name, int argc, Scheme_Object **argv)
+{
+    int i;
+    typval_T args;
+    int status = OK;
+    Scheme_Object *result = NULL;
+    list_T *list = list_alloc();
+
+    MZ_GC_DECL_REG(1);
+    MZ_GC_VAR_IN_REG(0, result);
+    MZ_GC_REG();
+
+    result = scheme_void;
+    if (list == NULL)
+	status = FAIL;
+    else
+    {
+	args.v_type = VAR_LIST;
+	args.vval.v_list = list;
+	++list->lv_refcount;
+	for (i = 0; status == OK && i < argc; ++i)
+	{
+	    typval_T *v = ALLOC_ONE(typval_T);
+	    if (v == NULL)
+		status = FAIL;
+	    else
+	    {
+		status = mzscheme_to_vim(argv[i], v);
+		if (status == OK)
+		{
+		    status = list_append_tv(list, v);
+		    clear_tv(v);
+		}
+		vim_free(v);
+	    }
+	}
+	if (status == OK)
+	{
+	    typval_T ret;
+	    ret.v_type = VAR_UNKNOWN;
+
+	    mzscheme_call_vim(BYTE_STRING_VALUE((Scheme_Object *)name), &args, &ret);
+	    MZ_GC_CHECK();
+	    result = vim_to_mzscheme(&ret);
+	    clear_tv(&ret);
+	    MZ_GC_CHECK();
+	}
+    }
+    clear_tv(&args);
+    MZ_GC_UNREG();
+    if (status != OK)
+	raise_vim_exn(_("error converting Scheme values to Vim"));
+    else
+	raise_if_error();
+    return result;
+}
+
+    void
+do_mzeval(char_u *str, typval_T *rettv)
+{
+    Scheme_Object	*ret = NULL;
+
+    MZ_GC_DECL_REG(1);
+    MZ_GC_VAR_IN_REG(0, ret);
+    MZ_GC_REG();
+
+    if (mzscheme_init())
+    {
+	MZ_GC_UNREG();
+	return;
+    }
+
+    MZ_GC_CHECK();
+    if (eval_with_exn_handling(str, do_eval, &ret) == OK)
+	mzscheme_to_vim(ret, rettv);
+
+    MZ_GC_UNREG();
+}
+#endif
+
+/*
+ * Check to see whether a Vim error has been reported, or a keyboard
+ * interrupt (from vim --> got_int) has been detected.
+ */
+    static int
+vim_error_check(void)
+{
+    return (got_int || did_emsg);
+}
+
+/*
+ * register Scheme exn:vim
+ */
+    static void
+register_vim_exn(void)
+{
+    int	nc = 0;
+    int i;
+    Scheme_Object   *struct_exn = NULL;
+    Scheme_Object   *exn_name = NULL;
+
+    MZ_GC_DECL_REG(2);
+    MZ_GC_VAR_IN_REG(0, struct_exn);
+    MZ_GC_VAR_IN_REG(1, exn_name);
+    MZ_GC_REG();
+
+    exn_name = scheme_intern_symbol("exn:vim");
+    MZ_GC_CHECK();
+    struct_exn = scheme_builtin_value("struct:exn");
+    MZ_GC_CHECK();
+
+    if (vim_exn == NULL)
+	vim_exn = scheme_make_struct_type(exn_name,
+		struct_exn, NULL, 0, 0, NULL, NULL
+#if MZSCHEME_VERSION_MAJOR >= 299
+		, NULL
+#endif
+		);
+
+
+    {
+	Scheme_Object   **tmp = NULL;
+	Scheme_Object   *exn_names[5] = {NULL, NULL, NULL, NULL, NULL};
+	Scheme_Object   *exn_values[5] = {NULL, NULL, NULL, NULL, NULL};
+	MZ_GC_DECL_REG(6);
+	MZ_GC_ARRAY_VAR_IN_REG(0, exn_names, 5);
+	MZ_GC_ARRAY_VAR_IN_REG(3, exn_values, 5);
+	MZ_GC_REG();
+
+	tmp = scheme_make_struct_names(exn_name, scheme_null, 0, &nc);
+	mch_memmove(exn_names, tmp, nc * sizeof(Scheme_Object *));
+	MZ_GC_CHECK();
+
+	tmp = scheme_make_struct_values(vim_exn, exn_names, nc, 0);
+	mch_memmove(exn_values, tmp, nc * sizeof(Scheme_Object *));
+	MZ_GC_CHECK();
+
+	for (i = 0; i < nc; i++)
+	{
+	    scheme_add_global_symbol(exn_names[i],
+		    exn_values[i], environment);
+	    MZ_GC_CHECK();
+	}
+	MZ_GC_UNREG();
+    }
+    MZ_GC_UNREG();
+}
+
+/*
+ * raise exn:vim, may be with additional info string
+ */
+    void
+raise_vim_exn(const char *add_info)
+{
+    char	    *fmt = _("Vim error: ~a");
+    Scheme_Object   *argv[2] = {NULL, NULL};
+    Scheme_Object   *exn = NULL;
+    Scheme_Object   *byte_string = NULL;
+
+    MZ_GC_DECL_REG(5);
+    MZ_GC_ARRAY_VAR_IN_REG(0, argv, 2);
+    MZ_GC_VAR_IN_REG(3, exn);
+    MZ_GC_VAR_IN_REG(4, byte_string);
+    MZ_GC_REG();
+
+    if (add_info != NULL)
+    {
+	char		*c_string = NULL;
+	Scheme_Object   *info = NULL;
+
+	MZ_GC_DECL_REG(3);
+	MZ_GC_VAR_IN_REG(0, c_string);
+	MZ_GC_VAR_IN_REG(2, info);
+	MZ_GC_REG();
+
+	info = scheme_make_byte_string(add_info);
+	MZ_GC_CHECK();
+	c_string = scheme_format_utf8(fmt, (int)STRLEN(fmt), 1, &info, NULL);
+	MZ_GC_CHECK();
+	byte_string = scheme_make_byte_string(c_string);
+	MZ_GC_CHECK();
+	argv[0] = scheme_byte_string_to_char_string(byte_string);
+	SCHEME_SET_IMMUTABLE(argv[0]);
+	MZ_GC_UNREG();
+    }
+    else
+    {
+	byte_string = scheme_make_byte_string(_("Vim error"));
+	MZ_GC_CHECK();
+	argv[0] = scheme_byte_string_to_char_string(byte_string);
+	MZ_GC_CHECK();
+    }
+    MZ_GC_CHECK();
+
+#if MZSCHEME_VERSION_MAJOR < 360
+    argv[1] = scheme_current_continuation_marks();
+    MZ_GC_CHECK();
+#else
+    argv[1] = scheme_current_continuation_marks(NULL);
+    MZ_GC_CHECK();
+#endif
+
+    exn = scheme_make_struct_instance(vim_exn, 2, argv);
+    MZ_GC_CHECK();
+    scheme_raise(exn);
+    MZ_GC_UNREG();
+}
+
+    void
+raise_if_error(void)
+{
+    if (vim_error_check())
+	raise_vim_exn(NULL);
+}
+
+/*
+ * get buffer:
+ * either current
+ * or passed as argv[argnum] with checks
+ */
+    static vim_mz_buffer *
+get_buffer_arg(const char *fname, int argnum, int argc, Scheme_Object **argv)
+{
+    vim_mz_buffer *b;
+
+    if (argc < argnum + 1)
+	return get_vim_curr_buffer();
+    if (!SCHEME_VIMBUFFERP(argv[argnum]))
+	scheme_wrong_type(fname, "vim-buffer", argnum, argc, argv);
+    b = (vim_mz_buffer *)argv[argnum];
+    (void)get_valid_buffer(argv[argnum]);
+    return b;
+}
+
+/*
+ * get window:
+ * either current
+ * or passed as argv[argnum] with checks
+ */
+    static vim_mz_window *
+get_window_arg(const char *fname, int argnum, int argc, Scheme_Object **argv)
+{
+    vim_mz_window *w;
+
+    if (argc < argnum + 1)
+	return get_vim_curr_window();
+    w = (vim_mz_window *)argv[argnum];
+    if (!SCHEME_VIMWINDOWP(argv[argnum]))
+	scheme_wrong_type(fname, "vim-window", argnum, argc, argv);
+    (void)get_valid_window(argv[argnum]);
+    return w;
+}
+
+/*
+ * get valid Vim buffer from Scheme_Object*
+ */
+buf_T *get_valid_buffer(void *obj)
+{
+    buf_T *buf = ((vim_mz_buffer *)obj)->buf;
+
+    if (buf == INVALID_BUFFER_VALUE)
+	scheme_signal_error(_("buffer is invalid"));
+    return buf;
+}
+
+/*
+ * get valid Vim window from Scheme_Object*
+ */
+win_T *get_valid_window(void *obj)
+{
+    win_T *win = ((vim_mz_window *)obj)->win;
+    if (win == INVALID_WINDOW_VALUE)
+	scheme_signal_error(_("window is invalid"));
+    return win;
+}
+
+    int
+mzthreads_allowed(void)
+{
+    return mz_threads_allow;
+}
+
+    static int
+line_in_range(linenr_T lnum, buf_T *buf)
+{
+    return (lnum > 0 && lnum <= buf->b_ml.ml_line_count);
+}
+
+    static void
+check_line_range(linenr_T lnum, buf_T *buf)
+{
+    if (!line_in_range(lnum, buf))
+	scheme_signal_error(_("linenr out of range"));
+}
+
+/*
+ * Check if deleting lines made the cursor position invalid
+ * (or you'll get msg from Vim about invalid linenr).
+ * Changed the lines from "lo" to "hi" and added "extra" lines (negative if
+ * deleted). Got from if_python.c
+ */
+    static void
+mz_fix_cursor(int lo, int hi, int extra)
+{
+    if (curwin->w_cursor.lnum >= lo)
+    {
+	// Adjust the cursor position if it's in/after the changed
+	// lines.
+	if (curwin->w_cursor.lnum >= hi)
+	{
+	    curwin->w_cursor.lnum += extra;
+	    check_cursor_col();
+	}
+	else if (extra < 0)
+	{
+	    curwin->w_cursor.lnum = lo;
+	    check_cursor();
+	}
+	else
+	    check_cursor_col();
+	changed_cline_bef_curs();
+    }
+    invalidate_botline();
+}
+
+static Vim_Prim prims[]=
+{
+    /*
+     * Buffer-related commands
+     */
+    {get_buffer_line, "get-buff-line", 1, 2},
+    {set_buffer_line, "set-buff-line", 2, 3},
+    {get_buffer_line_list, "get-buff-line-list", 2, 3},
+    {get_buffer_name, "get-buff-name", 0, 1},
+    {get_buffer_num, "get-buff-num", 0, 1},
+    {get_buffer_size, "get-buff-size", 0, 1},
+    {set_buffer_line_list, "set-buff-line-list", 3, 4},
+    {insert_buffer_line_list, "insert-buff-line-list", 2, 3},
+    {get_curr_buffer, "curr-buff", 0, 0},
+    {get_buffer_count, "buff-count", 0, 0},
+    {get_next_buffer, "get-next-buff", 0, 1},
+    {get_prev_buffer, "get-prev-buff", 0, 1},
+    {mzscheme_open_buffer, "open-buff", 1, 1},
+    {get_buffer_by_name, "get-buff-by-name", 1, 1},
+    {get_buffer_by_num, "get-buff-by-num", 1, 1},
+    /*
+     * Window-related commands
+     */
+    {get_curr_win, "curr-win", 0, 0},
+    {get_window_count, "win-count", 0, 0},
+    {get_window_by_num, "get-win-by-num", 1, 1},
+    {get_window_num, "get-win-num", 0, 1},
+    {get_window_buffer, "get-win-buffer", 0, 1},
+    {get_window_height, "get-win-height", 0, 1},
+    {set_window_height, "set-win-height", 1, 2},
+    {get_window_width, "get-win-width", 0, 1},
+    {set_window_width, "set-win-width", 1, 2},
+    {get_cursor, "get-cursor", 0, 1},
+    {set_cursor, "set-cursor", 1, 2},
+    {get_window_list, "get-win-list", 0, 1},
+    /*
+     * Vim-related commands
+     */
+    {vim_command, "command", 1, 1},
+    {vim_eval, "eval", 1, 1},
+    {get_range_start, "range-start", 0, 0},
+    {get_range_end, "range-end", 0, 0},
+    {mzscheme_beep, "beep", 0, 0},
+    {get_option, "get-option", 1, 2},
+    {set_option, "set-option", 1, 2},
+    /*
+     * small utilities
+     */
+    {vim_bufferp, "buff?", 1, 1},
+    {vim_windowp, "win?", 1, 1},
+    {vim_buffer_validp, "buff-valid?", 1, 1},
+    {vim_window_validp, "win-valid?", 1, 1}
+};
+
+/*
+ * return MzScheme wrapper for curbuf
+ */
+    static vim_mz_buffer *
+get_vim_curr_buffer(void)
+{
+    if (curbuf->b_mzscheme_ref == NULL)
+	return (vim_mz_buffer *)buffer_new(curbuf);
+    else
+	return BUFFER_REF(curbuf);
+}
+
+/*
+ * return MzScheme wrapper for curwin
+ */
+    static vim_mz_window *
+get_vim_curr_window(void)
+{
+    if (curwin->w_mzscheme_ref == NULL)
+	return (vim_mz_window *)window_new(curwin);
+    else
+	return WINDOW_REF(curwin);
+}
+
+    static void
+make_modules(void)
+{
+    int		    i;
+    Scheme_Env	    *mod = NULL;
+    Scheme_Object   *vimext_symbol = NULL;
+    Scheme_Object   *closed_prim = NULL;
+
+    MZ_GC_DECL_REG(3);
+    MZ_GC_VAR_IN_REG(0, mod);
+    MZ_GC_VAR_IN_REG(1, vimext_symbol);
+    MZ_GC_VAR_IN_REG(2, closed_prim);
+    MZ_GC_REG();
+
+    vimext_symbol = scheme_intern_symbol("vimext");
+    MZ_GC_CHECK();
+    mod = scheme_primitive_module(vimext_symbol, environment);
+    MZ_GC_CHECK();
+    // all prims made closed so they can access their own names
+    for (i = 0; i < (int)ARRAY_LENGTH(prims); i++)
+    {
+	Vim_Prim *prim = prims + i;
+	closed_prim = scheme_make_closed_prim_w_arity(prim->prim, prim, prim->name,
+			    prim->mina, prim->maxa);
+	scheme_add_global(prim->name, closed_prim, mod);
+	MZ_GC_CHECK();
+    }
+    scheme_finish_primitive_module(mod);
+    MZ_GC_CHECK();
+    MZ_GC_UNREG();
+}
+
+#ifdef HAVE_SANDBOX
+static Scheme_Object *M_write = NULL;
+static Scheme_Object *M_read = NULL;
+static Scheme_Object *M_execute = NULL;
+static Scheme_Object *M_delete = NULL;
+
+    static void
+sandbox_check(void)
+{
+    if (sandbox)
+	raise_vim_exn(_("not allowed in the Vim sandbox"));
+}
+
+/*
+ * security guards to force Vim's sandbox restrictions on MzScheme level
+ */
+    static Scheme_Object *
+sandbox_file_guard(int argc UNUSED, Scheme_Object **argv)
+{
+    if (!sandbox)
+	return scheme_void;
+
+    Scheme_Object *requested_access = argv[2];
+
+    if (M_write == NULL)
+    {
+	MZ_REGISTER_STATIC(M_write);
+	M_write = scheme_intern_symbol("write");
+	MZ_GC_CHECK();
+    }
+    if (M_read == NULL)
+    {
+	MZ_REGISTER_STATIC(M_read);
+	M_read = scheme_intern_symbol("read");
+	MZ_GC_CHECK();
+    }
+    if (M_execute == NULL)
+    {
+	MZ_REGISTER_STATIC(M_execute);
+	M_execute = scheme_intern_symbol("execute");
+	MZ_GC_CHECK();
+    }
+    if (M_delete == NULL)
+    {
+	MZ_REGISTER_STATIC(M_delete);
+	M_delete = scheme_intern_symbol("delete");
+	MZ_GC_CHECK();
+    }
+
+    while (!SCHEME_NULLP(requested_access))
+    {
+	Scheme_Object *item = SCHEME_CAR(requested_access);
+	if (scheme_eq(item, M_write) || scheme_eq(item, M_read)
+		|| scheme_eq(item, M_execute) || scheme_eq(item, M_delete))
+	    raise_vim_exn(_("not allowed in the Vim sandbox"));
+	requested_access = SCHEME_CDR(requested_access);
+    }
+
+    return scheme_void;
+}
+
+    static Scheme_Object *
+sandbox_network_guard(int argc UNUSED, Scheme_Object **argv UNUSED)
+{
+    return scheme_void;
+}
+#endif
+
+#endif