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-rw-r--r-- | web/server/h2o/libh2o/deps/mruby/doc/guides/mrbconf.md | 146 | ||||
-rw-r--r-- | web/server/h2o/libh2o/deps/mruby/doc/guides/mrbgems.md | 340 | ||||
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diff --git a/web/server/h2o/libh2o/deps/mruby/doc/guides/compile.md b/web/server/h2o/libh2o/deps/mruby/doc/guides/compile.md deleted file mode 100644 index 2aaf6f1fe..000000000 --- a/web/server/h2o/libh2o/deps/mruby/doc/guides/compile.md +++ /dev/null @@ -1,488 +0,0 @@ -# Compile - -mruby uses Rake to compile and cross-compile all libraries and -binaries. - -## Prerequisites - -To compile mruby out of the source code you need the following tools: -* C Compiler (i.e. ```gcc```) -* Linker (i.e. ```gcc```) -* Archive utility (i.e. ```ar```) -* Parser generator (i.e. ```bison```) -* Ruby 1.8 or 1.9 (i.e. ```ruby``` or ```jruby```) - -Optional: -* GIT (to update mruby source and integrate mrbgems easier) -* C++ compiler (to use GEMs which include \*.cpp, \*.cxx, \*.cc) -* Assembler (to use GEMs which include \*.asm) - -## Usage - -Inside of the root directory of the mruby source a file exists -called *build_config.rb*. This file contains the build configuration -of mruby and looks like this for example: -```ruby -MRuby::Build.new do |conf| - toolchain :gcc -end -``` - -All tools necessary to compile mruby can be set or modified here. In case -you want to maintain an additional *build_config.rb* you can define a -customized path using the *$MRUBY_CONFIG* environment variable. - -To compile just call ```./minirake``` inside of the mruby source root. To -generate and execute the test tools call ```./minirake test```. To clean -all build files call ```./minirake clean```. To see full command line on -build, call ```./minirake -v```. - -## Build Configuration - -Inside of the *build_config.rb* the following options can be configured -based on your environment. - -### Toolchains - -The mruby build system already contains a set of toolchain templates which -configure the build environment for specific compiler infrastructures. - -#### GCC - -Toolchain configuration for the GNU C Compiler. -```ruby -toolchain :gcc -``` - -#### clang - -Toolchain configuration for the LLVM C Compiler clang. Mainly equal to the -GCC toolchain. -```ruby -toolchain :clang -``` - -#### Visual Studio 2010, 2012 and 2013 - -Toolchain configuration for Visual Studio on Windows. If you use the -[Visual Studio Command Prompt](http://msdn.microsoft.com/en-us/library/ms229859\(v=vs.110\).aspx), -you normally do not have to specify this manually, since it gets automatically detected by our build process. -```ruby -toolchain :visualcpp -``` - -#### Android - -Toolchain configuration for Android. -```ruby -toolchain :android -``` - -Requires the custom standalone Android NDK and the toolchain path -in ```ANDROID_STANDALONE_TOOLCHAIN```. - -### Binaries - -It is possible to select which tools should be compiled during the compilation -process. The following tools can be selected: -* mruby (mruby interpreter) -* mirb (mruby interactive shell) - -To select them declare conf.gem as follows: -```ruby -conf.gem "#{root}/mrbgems/mruby-bin-mruby" -conf.gem "#{root}/mrbgems/mruby-bin-mirb" -``` - -### File Separator - -Some environments require a different file separator character. It is possible to -set the character via ```conf.file_separator```. -```ruby -conf.file_separator = '/' -``` - -### C Compiler - -Configuration of the C compiler binary, flags and include paths. -```ruby -conf.cc do |cc| - cc.command = ... - cc.flags = ... - cc.include_paths = ... - cc.defines = ... - cc.option_include_path = ... - cc.option_define = ... - cc.compile_options = ... -end -``` - -C Compiler has header searcher to detect installed library. - -If you need a include path of header file use ```search_header_path```: -```ruby -# Searches ```iconv.h```. -# If found it will return include path of the header file. -# Otherwise it will return nil . -fail 'iconv.h not found' unless conf.cc.search_header_path 'iconv.h' -``` - -If you need a full file name of header file use ```search_header```: -```ruby -# Searches ```iconv.h```. -# If found it will return full path of the header file. -# Otherwise it will return nil . -iconv_h = conf.cc.search_header 'iconv.h' -print "iconv.h found: #{iconv_h}\n" -``` - -Header searcher uses compiler's ```include_paths``` by default. -When you are using GCC toolchain (including clang toolchain since its base is gcc toolchain) -it will use compiler specific include paths too. (For example ```/usr/local/include```, ```/usr/include```) - -If you need a special header search paths define a singleton method ```header_search_paths``` to C compiler: -```ruby -def conf.cc.header_search_paths - ['/opt/local/include'] + include_paths -end -``` - -### Linker - -Configuration of the Linker binary, flags and library paths. -```ruby -conf.linker do |linker| - linker.command = ... - linker.flags = ... - linker.flags_before_libraries = ... - linker.libraries = ... - linker.flags_after_libraries = ... - linker.library_paths = .... - linker.option_library = ... - linker.option_library_path = ... - linker.link_options = ... -end -``` - -### Archiver - -Configuration of the Archiver binary and flags. -```ruby -conf.archiver do |archiver| - archiver.command = ... - archiver.archive_options = ... -end -``` - -### Parser Generator - -Configuration of the Parser Generator binary and flags. -```ruby -conf.yacc do |yacc| - yacc.command = ... - yacc.compile_options = ... -end -``` - -### GPerf - -Configuration of the GPerf binary and flags. -```ruby -conf.gperf do |gperf| - gperf.command = ... - gperf.compile_options = ... -end -``` - -### File Extensions -```ruby -conf.exts do |exts| - exts.object = ... - exts.executable = ... - exts.library = ... -end -``` - -### Mrbgems - -Integrate GEMs in the build process. -```ruby -# Integrate GEM with additional configuration -conf.gem 'path/to/gem' do |g| - g.cc.flags << ... -end - -# Integrate GEM without additional configuration -conf.gem 'path/to/another/gem' -``` - -See doc/mrbgems/README.md for more option about mrbgems. - -### Mrbtest - -Configuration Mrbtest build process. - -If you want mrbtest.a only, You should set ```conf.build_mrbtest_lib_only``` -```ruby -conf.build_mrbtest_lib_only -``` - -### Bintest - -Tests for mrbgem tools using CRuby. -To have bintests place \*.rb scripts to ```bintest/``` directory of mrbgems. -See ```mruby-bin-*/bintest/*.rb``` if you need examples. -If you want a temporary files use `tempfile` module of CRuby instead of ```/tmp/```. - -You can enable it with following: -```ruby -conf.enable_bintest -``` - -### C++ ABI - -By default, mruby uses setjmp/longjmp to implement its -exceptions. But it doesn't release C++ stack object -correctly. To support mrbgems written in C++, mruby can be -configured to use C++ exception. - -There are two levels of C++ exception handling. The one is -```enable_cxx_exception``` that enables C++ exception, but -uses C ABI. The other is ```enable_cxx_abi``` where all -files are compiled by C++ compiler. - -When you mix C++ code, C++ exception would be enabled automatically. -If you need to enable C++ exception explicitly add the following: -```ruby -conf.enable_cxx_exception -``` - -#### C++ exception disabling. - -If your compiler does not support C++ and you want to ensure -you don't use mrbgem written in C++, you can explicitly disable -C++ exception, add following: -```ruby -conf.disable_cxx_exception -``` -and you will get an error when you try to use C++ gem. -Note that it must be called before ```enable_cxx_exception``` or ```gem``` method. - -### Debugging mode - -To enable debugging mode add the following: -```ruby -conf.enable_debug -``` - -When debugging mode is enabled -* Macro ```MRB_DEBUG``` would be defined. - * Which means ```mrb_assert()``` macro is enabled. -* Debug information of irep would be generated by ```mrbc```. - * Because ```-g``` flag would be added to ```mrbc``` runner. - * You can have better backtrace of mruby scripts with this. - -## Cross-Compilation - -mruby can also be cross-compiled from one platform to another. To -achieve this the *build_config.rb* needs to contain an instance of -```MRuby::CrossBuild```. This instance defines the compilation -tools and flags for the target platform. An example could look -like this: -```ruby -MRuby::CrossBuild.new('32bit') do |conf| - toolchain :gcc - - conf.cc.flags << "-m32" - conf.linker.flags << "-m32" -end -``` - -All configuration options of ```MRuby::Build``` can also be used -in ```MRuby::CrossBuild```. - -### Mrbtest in Cross-Compilation - -In cross compilation, you can run ```mrbtest``` on emulator if -you have it by changing configuration of test runner. -```ruby -conf.test_runner do |t| - t.command = ... # set emulator. this value must be non nil or false - t.flags = ... # set flags of emulator - - def t.run(bin) # override `run` if you need to change the behavior of it - ... # `bin` is the full path of mrbtest - end -end -``` - -## Build process - -During the build process the directory *build* will be created in the -root directory. The structure of this directory will look like this: - - +- build - | - +- host - | - +- bin <- Binaries (mirb, mrbc and mruby) - | - +- lib <- Libraries (libmruby.a and libmruby_core.a) - | - +- mrblib - | - +- src - | - +- test <- mrbtest tool - | - +- tools - | - +- mirb - | - +- mrbc - | - +- mruby - -The compilation workflow will look like this: -* compile all files under *src* (object files will be stored -in *build/host/src*) -* generate parser grammar out of *src/parse.y* (generated -result will be stored in *build/host/src/y.tab.c*) -* compile *build/host/src/y.tab.c* to *build/host/src/y.tab.o* -* create *build/host/lib/libmruby_core.a* out of all object files (C only) -* create ```build/host/bin/mrbc``` by compiling *tools/mrbc/mrbc.c* and -linking with *build/host/lib/libmruby_core.a* -* create *build/host/mrblib/mrblib.c* by compiling all \*.rb files -under *mrblib* with ```build/host/bin/mrbc``` -* compile *build/host/mrblib/mrblib.c* to *build/host/mrblib/mrblib.o* -* create *build/host/lib/libmruby.a* out of all object files (C and Ruby) -* create ```build/host/bin/mruby``` by compiling *mrbgems/mruby-bin-mruby/tools/mruby/mruby.c* and -linking with *build/host/lib/libmruby.a* -* create ```build/host/bin/mirb``` by compiling *mrbgems/mruby-bin-mirb/tools/mirb/mirb.c* and -linking with *build/host/lib/libmruby.a* - -``` - _____ _____ ______ ____ ____ _____ _____ ____ -| CC |->|GEN |->|AR |->|CC |->|CC |->|AR |->|CC |->|CC | -| *.c | |y.tab| |core.a| |mrbc| |*.rb| |lib.a| |mruby| |mirb| - ----- ----- ------ ---- ---- ----- ----- ---- -``` - -### Cross-Compilation - -In case of a cross-compilation to *i386* the *build* directory structure looks -like this: - - +- build - | - +- host - | | - | +- bin <- Native Binaries - | | - | +- lib <- Native Libraries - | | - | +- mrblib - | | - | +- src - | | - | +- test <- Native mrbtest tool - | | - | +- tools - | | - | +- mirb - | | - | +- mrbc - | | - | +- mruby - +- i386 - | - +- bin <- Cross-compiled Binaries - | - +- lib <- Cross-compiled Libraries - | - +- mrblib - | - +- src - | - +- test <- Cross-compiled mrbtest tool - | - +- tools - | - +- mirb - | - +- mrbc - | - +- mruby - -An extra directory is created for the target platform. In case you -compile for *i386* a directory called *i386* is created under the -build directory. - -The cross compilation workflow starts in the same way as the normal -compilation by compiling all *native* libraries and binaries. -Afterwards the cross compilation process proceeds like this: -* cross-compile all files under *src* (object files will be stored -in *build/i386/src*) -* generate parser grammar out of *src/parse.y* (generated -result will be stored in *build/i386/src/y.tab.c*) -* cross-compile *build/i386/src/y.tab.c* to *build/i386/src/y.tab.o* -* create *build/i386/mrblib/mrblib.c* by compiling all \*.rb files -under *mrblib* with the native ```build/host/bin/mrbc``` -* cross-compile *build/host/mrblib/mrblib.c* to *build/host/mrblib/mrblib.o* -* create *build/i386/lib/libmruby.a* out of all object files (C and Ruby) -* create ```build/i386/bin/mruby``` by cross-compiling *mrbgems/mruby-bin-mruby/tools/mruby/mruby.c* and -linking with *build/i386/lib/libmruby.a* -* create ```build/i386/bin/mirb``` by cross-compiling *mrbgems/mruby-bin-mirb/tools/mirb/mirb.c* and -linking with *build/i386/lib/libmruby.a* -* create *build/i386/lib/libmruby_core.a* out of all object files (C only) -* create ```build/i386/bin/mrbc``` by cross-compiling *tools/mrbc/mrbc.c* and -linking with *build/i386/lib/libmruby_core.a* - -``` - _______________________________________________________________ -| Native Compilation for Host System | -| _____ ______ _____ ____ ____ _____ | -| | CC | -> |AR | -> |GEN | -> |CC | -> |CC | -> |AR | | -| | *.c | |core.a| |y.tab| |mrbc| |*.rb| |lib.a| | -| ----- ------ ----- ---- ---- ----- | - --------------------------------------------------------------- - || - \||/ - \/ - ________________________________________________________________ -| Cross Compilation for Target System | -| _____ _____ _____ ____ ______ _____ | -| | CC | -> |AR | -> |CC | -> |CC | -> |AR | -> |CC | | -| | *.c | |lib.a| |mruby| |mirb| |core.a| |mrbc | | -| ----- ----- ----- ---- ------ ----- | - ---------------------------------------------------------------- -``` - -## Build Configuration Examples - -### Minimal Library - -To build a minimal mruby library you need to use the Cross Compiling -feature due to the reason that there are functions (i.e. stdio) which -can't be disabled for the main build. - -```ruby -MRuby::CrossBuild.new('Minimal') do |conf| - toolchain :gcc - - conf.cc.defines = %w(MRB_DISABLE_STDIO) - conf.bins = [] -end -``` - -This configuration defines a cross compile build called 'Minimal' which -is using the GCC and compiles for the host machine. It also disables -all usages of stdio and doesn't compile any binaries (i.e. mrbc). - -## Test Environment - -mruby's build process includes a test environment. In case you start the testing -of mruby, a native binary called ```mrbtest``` will be generated and executed. -This binary contains all test cases which are defined under *test/t*. In case -of a cross-compilation an additional cross-compiled *mrbtest* binary is -generated. You can copy this binary and run on your target system. diff --git a/web/server/h2o/libh2o/deps/mruby/doc/guides/debugger.md b/web/server/h2o/libh2o/deps/mruby/doc/guides/debugger.md deleted file mode 100644 index 72f2c2b32..000000000 --- a/web/server/h2o/libh2o/deps/mruby/doc/guides/debugger.md +++ /dev/null @@ -1,370 +0,0 @@ -# How to Use the mruby Debugger - -copyright (c) 2014 Specified Non-Profit Corporation mruby Forum - -## 1. Summary - -This file documents the mruby debugger ('mrdb') methods. - -## 2 Debugging with mrdb - -## 2.1 Building mrdb - -The trunk of the mruby source tree, with the most recent mrdb, can be checked out with the following command: - -```bash -$ git clone https://github.com/mruby/mruby.git -``` - -To run the `make` command: - -```bash -$ cd mruby -$ make -``` - -By default, the `make` command will install the debugger files into mruby/bin. - -You can add the path for mrdb on your host environment with the following command: - -```bash -$ echo "export PATH=\$PATH:MRUBY_ROOT/bin" >> ~/.bashrc -$ source ~/.bashrc -``` - -`*MRUBY_ROOT` is the directory in which mruby source code will be installed. - -To confirm mrdb was installed properly, run mrdb with the `--version` option: - -```bash -$ mrdb --version -mruby 1.3.0 (2017-7-4) -``` - -## 2.2 Basic Operation - -### 2.2.1 Debugging mruby Script Files (rb file) with mrdb - -To invoke the mruby debugger, just type `mrdb`. - -To specify the script file: - -```bash -$ mrdb [option] file name -``` - -For example: Debugging sample.rb - -```bash -$ mrdb sample.rb -``` - -You can execute the shell commands listed below: - -|command|description| -|:-:|:--| -|run|execute programs| -|step|execute stepping| -|continue|execute continuing program| -|break|configure the breaking point| -|delete|deleting the breaking points| -|disable|disabling the breaking points| -|enable|enabling the breaking points| -|info breakpoints|showing list of the breaking points| -|print|evaluating and printing the values of the mruby expressions in the script| -|list|displaying the source cords| -|help|showing help| -|quit|terminating the mruby debugger| - -### 2.2.2 Debugging mruby Binary Files (mrb file) with mrdb - -You can debug the mruby binary files. - -#### 2.2.2.1 Debugging the binary files - -* notice -To debug mruby binary files, you need to compile mruby files with option `-g`. - -```bash -$ mrbc -g sample.rb -``` - -You can debug the mruby binary files with following command and the option `-b`. - -```bash -$ mrdb -b sample.mrb -``` - -Then you can execute all debugger shell commands. - -#### Break Command - -You can use any breakpoint to stop the program by specifying the line number and method name. -The breakpoint list will be displayed after you have set the breakpoint successfully. - -Usage: - -``` -break [file:]linenum -b [file:]linenum -break [class:]method -b [class:]method -``` - -The breakpoint will be ordered in serial from 1. -The number, which was given to the deleted breakpoint, will never be given to another breakpoint again. - -You can give multiple breakpoints to specified the line number and method. -Be ware that breakpoint command will not check the validity of the class name and method name. - -You can get the current breakpoint information by the following options. - -breakpoint breakpoint number : file name. line number - -breakpoint breakpoint number : [class name,] method name - -#### Continue Command - -Usage: - -``` -continue [N] -c [N] -``` - -N: the next breakpoint number - -When resuming the program, it will stop at breakpoint N (N-1 breakpoint will be ignored). - -When you run the `continue` command without specifying N, the program will be stopped at the next breakpoint. - -Example: - -``` -(foo.rb:1) continue 3 -``` - -This will resume the program and stop it at the third breakpoint. - -#### Delete Command - -This will delete the specified breakpoint. - -Usage: - -``` -delete [breakpoint-no] -d [breakpoint-no] -``` - -breakpoint-no: breakpoint number - -Example: - -``` -(foo.rb:1) delete -``` - -This will delete all of the breakpoints. - -``` -(foo.rb:1) delete 1 3 -``` - -This will delete the breakpoint at 1 and 3. - -#### Disable Command - -This will disable the specified breakpoint. - -Usage: - -``` -disable [breakpoint-no] -dis [breakpoint-no] -``` - -reappointing: breakpoint number - -Example: - -``` -(foo.rb:1) disable -``` - -Use `disable` if you would like to disable all of the breakpoints. - -``` -(foo.rb:1) disable 1 3 -``` - -This will disable the breakpoints at 1 and 3. - -#### Enable Command - -This will enable the specified breakpoints. - -Usage: - -``` -enable [breakpoint-no] -e [breakpoint-no] -``` - -breakpoint-no: breakpoint number - -Example: - -``` -(foo.rb:1) enable -``` - -Enabling all breakpoints -``` -(foo.rb:1) enable 1 3 -``` - -Enabling the breakpoint 1 and 3 - -#### eval command - -Evaluating the string as source code and printing the value. - -Same as print command, please see print command. - -#### help command - -Displaying the help message. - -Usage: - -``` -help [command] -h [command] -``` - -Typing `help` without any options will display the command list. - -#### Info Breakpoints Command - -Displaying the specified breakpoint information. - -Usage: - -``` -info breakpoints [breakpoint-no] -i b [breakpoint-no] -``` - -breakpoint-no: breakpoint number - -Typing "info breakpoints" without ant option will display all breakpoint information. -Example: - -``` -(sample.rb:1) info breakpoints -Num Type Enb What -1 breakpoint y at sample.rb:3 -> file name,line number -2 breakpoint n in Sample_class:sample_class_method -> [class:]method name -3 breakpoint y in sample_global_method -``` - -Displaying the specified breakpoint number: - -``` -(foo.rb:1) info breakpoints 1 3 -Num Type Enb What -1 breakpoint y at sample.rb:3 -3 breakpoint y in sample_global_method -``` - -#### List Command - -To display the code of the source file. - -Usage: - -``` -list [filename:]first[,last] -l [filename]:first[,last] -``` - -first: the opening row number -last : the closing row number - -When you specify the `first`, but not the `last` option, you will receive 10 rows. -When you do not specify both the `first` and `last` options, you will receive the next 10 rows. - -Example: - -``` -Specifying file name and first row number -sample.rb:1) list sample2.rb:5 -``` - -Specifying the file name and the first and last row number: - -``` -(sample.rb:1) list sample2.rb:6,7 -``` - -#### Print Command - -Evaluating the string as source code and printing the value. - -Usage: - -``` -print [expr] -p [expr] -``` - -expr: expression - -The expression is mandatory. -The displayed expressions will be serially ordered from 1. -If an exception occurs, the exception information will be displayed and the debugging will be continued. - -Example: - -``` -(sample.rb:1) print 1+2 -$1 = 3 -(sample.rb:1) print self -$2 = main -``` - -Below is the case of the exception: - -``` -(sample.rb:1) print (1+2 -$1 = SyntaxError: line 1: syntax error, unexpected $end, expecting ')' -``` - -#### Quit Command - -Quitting the debugger. - -Usage: - -``` -quit -q -``` - -#### Run Command - -Running the program and stopping at the first breakpoint. - -Usage: - -``` -run -r -``` - -#### Step Command - -This will run the program step by step. -When the method and the block are invoked, the program will be stop at the first row. -The program, which is developed in C, will be ignored. diff --git a/web/server/h2o/libh2o/deps/mruby/doc/guides/gc-arena-howto.md b/web/server/h2o/libh2o/deps/mruby/doc/guides/gc-arena-howto.md deleted file mode 100644 index aff7360e9..000000000 --- a/web/server/h2o/libh2o/deps/mruby/doc/guides/gc-arena-howto.md +++ /dev/null @@ -1,177 +0,0 @@ -# How to use `mrb_gc_arena_save()`/`mrb_gc_arena_restore()`/`mrb_gc_protect()` - -_This is an English translation of [Matz's blog post][matz blog post] -written in Japanese._ -_Some parts are updated to reflect recent changes._ -[matz blog post]: http://www.rubyist.net/~matz/20130731.html - -When you are extending mruby using C language, you may encounter -mysterious "arena overflow error" or memory leak or very slow -execution speed. This is an error indicating overflow of "GC arena" -implementing "conservative GC". - -GC (garbage collector) must ensure that object is "alive", in other -words, that it is referenced by somewhere from program. This can be -determined by checking if the object can be directly or indirectly -referenced by root. The local variables, global variables and -constants etc are root. - -If program execution is performed inside mruby VM, there is nothing to -worry about because GC can access all roots owned by VM. - -The problem arises when executing C functions. The object referenced -by C variable is also "alive", but mruby GC cannot aware of this, so -it might mistakenly recognize the objects referenced by only C -variables as dead. - -This can be a fatal bug if the GC tries to collect a live object. - -In CRuby, we scan C stack area, and use C variable as root to check -whether object is alive or not. Of course, because we are accessing C -stack just as memory region, we never know it is an integer or a -pointer. We workaround this by assuming that if it looks like a -pointer, then assume it as a pointer. We call it "conservative". - -By the way, CRuby's "conservative GC" has some problems. - -The biggest problem is we have no way to access to the stack area in -portable way. Therefore, we cannot use this method if we'd like to -implement highly portable runtime, like mruby. - -So we came up with an another plan to implement "conservative GC" in mruby. - -Again, the problem is when an object which was created in C function, becomes -no longer referenced in the Ruby world, and cannot be treated as garbage. - -In mruby, we recognize all objects created in C function are alive. -Then we have no problem such as confusing a live object as dead. - -This means that because we cannot collect truly dead object, we may -lose efficiency, but as a trade-off the GC itself is highly portable. -We can say goodbye to the problem that GC deletes live objects due to -optimization which sometimes occurs in CRuby. - -According to this idea, we have a table, called "GC arena", which -remembers objects created in C function. - -The arena is stack structure, when C function execution is returned to mruby -VM, all objects registered in the arena are popped. - -This works very well, but can cause another problem: "arena overflow error" or -memory leak. - -As of this writing, mruby automatically extend arena to remember -objects (See `MRB_GC_FIXED_ARENA` and `MRB_GC_ARENA_SIZE` in -doc/guides/mrbconf.md). - -If you create many objects in C functions, memory usage will increase, since -GC never kick in. This memory usage may look like memory leak, but will also -make execution slower as more memory will need to be allocated. - -With the build time configuration, you can limit the maximum size of -arena (e.g., 100). Then if you create many objects, arena overflows, -thus you will get an "arena overflow error". - -To workaround these problems, we have `mrb_gc_arena_save()` and -`mrb_gc_arena_restore()` functions. - -`int mrb_gc_arena_save(mrb)` returns the current position of the stack -top of GC arena, and `void mrb_gc_arena_restore(mrb, idx)` sets the -stack top position to back to given `idx`. - -We can use them like this: - -```c -int arena_idx = mrb_gc_arena_save(mrb); - -// ...create objects... -mrb_gc_arena_restore(mrb, arena_idx); - -``` - -In mruby, C function calls are surrounded by this save/restore, but we -can further optimize memory usage by surrounding save/restore, and can -avoid creating arena overflow bugs. - -Let's take a real example. Here is the source code of `Array#inspect`: - -```c -static mrb_value -inspect_ary(mrb_state *mrb, mrb_value ary, mrb_value list) -{ - mrb_int i; - mrb_value s, arystr; - char head[] = { '[' }; - char sep[] = { ',', ' ' }; - char tail[] = { ']' }; - - /* check recursive */ - for(i=0; i<RARRAY_LEN(list); i++) { - if (mrb_obj_equal(mrb, ary, RARRAY_PTR(list)[i])) { - return mrb_str_new(mrb, "[...]", 5); - } - } - - mrb_ary_push(mrb, list, ary); - - arystr = mrb_str_new_capa(mrb, 64); - mrb_str_cat(mrb, arystr, head, sizeof(head)); - - for(i=0; i<RARRAY_LEN(ary); i++) { - int ai = mrb_gc_arena_save(mrb); - - if (i > 0) { - mrb_str_cat(mrb, arystr, sep, sizeof(sep)); - } - if (mrb_array_p(RARRAY_PTR(ary)[i])) { - s = inspect_ary(mrb, RARRAY_PTR(ary)[i], list); - } - else { - s = mrb_inspect(mrb, RARRAY_PTR(ary)[i]); - } - mrb_str_cat(mrb, arystr, RSTRING_PTR(s), RSTRING_LEN(s)); - mrb_gc_arena_restore(mrb, ai); - } - - mrb_str_cat(mrb, arystr, tail, sizeof(tail)); - mrb_ary_pop(mrb, list); - - return arystr; -} -``` - -This is a real example, so a little bit complicated, but bear with me. -The essence of `Array#inspect` is that after stringifying each element -of array using `inspect` method, we join them together so that we can -get `inspect` representation of the entire array. - -After the `inspect` representation is created, we no longer require the -individual string representation. This means that we don't have to register -these temporal objects into GC arena. - -Therefore, in order to keep the arena size small; the `ary_inspect()` function -will do the following: - -* save the position of the stack top using `mrb_gc_arena_save()`. -* get `inspect` representation of each element. -* append it to the constructing entire `inspect` representation of array. -* restore stack top position using `mrb_gc_arena_restore()`. - -Please note that the final `inspect` representation of entire array -was created before the call of `mrb_gc_arena_restore()`. Otherwise, -required temporal object may be deleted by GC. - -We may have a usecase where after creating many temporal objects, we'd -like to keep some of them. In this case, we cannot use the same idea -in `ary_inspect()` like appending objects to existing one. -Instead, after `mrb_gc_arena_restore()`, we must re-register the objects we -want to keep in the arena using `mrb_gc_protect(mrb, obj)`. -Use `mrb_gc_protect()` with caution because it could also lead to an "arena -overflow error". - -We must also mention that when `mrb_funcall` is called in top level, the return -value is also registered to GC arena, so repeated use of `mrb_funcall` may -eventually lead to an "arena overflow error". - -Use `mrb_gc_arena_save()` and `mrb_gc_arena_restore()` or possible use of -`mrb_gc_protect()` to workaround this. diff --git a/web/server/h2o/libh2o/deps/mruby/doc/guides/mrbconf.md b/web/server/h2o/libh2o/deps/mruby/doc/guides/mrbconf.md deleted file mode 100644 index f957f8ce2..000000000 --- a/web/server/h2o/libh2o/deps/mruby/doc/guides/mrbconf.md +++ /dev/null @@ -1,146 +0,0 @@ -# mruby configuration macros. - -## How to use these macros. -You can use mrbconfs with following ways: -* Write them in `mrbconf.h`. - * Using compiler flags is preferred when building a cross binaries or multiple mruby binaries - since it's easier to use different mrbconf per each `MRuby::Build`. - * Most flags can be enabled by just commenting in. -* Pass them as compiler flags. - * Make sure you pass the same flags to all compilers since some mrbconf(e.g., `MRB_GC_FIXED_ARENA`) - changes `struct` layout and cause memory access error when C and other language(e.g., C++) is mixed. - -## stdio setting. -`MRB_DISABLE_STDIO` -* When defined `<stdio.h>` functions won't be used. -* Some features will be disabled when this is enabled: - * `mrb_irep` load/dump from/to file. - * Compiling mruby script from file. - * Printing features in **src/print.c**. - -## Debug macros. -`MRB_ENABLE_DEBUG_HOOK` -* When defined code fetch hook and debug OP hook will be enabled. -* When using any of the hook set function pointer `code_fetch_hook` and/or `debug_op_hook` of `mrb_state`. -* Fetch hook will be called before any OP. -* Debug OP hook will be called when dispatching `OP_DEBUG`. - -`MRB_DEBUG` -* When defined `mrb_assert*` macro will be defined with macros from `<assert.h>`. -* Could be enabled via `enable_debug` method of `MRuby::Build`. - -## Stack configuration - -`MRB_STACK_EXTEND_DOUBLING` -* If defined doubles the stack size when extending it. -* Else extends stack with `MRB_STACK_GROWTH`. - -`MRB_STACK_GROWTH` -* Default value is `128`. -* Used in stack extending. -* Ignored when `MRB_STACK_EXTEND_DOUBLING` is defined. - -`MRB_STACK_MAX` -* Default value is `0x40000 - MRB_STACK_GROWTH`. -* Raises `RuntimeError` when stack size exceeds this value. - -## Primitive type configuration. - -`MRB_USE_FLOAT` -* When defined single precision floating point type(C type `float`) is used as `mrb_float`. -* Else double precision floating point type(C type `double`) is used as `mrb_float`. - -`MRB_INT16` -* When defined `int16_t` will be defined as `mrb_int`. -* Conflicts with `MRB_INT64`. - -`MRB_INT64` -* When defined `int64_t` will be defined as `mrb_int`. -* Conflicts with `MRB_INT16`. -* When `MRB_INT16` or `MRB_INT64` isn't defined `int`(most of the times 32-bit integer) -will be defined as `mrb_int`. - -## Garbage collector configuration. - -`MRB_GC_STRESS` -* When defined full GC is emitted per each `RBasic` allocation. -* Mainly used in memory manager debugging. - -`MRB_GC_TURN_OFF_GENERATIONAL` -* When defined turns generational GC by default. - -`MRB_GC_FIXED_ARENA` -* When defined used fixed size GC arena. -* Raises `RuntimeError` when this is defined and GC arena size exceeds `MRB_GC_ARENA_SIZE`. -* Useful tracking unnecessary mruby object allocation. - -`MRB_GC_ARENA_SIZE` -* Default value is `100`. -* Ignored when `MRB_GC_FIXED_ARENA` isn't defined. -* Defines fixed GC arena size. - -`MRB_HEAP_PAGE_SIZE` -* Defines value is `1024`. -* Specifies number of `RBasic` per each heap page. - -## Memory pool configuration. - -`POOL_ALIGNMENT` -* Default value is `4`. -* If you're allocating data types that requires alignment more than default value define the -largest value of required alignment. - -`POOL_PAGE_SIZE` -* Default value is `16000`. -* Specifies page size of pool page. -* Smaller the value is increases memory overhead. - -## State atexit configuration. - -`MRB_FIXED_STATE_ATEXIT_STACK` -* If defined enables fixed size `mrb_state` atexit stack. -* Raises `RuntimeError` when `mrb_state_atexit` call count to same `mrb_state` exceeds -`MRB_FIXED_STATE_ATEXIT_STACK_SIZE`'s value. - -`MRB_FIXED_STATE_ATEXIT_STACK_SIZE` -* Default value is `5`. -* If `MRB_FIXED_STATE_ATEXIT_STACK` isn't defined this macro is ignored. - -## `mrb_value` configuration. - -`MRB_ENDIAN_BIG` -* If defined compiles mruby for big endian machines. -* Used in `MRB_NAN_BOXING`. -* Some mrbgem use this mrbconf. - -`MRB_NAN_BOXING` -* If defined represent `mrb_value` in boxed `double`. -* Conflicts with `MRB_USE_FLOAT`. - -`MRB_WORD_BOXING` -* If defined represent `mrb_value` as a word. -* If defined `Float` will be a mruby object with `RBasic`. - -## Instance variable configuration. -`MRB_IV_SEGMENT_SIZE` -* Default value is `4`. -* Specifies size of each segment in segment list. - -## Other configuration. -`MRB_UTF8_STRING` -* Adds UTF-8 encoding support to character-oriented String instance methods. -* If it isn't defined, they only support the US-ASCII encoding. - -`MRB_FUNCALL_ARGC_MAX` -* Default value is `16`. -* Specifies 4th argument(`argc`) max value of `mrb_funcall`. -* Raises `ArgumentError` when the `argc` argument is bigger then this value `mrb_funcall`. - -`KHASH_DEFAULT_SIZE` -* Default value is `32`. -* Specifies default size of khash table bucket. -* Used in `kh_init_ ## name` function. - -`MRB_STR_BUF_MIN_SIZE` -* Default value is `128`. -* Specifies initial capacity of `RString` created by `mrb_str_buf_new` function.. diff --git a/web/server/h2o/libh2o/deps/mruby/doc/guides/mrbgems.md b/web/server/h2o/libh2o/deps/mruby/doc/guides/mrbgems.md deleted file mode 100644 index 258f405b5..000000000 --- a/web/server/h2o/libh2o/deps/mruby/doc/guides/mrbgems.md +++ /dev/null @@ -1,340 +0,0 @@ -# mrbgems - -mrbgems is a library manager to integrate C and Ruby extension in an easy and -standardised way into mruby. - -## Usage - -By default mrbgems is currently deactivated. As soon as you add a GEM to your -build configuration (i.e. *build_config.rb*), mrbgems will be activated and the -extension integrated. - -To add a GEM into the *build_config.rb* add the following line for example: -```ruby -conf.gem '/path/to/your/gem/dir' -``` - -You can also use a relative path which would be relative from the mruby root: -```ruby -conf.gem 'examples/mrbgems/ruby_extension_example' -``` - -A remote GIT repository location for a GEM is also supported: -```ruby -conf.gem :git => 'https://github.com/masuidrive/mrbgems-example.git', :branch => 'master' -conf.gem :github => 'masuidrive/mrbgems-example', :branch => 'master' -conf.gem :bitbucket => 'mruby/mrbgems-example', :branch => 'master' -``` - -To use mrbgem from [mgem-list](https://github.com/mruby/mgem-list) use `:mgem` option: -```ruby -conf.gem :mgem => 'mruby-yaml' -conf.gem :mgem => 'yaml' # 'mruby-' prefix could be omitted -``` - -If there is missing dependencies, mrbgem dependencies solver will reference -mrbgem from core or mgem-list. - -To pull all gems from remote GIT repository on build, call ```./minirake -p```, -or ```./minirake --pull-gems```. - -NOTE: `:bitbucket` option supports only git. Hg is unsupported in this version. - -## GemBox - -There are instances when you wish to add a collection of mrbgems into mruby at -once, or be able to substitute mrbgems based on configuration, without having to -add each gem to the *build_config.rb* file. A packaged collection of mrbgems -is called a GemBox. A GemBox is a file that contains a list of mrbgems to load -into mruby, in the same format as if you were adding them to *build_config.rb* -via `config.gem`, but wrapped in an `MRuby::GemBox` object. GemBoxes are -loaded into mruby via `config.gembox 'boxname'`. - -Below we have created a GemBox containing *mruby-time* and *mrbgems-example*: -```ruby -MRuby::GemBox.new do |conf| - conf.gem "#{root}/mrbgems/mruby-time" - conf.gem :github => 'masuidrive/mrbgems-example' -end -``` - -As mentioned, the GemBox uses the same conventions as `MRuby::Build`. The GemBox -must be saved with a *.gembox* extension inside the *mrbgems* directory to to be -picked up by mruby. - -To use this example GemBox, we save it as `custom.gembox` inside the *mrbgems* -directory in mruby, and add the following to our *build_config.rb* file inside -the build block: -```ruby -conf.gembox 'custom' -``` -This will cause the *custom* GemBox to be read in during the build process, -adding *mruby-time* and *mrbgems-example* to the build. - -If you want, you can put GemBox outside of mruby directory. In that case you must -specify an absolute path like below. -```ruby -conf.gembox "#{ENV["HOME"]}/mygemboxes/custom" -``` - -There are two GemBoxes that ship with mruby: [default](../../mrbgems/default.gembox) -and [full-core](../../mrbgems/full-core.gembox). The [default](../../mrbgems/default.gembox) GemBox -contains several core components of mruby, and [full-core](../../mrbgems/full-core.gembox) -contains every gem found in the *mrbgems* directory. - -## GEM Structure - -The maximal GEM structure looks like this: - - +- GEM_NAME <- Name of GEM - | - +- include/ <- Header for Ruby extension (will exported) - | - +- mrblib/ <- Source for Ruby extension - | - +- src/ <- Source for C extension - | - +- test/ <- Test code (Ruby) - | - +- mrbgem.rake <- GEM Specification - | - +- README.md <- Readme for GEM - -The folder *mrblib* contains pure Ruby files to extend mruby. The folder *src* -contains C/C++ files to extend mruby. The folder *include* contains C/C++ header -files. The folder *test* contains C/C++ and pure Ruby files for testing purposes -which will be used by `mrbtest`. *mrbgem.rake* contains the specification -to compile C and Ruby files. *README.md* is a short description of your GEM. - -## Build process - -mrbgems expects a specification file called *mrbgem.rake* inside of your -GEM directory. A typical GEM specification could look like this for example: -```ruby -MRuby::Gem::Specification.new('c_and_ruby_extension_example') do |spec| - spec.license = 'MIT' - spec.author = 'mruby developers' - spec.summary = 'Example mrbgem using C and ruby' -end -``` - -The mrbgems build process will use this specification to compile Object and Ruby -files. The compilation results will be added to *lib/libmruby.a*. This file exposes -the GEM functionality to tools like `mruby` and `mirb`. - -The following properties can be set inside of your `MRuby::Gem::Specification` for -information purpose: - -* `spec.license` or `spec.licenses` (A single license or a list of them under which this GEM is licensed) -* `spec.author` or `spec.authors` (Developer name or a list of them) -* `spec.version` (Current version) -* `spec.description` (Detailed description) -* `spec.summary` - * One line short description of mrbgem. - * Printed in build summary of rake when set. -* `spec.homepage` (Homepage) -* `spec.requirements` (External requirements as information for user) - -The `license` and `author` properties are required in every GEM! - -In case your GEM is depending on other GEMs please use -`spec.add_dependency(gem, *requirements[, default_get_info])` like: -```ruby -MRuby::Gem::Specification.new('c_and_ruby_extension_example') do |spec| - spec.license = 'MIT' - spec.author = 'mruby developers' - - # Add GEM dependency mruby-parser. - # The version must be between 1.0.0 and 1.5.2 . - spec.add_dependency('mruby-parser', '>= 1.0.0', '<= 1.5.2') - - # Use any version of mruby-uv from github. - spec.add_dependency('mruby-uv', '>= 0.0.0', :github => 'mattn/mruby-uv') - - # Use latest mruby-onig-regexp from github. (version requirements can be omitted) - spec.add_dependency('mruby-onig-regexp', :github => 'mattn/mruby-onig-regexp') - - # You can add extra mgems active only on test - spec.add_test_dependency('mruby-process', :github => 'iij/mruby-process') -end -``` - -The version requirements and default gem information are optional. - -Version requirement supports following operators: -* '=': is equal -* '!=': is not equal -* '>': is greater -* '<': is lesser -* '>=': is equal or greater -* '<=': is equal or lesser -* '~>': is equal or greater and is lesser than the next major version - * example 1: '~> 2.2.2' means '>= 2.2.2' and '< 2.3.0' - * example 2: '~> 2.2' means '>= 2.2.0' and '< 3.0.0' - -When more than one version requirements is passed, the dependency must satisfy all of it. - -You can have default gem to use as depedency when it's not defined in *build_config.rb*. -When the last argument of `add_dependency` call is `Hash`, it will be treated as default gem information. -Its format is same as argument of method `MRuby::Build#gem`, expect that it can't be treated as path gem location. - -When a special version of depedency is required, -use `MRuby::Build#gem` in *build_config.rb* to override default gem. - -If you have conflicting GEMs use the following method: -* `spec.add_conflict(gem, *requirements)` - * The `requirements` argument is same as in `add_dependency` method. - -like following code: -```ruby -MRuby::Gem::Specification.new 'some-regexp-binding' do |spec| - spec.license = 'BSD' - spec.author = 'John Doe' - - spec.add_conflict 'mruby-onig-regexp', '> 0.0.0' - spec.add_conflict 'mruby-hs-regexp' - spec.add_conflict 'mruby-pcre-regexp' - spec.add_conflict 'mruby-regexp-pcre' -end -``` - -In case your GEM has more complex build requirements you can use -the following options additionally inside of your GEM specification: - -* `spec.cc.flags` (C compiler flags) -* `spec.cc.defines` (C compiler defines) -* `spec.cc.include_paths` (C compiler include paths) -* `spec.linker.flags` (Linker flags) -* `spec.linker.libraries` (Linker libraries) -* `spec.linker.library_paths` (Linker additional library path) -* `spec.bins` (Generate binary file) -* `spec.rbfiles` (Ruby files to compile) -* `spec.objs` (Object files to compile) -* `spec.test_rbfiles` (Ruby test files for integration into mrbtest) -* `spec.test_objs` (Object test files for integration into mrbtest) -* `spec.test_preload` (Initialization files for mrbtest) - -You also can use `spec.mruby.cc` and `spec.mruby.linker` to add extra global parameters for compiler and linker. - -### include_paths and dependency - -Your GEM can export include paths to another GEMs that depends on your GEM. -By default, `/...absolute path.../{GEM_NAME}/include` will be exported. -So it is recommended not to put GEM's local header files on include/. - -These exports are retroactive. -For example: when B depends to C and A depends to B, A will get include paths exported by C. - -Exported include_paths are automatically appended to GEM local include_paths by Minirake. -You can use `spec.export_include_paths` accessor if you want more complex build. - - -## C Extension - -mruby can be extended with C. This is possible by using the C API to -integrate C libraries into mruby. - -### Preconditions - -mrbgems expects that you have implemented a C method called -`mrb_YOURGEMNAME_gem_init(mrb_state)`. `YOURGEMNAME` will be replaced -by the name of your GEM. If you call your GEM *c_extension_example*, your -initialisation method could look like this: -```C -void -mrb_c_extension_example_gem_init(mrb_state* mrb) { - struct RClass *class_cextension = mrb_define_module(mrb, "CExtension"); - mrb_define_class_method(mrb, class_cextension, "c_method", mrb_c_method, MRB_ARGS_NONE()); -} -``` - -### Finalize - -mrbgems expects that you have implemented a C method called -`mrb_YOURGEMNAME_gem_final(mrb_state)`. `YOURGEMNAME` will be replaced -by the name of your GEM. If you call your GEM *c_extension_example*, your -finalizer method could look like this: - -```C -void -mrb_c_extension_example_gem_final(mrb_state* mrb) { - free(someone); -} -``` - -### Example - - +- c_extension_example/ - | - +- src/ - | | - | +- example.c <- C extension source - | - +- test/ - | | - | +- example.rb <- Test code for C extension - | - +- mrbgem.rake <- GEM specification - | - +- README.md - -## Ruby Extension - -mruby can be extended with pure Ruby. It is possible to override existing -classes or add new ones in this way. Put all Ruby files into the *mrblib* -folder. - - -### Pre-Conditions - -none - -### Example - - +- ruby_extension_example/ - | - +- mrblib/ - | | - | +- example.rb <- Ruby extension source - | - +- test/ - | | - | +- example.rb <- Test code for Ruby extension - | - +- mrbgem.rake <- GEM specification - | - +- README.md - -## C and Ruby Extension - -mruby can be extended with C and Ruby at the same time. It is possible to -override existing classes or add new ones in this way. Put all Ruby files -into the *mrblib* folder and all C files into the *src* folder. - -mruby codes under *mrblib* directory would be executed after gem init C -function is called. Make sure *mruby script* depends on *C code* and -*C code* doesn't depend on *mruby script*. - -### Pre-Conditions - -See C and Ruby example. - -### Example - - +- c_and_ruby_extension_example/ - | - +- mrblib/ - | | - | +- example.rb <- Ruby extension source - | - +- src/ - | | - | +- example.c <- C extension source - | - +- test/ - | | - | +- example.rb <- Test code for C and Ruby extension - | - +- mrbgem.rake <- GEM specification - | - +- README.md diff --git a/web/server/h2o/libh2o/deps/mruby/doc/limitations.md b/web/server/h2o/libh2o/deps/mruby/doc/limitations.md deleted file mode 100644 index db8db9a5c..000000000 --- a/web/server/h2o/libh2o/deps/mruby/doc/limitations.md +++ /dev/null @@ -1,208 +0,0 @@ -# Limitations and Differences - -The philosophy of mruby is to be a lightweight implementation of -the Ruby ISO standard. These two objectives are partially contradicting. -Ruby is an expressive language with complex implementation details which -are difficult to implement in a lightweight manner. To cope with this, -limitations to the "Ruby Compatibility" are defined. - -This document is collecting these limitations. - -## Integrity - -This document does not contain a complete list of limitations. -Please help to improve it by submitting your findings. - - -## ```1/2``` gives ```0.5``` - -Since mruby does not have ```Bignum```, bigger integers are represented -by ```Float``` numbers. To enhance interoperability between ```Fixnum``` -and ```Float```, mruby provides ```Float#upto``` and other iterating -methods for the ```Float``` class. As a side effect, ```1/2``` gives ```0.5``` -not ```0```. - -## ```Array``` passed to ```puts``` - -Passing an Array to ```puts``` results in different output. - -```ruby -puts [1,2,3] -``` - -#### Ruby [ruby 2.0.0p645 (2015-04-13 revision 50299)] - -``` -1 -2 -3 -``` - -#### mruby [1.3.0 (2017-7-4)] - -``` -[1, 2, 3] -``` - -## ```Kernel.raise``` in rescue clause - -```Kernel.raise``` without arguments does not raise the current exception within -a rescue clause. - -```ruby -begin - 1 / 0 -rescue - raise -end -``` - -#### Ruby [ruby 2.0.0p645 (2015-04-13 revision 50299)] - -```ZeroDivisionError``` is raised. - -#### mruby [1.3.0 (2017-7-4)] - -No exception is raised. - -## Check of infinite recursion - -mruby does not check infinite recursion across C extensions. - -```ruby -def test; eval 'test'; end; test -``` - -#### Ruby [ruby 2.0.0p645 (2015-04-13 revision 50299)] - -```SystemStackError``` is raised. - -#### mruby [1.3.0 (2017-7-4)] - -Segmentation fault. - -## Fiber execution can't cross C function boundary - -mruby's ```Fiber``` is implemented in a similar way to Lua's co-routine. This -results in the consequence that you can't switch context within C functions. -Only exception is ```mrb_fiber_yield``` at return. - -## ```Array``` does not support instance variables - -To reduce memory consumption ```Array``` does not support instance variables. - -```ruby -class Liste < Array - def initialize(str = nil) - @feld = str - end -end - -p Liste.new "foobar" -``` - -#### Ruby [ruby 2.0.0p645 (2015-04-13 revision 50299)] - -``` [] ``` - -#### mruby [1.3.0 (2017-7-4)] - -```ArgumentError``` is raised. - -## Method visibility - -For simplicity reasons no method visibility (public/private/protected) is -supported. - -```ruby -class VisibleTest - - def public_method; end - - private - def private_method; end - -end - -p VisibleTest.new.respond_to?(:private_method, false) -p VisibleTest.new.respond_to?(:private_method, true) -``` - -#### Ruby [ruby 2.0.0p645 (2015-04-13 revision 50299)] - -``` -false -true -``` - -#### mruby [1.3.0 (2017-7-4)] - -``` -true -true -``` - -## defined? - -The ```defined?``` keyword is considered too complex to be fully -implemented. It is recommended to use ```const_defined?``` and -other reflection methods instead. - -```ruby -defined?(Foo) -``` - -#### Ruby [ruby 2.0.0p645 (2015-04-13 revision 50299)] - -``` -nil -``` - -#### mruby [1.3.0 (2017-7-4)] - -```NameError``` is raised. - -## ```alias``` on global variables - -Aliasing a global variable works in CRuby but is not part -of the ISO standard. - -```ruby -alias $a $__a__ -``` - -#### Ruby [ruby 2.0.0p645 (2015-04-13 revision 50299)] - -``` nil ``` - -#### mruby [1.3.0 (2017-7-4)] - -Syntax error - -## Operator modification - -An operator can't be overwritten by the user. - -```ruby -class String - def + - end -end - -'a' + 'b' -``` - -#### Ruby [ruby 2.0.0p645 (2015-04-13 revision 50299)] - -```ArgumentError``` is raised. -The re-defined ```+``` operator does not accept any arguments. - -#### mruby [1.3.0 (2017-7-4)] - -``` 'ab' ``` -Behavior of the operator wasn't changed. - -## ```Kernel.binding``` missing - -```Kernel.binding``` is not implemented as it is not in the -ISO standard. |