#
# 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
# containg 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
}