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Language/OS - Multiplatform Resource Library
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LANGUAGE OS.iso
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tcl
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tcl67.lha
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tcl6.7
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library
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init.tcl
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1992-10-22
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# init.tcl --
#
# Default system startup file for Tcl-based applications. Defines
# "unknown" procedure and auto-load facilities.
#
# $Header: /user6/ouster/tcl/scripts/RCS/init.tcl,v 1.12 92/10/22 12:04:50 ouster Exp $ SPRITE (Berkeley)
#
# Copyright 1991-1992 Regents of the University of California
# Permission to use, copy, modify, and distribute this
# software and its documentation for any purpose and without
# fee is hereby granted, provided that this copyright
# notice appears in all copies. The University of California
# makes no representations about the suitability of this
# software for any purpose. It is provided "as is" without
# express or implied warranty.
#
# unknown:
# Invoked when a Tcl command is invoked that doesn't exist in the
# interpreter:
#
# 1. See if the autoload facility can locate the command in a
# Tcl script file. If so, load it and execute it.
# 2. See if the command exists as an executable UNIX program.
# If so, "exec" the command.
# 3. If the command was invoked at top-level:
# (a) see if the command requests csh-like history substitution
# in one of the common forms !!, !<number>, or ^old^new. If
# so, emulate csh's history substitution.
# (b) see if the command is a unique abbreviation for another
# command. If so, invoke the command.
proc unknown args {
global auto_noexec auto_noload env unknown_pending;
set name [lindex $args 0]
if ![info exists auto_noload] {
#
# Make sure we're not trying to load the same proc twice.
#
if [info exists unknown_pending($name)] {
unset unknown_pending($name)
if ![array size unknown_pending] {
unset unknown_pending
}
error "self-referential recursion in \"unknown\" for command \"$name\"";
}
set unknown_pending($name) pending;
set ret [auto_load $name];
unset unknown_pending($name);
if ![array size unknown_pending] {
unset unknown_pending
}
if $ret {
return [uplevel $args]
}
}
if ![info exists auto_noexec] {
if [auto_execok $name] {
return [uplevel exec $args]
}
}
if {([info level] == 1) && ([info script] == "")} {
if {$name == "!!"} {
return [uplevel {history redo}]
}
if [regexp {^!(.+)$} $name dummy event] {
return [uplevel history redo $event]
}
if [regexp {^\^(.*)\^(.*)^?$} $name dummy old new] {
return [uplevel history substitute $old $new]
}
set cmds [info commands $name*]
if {[llength $cmds] == 1} {
return [uplevel [lreplace $args 0 0 $cmds]]
}
if {[llength $cmds] != 0} {
if {$name == ""} {
error "empty command name \"\""
} else {
error "ambiguous command name \"$name\": [lsort $cmds]"
}
}
}
error "invalid command name \"$name\""
}
# auto_load:
# Checks a collection of library directories to see if a procedure
# is defined in one of them. If so, it sources the appropriate
# library file to create the procedure. Returns 1 if it successfully
# loaded the procedure, 0 otherwise.
proc auto_load cmd {
global auto_index auto_oldpath auto_path env
if [info exists auto_index($cmd)] {
uplevel #0 source $auto_index($cmd)
return 1
}
if [catch {set path $auto_path}] {
if [catch {set path $env(TCLLIBPATH)}] {
if [catch {set path [info library]}] {
return 0
}
}
}
if [info exists auto_oldpath] {
if {$auto_oldpath == $path} {
return 0
}
}
set auto_oldpath $path
catch {unset auto_index}
foreach dir $path {
set f ""
catch {
set f [open $dir/tclIndex]
if {[gets $f] != "# Tcl autoload index file: each line identifies a Tcl"} {
puts stdout "Bad id line in file $dir/tclIndex"
error done
}
while {[gets $f line] >= 0} {
if {([string index $line 0] == "#") || ([llength $line] != 2)} {
continue
}
set name [lindex $line 0]
if {![info exists auto_index($name)]} {
set auto_index($name) $dir/[lindex $line 1]
}
}
}
if {$f != ""} {
close $f
}
}
if [info exists auto_index($cmd)] {
uplevel #0 source $auto_index($cmd)
return 1
}
return 0
}
# auto_execok:
# Returns 1 if there's an executable in the current path for the
# given name, 0 otherwise. Builds an associative array auto_execs
# that caches information about previous checks, for speed.
proc auto_execok name {
global auto_execs env
if [info exists auto_execs($name)] {
return $auto_execs($name)
}
set auto_execs($name) 0
foreach dir [split $env(PATH) :] {
if {[file executable $dir/$name] && ![file isdirectory $dir/$name]} {
set auto_execs($name) 1
return 1
}
}
return 0
}
# auto_reset:
# Destroy all cached information for auto-loading and auto-execution,
# so that the information gets recomputed the next time it's needed.
# Also delete any procedures that are listed in the auto-load index
# except those related to auto-loading.
proc auto_reset {} {
global auto_execs auto_index auto_oldpath
foreach p [info procs] {
if {[info exists auto_index($p)] && ($p != "unknown")
&& ![string match auto_* $p]} {
rename $p {}
}
}
catch {unset auto_execs}
catch {unset auto_index}
catch {unset auto_oldpath}
}
# auto_mkindex:
# Regenerate a tclIndex file from Tcl source files. Takes two arguments:
# the name of the directory in which the tclIndex file is to be placed,
# and a glob pattern to use in that directory to locate all of the relevant
# files.
proc auto_mkindex {dir files} {
global errorCode errorInfo
set oldDir [pwd]
cd $dir
set dir [pwd]
append index "# Tcl autoload index file: each line identifies a Tcl\n"
append index "# procedure and the file where that procedure is\n"
append index "# defined. Generated by the \"auto_mkindex\" command.\n"
append index "\n"
foreach file [glob $files] {
set f ""
set error [catch {
set f [open $file]
while {[gets $f line] >= 0} {
if [regexp {^proc[ ]+([^ ]*)} $line match procName] {
append index "[list $procName $file]\n"
}
}
close $f
} msg]
if $error {
set code $errorCode
set info $errorInfo
catch [close $f]
cd $oldDir
error $msg $info $code
}
}
set f [open tclIndex w]
puts $f $index nonewline
close $f
cd $oldDir
}