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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 06:17:24 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 06:17:24 +0000
commit9d8085074991d5c0a42d6fc96a2d1a3ee918aad1 (patch)
treec85bca1e6c11eb872edfc64c524d20f2b7e3307b /examples/functions/autoload
parentInitial commit. (diff)
downloadbash-70baf9b08adef67074da9e233fa847220a474b78.tar.xz
bash-70baf9b08adef67074da9e233fa847220a474b78.zip
Adding upstream version 5.1.upstream/5.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+#
+# An almost ksh-compatible `autoload'. A function declared as `autoload' will
+# be read in from a file the same name as the function found by searching the
+# $FPATH (which works the same as $PATH), then that definition will be run.
+#
+# To do this without source support, we define a dummy function that, when
+# executed, will load the file (thereby re-defining the function), then
+# execute that newly-redefined function with the original arguments.
+#
+# It's not identical to ksh because ksh apparently does lazy evaluation
+# and looks for the file to load from only when the function is referenced.
+# This one requires that the file exist when the function is declared as
+# `autoload'.
+#
+# usage: autoload func [func...]
+#
+# The first cut of this was by Bill Trost, trost@reed.bitnet
+#
+# Chet Ramey
+# chet@ins.CWRU.Edu
+
+#
+# Declare a function ($1) to be autoloaded from a file ($2) when it is first
+# called. This defines a `temporary' function that will `.' the file
+# containing the real function definition, then execute that new definition with
+# the arguments given to this `fake' function. The autoload function defined
+# by the file and the file itself *must* be named identically.
+#
+
+aload()
+{
+ eval $1 '() { . '$2' ; '$1' "$@" ; return $? ; }'
+}
+
+#
+# Search $FPATH for a file the same name as the function given as $1, and
+# autoload the function from that file. There is no default $FPATH.
+#
+
+autoload()
+{
+ #
+ # Save the list of functions; we're going to blow away the arguments
+ # in a second. If any of the names contain white space, TFB.
+ #
+
+ local args="$*"
+
+ #
+ # This should, I think, list the functions marked as autoload and not
+ # yet defined, but we don't have enough information to do that here.
+ #
+ if [ $# -eq 0 ] ; then
+ echo "usage: autoload function [function...]" >&2
+ return 1
+ fi
+
+ #
+ # If there is no $FPATH, there is no work to be done
+ #
+
+ if [ -z "$FPATH" ] ; then
+ echo autoload: FPATH not set or null >&2
+ return 1
+ fi
+
+ #
+ # This treats FPATH exactly like PATH: a null field anywhere in the
+ # FPATH is treated the same as the current directory.
+ #
+ # The path splitting command is taken from Kernighan and Pike
+ #
+
+# fp=$(echo $FPATH | sed 's/^:/.:/
+# s/::/:.:/g
+# s/:$/:./
+# s/:/ /g')
+
+ # replaced with builtin mechanisms 2001 Oct 10
+
+ fp=${FPATH/#:/.:}
+ fp=${fp//::/:.:}
+ fp=${fp/%:/:.}
+ fp=${fp//:/ }
+
+ for FUNC in $args ; do
+ #
+ # We're blowing away the arguments to autoload here...
+ # We have to; there are no arrays (well, there are, but
+ # this doesn't use them yet).
+ #
+ set -- $fp
+
+ while [ $# -ne 0 ] ; do
+ if [ -f $1/$FUNC ] ; then
+ break # found it!
+ fi
+ shift
+ done
+
+ if [ $# -eq 0 ] ; then
+ echo "$FUNC: autoload function not found" >&2
+ continue
+ fi
+
+# echo auto-loading $FUNC from $1/$FUNC
+ aload $FUNC $1/$FUNC
+ done
+
+ return 0
+}