path: root/contrib/tcl/library/init.tcl

# init.tcl --
#
# Default system startup file for Tcl-based applications.  Defines
# "unknown" procedure and auto-load facilities.
#
# SCCS: @(#) init.tcl 1.54 96/04/21 13:55:08
#
# Copyright (c) 1991-1993 The Regents of the University of California.
# Copyright (c) 1994-1996 Sun Microsystems, Inc.
#
# See the file "license.terms" for information on usage and redistribution
# of this file, and for a DISCLAIMER OF ALL WARRANTIES.
#

if {[info commands package] == ""} {
    error "version mismatch: library\nscripts expect Tcl version 7.5b1 or later but the loaded version is\nonly [info patchlevel]"
}
package require -exact Tcl 7.5
if [catch {set auto_path $env(TCLLIBPATH)}] {
    set auto_path ""
}
if {[lsearch -exact $auto_path [info library]] < 0} {
    lappend auto_path [info library]
}
package unknown tclPkgUnknown
if {[info commands exec] == ""} {
    # Some machines, such as the Macintosh, do not have exec 
    set auto_noexec 1
}
set errorCode ""
set errorInfo ""

# unknown --
# This procedure is called when a Tcl command is invoked that doesn't
# exist in the interpreter.  It takes the following steps to make the
# command available:
#
#	1. See if the autoload facility can locate the command in a
#	   Tcl script file.  If so, load it and execute it.
#	2. If the command was invoked interactively at top-level:
#	    (a) see if the command exists as an executable UNIX program.
#		If so, "exec" the command.
#	    (b) 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.
#	    (c) see if the command is a unique abbreviation for another
#		command.  If so, invoke the command.
#
# Arguments:
# args -	A list whose elements are the words of the original
#		command, including the command name.

proc unknown args {
    global auto_noexec auto_noload env unknown_pending tcl_interactive
    global errorCode errorInfo

    # Save the values of errorCode and errorInfo variables, since they
    # may get modified if caught errors occur below.  The variables will
    # be restored just before re-executing the missing command.

    set savedErrorCode $errorCode
    set savedErrorInfo $errorInfo
    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($name)
	    if {[array size unknown_pending] == 0} {
		unset unknown_pending
	    }
	    return -code error "self-referential recursion in \"unknown\" for command \"$name\"";
	}
	set unknown_pending($name) pending;
	set ret [catch {auto_load $name} msg]
	unset unknown_pending($name);
	if {$ret != 0} {
	    return -code $ret -errorcode $errorCode \
		"error while autoloading \"$name\": $msg"
	}
	if ![array size unknown_pending] {
	    unset unknown_pending
	}
	if $msg {
	    set errorCode $savedErrorCode
	    set errorInfo $savedErrorInfo
	    set code [catch {uplevel $args} msg]
	    if {$code ==  1} {
		#
		# Strip the last five lines off the error stack (they're
		# from the "uplevel" command).
		#

		set new [split $errorInfo \n]
		set new [join [lrange $new 0 [expr [llength $new] - 6]] \n]
		return -code error -errorcode $errorCode \
			-errorinfo $new $msg
	    } else {
		return -code $code $msg
	    }
	}
    }
    if {([info level] == 1) && ([info script] == "") \
	    && [info exists tcl_interactive] && $tcl_interactive} {
	if ![info exists auto_noexec] {
	    if [auto_execok $name] {
		set errorCode $savedErrorCode
		set errorInfo $savedErrorInfo
		return [uplevel exec >&@stdout <@stdin $args]
	    }
	}
	set errorCode $savedErrorCode
	set errorInfo $savedErrorInfo
	if {$name == "!!"} {
	    return [uplevel {history redo}]
	}
	if [regexp {^!(.+)$} $name dummy event] {
	    return [uplevel [list history redo $event]]
	}
	if [regexp {^\^([^^]*)\^([^^]*)\^?$} $name dummy old new] {
	    return [uplevel [list 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 == ""} {
		return -code error "empty command name \"\""
	    } else {
		return -code error \
			"ambiguous command name \"$name\": [lsort $cmds]"
	    }
	}
    }
    return -code error "invalid command name \"$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.
#
# Arguments: 
# cmd -			Name of the command to find and load.

proc auto_load cmd {
    global auto_index auto_oldpath auto_path env errorInfo errorCode

    if [info exists auto_index($cmd)] {
	uplevel #0 $auto_index($cmd)
	return [expr {[info commands $cmd] != ""}]
    }
    if ![info exists auto_path] {
	return 0
    }
    if [info exists auto_oldpath] {
	if {$auto_oldpath == $auto_path} {
	    return 0
	}
    }
    set auto_oldpath $auto_path
    for {set i [expr [llength $auto_path] - 1]} {$i >= 0} {incr i -1} {
	set dir [lindex $auto_path $i]
	set f ""
	if [catch {set f [open [file join $dir tclIndex]]}] {
	    continue
	}
	set error [catch {
	    set id [gets $f]
	    if {$id == "# Tcl autoload index file, version 2.0"} {
		eval [read $f]
	    } elseif {$id == "# Tcl autoload index file: each line identifies a Tcl"} {
		while {[gets $f line] >= 0} {
		    if {([string index $line 0] == "#")
			    || ([llength $line] != 2)} {
			continue
		    }
		    set name [lindex $line 0]
		    set auto_index($name) \
			"source [file join $dir [lindex $line 1]]"
		}
	    } else {
		error "[file join $dir tclIndex] isn't a proper Tcl index file"
	    }
	} msg]
	if {$f != ""} {
	    close $f
	}
	if $error {
	    error $msg $errorInfo $errorCode
	}
    }
    if [info exists auto_index($cmd)] {
	uplevel #0 $auto_index($cmd)
	if {[info commands $cmd] != ""} {
	    return 1
	}
    }
    return 0
}

if {[string compare $tcl_platform(platform) windows] == 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.
#
# Arguments: 
# name -			Name of a command.

# Windows version.
#
# Note that info executable doesn't work under Windows, so we have to
# look for files with .exe, .com, or .bat extensions.  Also, the path
# may be in the Path or PATH environment variables, and path
# components are separated with semicolons, not colons as under Unix.
#
proc auto_execok name {
    global auto_execs env

    if [info exists auto_execs($name)] {
	return $auto_execs($name)
    }
    set auto_execs($name) 0
    if {[file pathtype $name] != "relative"} {
	foreach ext {.exe .bat .cmd} {
	    if {[file exists ${name}${ext}]
		&& ![file isdirectory ${name}${ext}]} {
		set auto_execs($name) 1
	    }
	}
	return $auto_execs($name)
    }
    if {! [info exists env(PATH)]} {
	if [info exists env(Path)] {
	    set path $env(Path)
	} else {
	    return 0
	}
    } else {
	set path $env(PATH)
    }
    foreach dir [split $path {;}] {
	if {$dir == ""} {
	    set dir .
	}
	foreach ext {.exe .bat .cmd} {
	    set file [file join $dir ${name}${ext}]
	    if {[file exists $file] && ![file isdirectory $file]} {
		set auto_execs($name) 1
		return 1
	    }
	}
    }
    return 0
}

} else {

# Unix version.
#
proc auto_execok name {
    global auto_execs env

    if [info exists auto_execs($name)] {
	return $auto_execs($name)
    }
    set auto_execs($name) 0
    if {[file pathtype $name] != "relative"} {
	if {[file executable $name] && ![file isdirectory $name]} {
	    set auto_execs($name) 1
	}
	return $auto_execs($name)
    }
    foreach dir [split $env(PATH) :] {
	if {$dir == ""} {
	    set dir .
	}
	set file [file join $dir $name]
	if {[file executable $file] && ![file isdirectory $file]} {
	    set auto_execs($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.
#
# Arguments: 
# None.

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 as argument
# the name of the directory in which the tclIndex file is to be placed,
# followed by any number of glob patterns to use in that directory to
# locate all of the relevant files.
#
# Arguments: 
# dir -			Name of the directory in which to create an index.
# args -		Any number of additional arguments giving the
#			names of files within dir.  If no additional
#			are given auto_mkindex will look for *.tcl.

proc auto_mkindex {dir args} {
    global errorCode errorInfo
    set oldDir [pwd]
    cd $dir
    set dir [pwd]
    append index "# Tcl autoload index file, version 2.0\n"
    append index "# This file is generated by the \"auto_mkindex\" command\n"
    append index "# and sourced to set up indexing information for one or\n"
    append index "# more commands.  Typically each line is a command that\n"
    append index "# sets an element in the auto_index array, where the\n"
    append index "# element name is the name of a command and the value is\n"
    append index "# a script that loads the command.\n\n"
    if {$args == ""} {
	set args *.tcl
    }
    foreach file [eval glob $args] {
	set f ""
	set error [catch {
	    set f [open $file]
	    while {[gets $f line] >= 0} {
		if [regexp {^proc[ 	]+([^ 	]*)} $line match procName] {
		    append index "set [list auto_index($procName)]"
		    append index " \[list source \[file join \$dir [list $file]\]\]\n"
		}
	    }
	    close $f
	} msg]
	if $error {
	    set code $errorCode
	    set info $errorInfo
	    catch {close $f}
	    cd $oldDir
	    error $msg $info $code
	}
    }
    set f ""
    set error [catch {
	set f [open tclIndex w]
	puts $f $index nonewline
	close $f
	cd $oldDir
    } msg]
    if $error {
	set code $errorCode
	set info $errorInfo
	catch {close $f}
	cd $oldDir
	error $msg $info $code
    }
}

# pkg_mkIndex --
# This procedure creates a package index in a given directory.  The
# package index consists of a "pkgIndex.tcl" file whose contents are
# a Tcl script that sets up package information with "package require"
# commands.  The commands describe all of the packages defined by the
# files given as arguments.
#
# Arguments:
# dir -			Name of the directory in which to create the index.
# args -		Any number of additional arguments, each giving
#			a glob pattern that matches the names of one or
#			more shared libraries or Tcl script files in
#			dir.

proc pkg_mkIndex {dir args} {
    global errorCode errorInfo
    append index "# Tcl package index file, version 1.0\n"
    append index "# This file is generated by the \"pkg_mkIndex\" command\n"
    append index "# and sourced either when an application starts up or\n"
    append index "# by a \"package unknown\" script.  It invokes the\n"
    append index "# \"package ifneeded\" command to set up package-related\n"
    append index "# information so that packages will be loaded automatically\n"
    append index "# in response to \"package require\" commands.  When this\n"
    append index "# script is sourced, the variable \$dir must contain the\n"
    append index "# full path name of this file's directory.\n"
    set oldDir [pwd]
    cd $dir
    foreach file [eval glob $args] {
	# For each file, figure out what commands and packages it provides.
	# To do this, create a child interpreter, load the file into the
	# interpreter, and get a list of the new commands and packages
	# that are defined.  Define an empty "package unknown" script so
	# that there are no recursive package inclusions.

	set c [interp create]
	$c eval [list set file $file]
	if [catch {
	    $c eval {
		proc dummy args {}
		package unknown dummy
		set origCmds [info commands]
		set dir ""		;# in case file is pkgIndex.tcl
		set pkgs ""

		# The "file join ." command below is necessary.  Without it,
		# if the file name has no \'s and we're on UNIX, the
		# LD_LIBRARY_PATH search mechanism will be invoked, which
		# could cause the wrong file to be used.

		if [catch {load [file join . $file]}] {
		    if [catch {source $file}] {
			puts $errorInfo
			error "can't either load or source $file"
		    } else {
			set type source
		    }
		} else {
		    set type load
		}
		foreach i [info commands] {
		    set cmds($i) 1
		}
		foreach i $origCmds {
		    catch {unset cmds($i)}
		}
		foreach i [package names] {
		    if {([string compare [package provide $i] ""] != 0)
			    && ([string compare $i Tcl] != 0)} {
			lappend pkgs [list $i [package provide $i]]
		    }
		}
	    }
	} msg] {
	    interp delete $c
	    error $msg $errorInfo $errorCode
	}
	foreach pkg [$c eval set pkgs] {
	    lappend files($pkg) [list $file [$c eval set type] \
		    [lsort [$c eval array names cmds]]]
	}
	interp delete $c
    }
    foreach pkg [lsort [array names files]] {
	append index "\npackage ifneeded $pkg\
		\"tclPkgSetup \$dir [lrange $pkg 0 0] [lrange $pkg 1 1]\
		[list $files($pkg)]\""
    }
    set f [open pkgIndex.tcl w]
    puts $f $index
    close $f
    cd $oldDir
}

# tclPkgSetup --
# This is a utility procedure use by pkgIndex.tcl files.  It is invoked
# as part of a "package ifneeded" script.  It calls "package provide"
# to indicate that a package is available, then sets entries in the
# auto_index array so that the package's files will be auto-loaded when
# the commands are used.
#
# Arguments:
# dir -			Directory containing all the files for this package.
# pkg -			Name of the package (no version number).
# version -		Version number for the package, such as 2.1.3.
# files -		List of files that constitute the package.  Each
#			element is a sub-list with three elements.  The first
#			is the name of a file relative to $dir, the second is
#			"load" or "source", indicating whether the file is a
#			loadable binary or a script to source, and the third
#			is a list of commands defined by this file.

proc tclPkgSetup {dir pkg version files} {
    global auto_index

    package provide $pkg $version
    foreach fileInfo $files {
	set f [lindex $fileInfo 0]
	set type [lindex $fileInfo 1]
	foreach cmd [lindex $fileInfo 2] {
	    if {$type == "load"} {
		set auto_index($cmd) [list load [file join $dir $f] $pkg]
	    } else {
		set auto_index($cmd) [list source [file join $dir $f]]
	    } 
	}
    }
}

# tclPkgUnknown --
# This procedure provides the default for the "package unknown" function.
# It is invoked when a package that's needed can't be found.  It scans
# the auto_path directories looking for pkgIndex.tcl files and sources any
# such files that are found to setup the package database.
#
# Arguments:
# name -		Name of desired package.  Not used.
# version -		Version of desired package.  Not used.
# exact -		Either "-exact" or omitted.  Not used.

proc tclPkgUnknown {name version {exact {}}} {
    global auto_path

    if ![info exists auto_path] {
	return
    }
    for {set i [expr [llength $auto_path] - 1]} {$i >= 0} {incr i -1} {
	set dir [lindex $auto_path $i]
	set file [file join $dir pkgIndex.tcl]
	if [file readable $file] {
	    source $file
	}
    }
}