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| -rw-r--r-- | examples/functions/autoload.v2 | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/examples/functions/autoload.v2 b/examples/functions/autoload.v2 new file mode 100644 index 0000000..e29c695 --- /dev/null +++ b/examples/functions/autoload.v2 @@ -0,0 +1,192 @@ +# +# 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 [-pu] [func ...] +# +# options: +# -p print in a format that can be reused as input +# -u unset each function and remove it from the autoload list +# +# The first cut of this was by Bill Trost, trost@reed.edu +# +# Chet Ramey +# chet@ins.CWRU.Edu + +unset _AUTOLOADS +_aindex=0 + +# +# 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 $? ; }' + _autoload_addlist "$1" +} + +_autoload_addlist() +{ + local i=0 + + while (( i < $_aindex )); do + case "${_AUTOLOADS[i]}" in + "$1") return 1 ;; + esac + (( i += 1 )) + done + _AUTOLOADS[_aindex]="$1" + (( _aindex += 1 )) + return 0 +} + +_autoload_dump() +{ + local func + + for func in ${_AUTOLOADS[@]}; do + [ -n "$1" ] && echo -n "autoload " + echo "$func" + done +} + +# Remove $1 from the list of autoloaded functions +_autoload_remove_one() +{ + local i=0 nnl=0 + local -a nlist + + while (( i < _aindex )); do + case "${_AUTOLOADS[i]}" in + "$1") ;; + *) nlist[nnl]="${_AUTOLOADS[i]}" ; (( nnl += 1 ));; + esac + (( i += 1 )) + done + unset _AUTOLOADS _aindex + eval _AUTOLOADS=( ${nlist[@]} ) + _aindex=$nnl +} + +# Remove all function arguments from the list of autoloaded functions +_autoload_remove() +{ + local func i es=0 + + # first unset the autoloaded functions + for func; do + i=0 + while (( i < _aindex )); do + case "${_AUTOLOADS[i]}" in + "$func") unset -f $func ; break ;; + esac + (( i += 1 )) + done + if (( i == _aindex )); then + echo "autoload: $func: not an autoloaded function" >&2 + es=1 + fi + done + + # then rebuild the list of autoloaded functions + for func ; do + _autoload_remove_one "$func" + done + + return $es +} + +# +# 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() +{ + local -a fp + local _autoload_unset nfp i + + if (( $# == 0 )) ; then + _autoload_dump + return 0 + fi + + OPTIND=1 + while getopts pu opt + do + case "$opt" in + p) _autoload_dump printable; return 0;; + u) _autoload_unset=y ;; + *) echo "autoload: usage: autoload [-pu] [function ...]" >&2 + return 1 ;; + esac + done + + shift $(( $OPTIND - 1 )) + + if [ -n "$_autoload_unset" ]; then + _autoload_remove "$@" + return $? + 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. + # + # This turns $FPATH into an array, substituting `.' for `' + # + eval fp=( $( + IFS=':' + set -- ${FPATH} + for p in "$@" ; do echo -n "${p:-.} "; done + ) + ) + + nfp=${#fp[@]} + + for FUNC ; do + i=0; + while (( i < nfp )) ; do + if [ -f ${fp[i]}/$FUNC ] ; then + break # found it! + fi + (( i += 1 )) + done + + if (( i == nfp )) ; then + echo "autoload: $FUNC: autoload function not found" >&2 + es=1 + continue + fi + +# echo auto-loading $FUNC from ${fp[i]}/$FUNC + _aload $FUNC ${fp[i]}/$FUNC + es=0 + done + + return $es +} |