runtime/tcl/tix8.4.3/Event.tcl

# -*- mode: TCL; fill-column: 75; tab-width: 8; coding: iso-latin-1-unix -*-
#
#	$Id: Event.tcl,v 1.6 2004/04/09 21:37:01 hobbs Exp $
#
# Event.tcl --
#
#	Handles the event bindings of the -command and -browsecmd options
#	(and various of others such as -validatecmd).
#
# Copyright (c) 1993-1999 Ioi Kim Lam.
# Copyright (c) 2000-2001 Tix Project Group.
# Copyright (c) 2004 ActiveState
#
# See the file "license.terms" for information on usage and redistribution
# of this file, and for a DISCLAIMER OF ALL WARRANTIES.
#

#----------------------------------------------------------------------
# Evaluate high-level bindings (-command, -browsecmd, etc):
# with % subsitution or without (compatibility mode)
#
#
# BUG : if a -command is intercepted by a hook, the hook must use
#       the same record name as the issuer of the -command. For the time
#	being, you must use the name "bind" as the record name!!!!!
#
#----------------------------------------------------------------------

namespace eval ::tix {
    variable event_flags ""
    set evs [list % \# a b c d f h k m o p s t w x y A B E K N R S T W X Y]
    foreach ev $evs {
	lappend event_flags "%$ev"
    }

    # This is a "name stack" for storing the "bind" structures
    #
    # The bottom of the event stack is usually a raw event (generated by
    # tixBind) but it may also be a programatically triggered (caused by
    # tixEvalCmdBinding)
    variable EVENT
    set EVENT(nameStack)	""
    set EVENT(stackLevel)	0
}

proc tixBind {tag event action} {
    set cmd [linsert $::tix::event_flags 0 _tixRecordFlags $event]
    append cmd "; $action; _tixDeleteFlags;"

    bind $tag $event $cmd
}

proc tixPushEventStack {} {
    variable ::tix::EVENT

    set lastEvent [lindex $EVENT(nameStack) 0]
    incr EVENT(stackLevel)
    set thisEvent ::tix::_event$EVENT(stackLevel)

    set EVENT(nameStack) [list $thisEvent $EVENT(nameStack)]

    if {$lastEvent == ""} {
	upvar #0 $thisEvent this
	set this(type) <Application>
    } else {
	upvar #0 $lastEvent last
	upvar #0 $thisEvent this

	foreach name [array names last] {
	    set this($name) $last($name)
	}
    }

    return $thisEvent
}

proc tixPopEventStack {varName} {
    variable ::tix::EVENT

    if {$varName ne [lindex $EVENT(nameStack) 0]} {
	error "unmatched tixPushEventStack and tixPopEventStack calls"
    }
    incr EVENT(stackLevel) -1
    set EVENT(nameStack) [lindex $EVENT(nameStack) 1]
    global $varName
    unset $varName
}


# Events triggered by tixBind
#
proc _tixRecordFlags [concat event $::tix::event_flags] {
    set thisName [tixPushEventStack]; upvar #0 $thisName this

    set this(type) $event
    foreach f $::tix::event_flags {
	set this($f) [set $f]
    }
}

proc _tixDeleteFlags {} {
    variable ::tix::EVENT

    tixPopEventStack [lindex $EVENT(nameStack) 0]
}

# programatically trigged events
#
proc tixEvalCmdBinding {w cmd {subst ""} args} {
    global tixPriv tix
    variable ::tix::EVENT

    set thisName [tixPushEventStack]; upvar #0 $thisName this

    if {$subst != ""} {
	upvar $subst bind

	if {[info exists bind(specs)]} {
	    foreach spec $bind(specs) {
		set this($spec) $bind($spec)
	    }
	}
	if {[info exists bind(type)]} {
	    set this(type) $bind(type)
	}
    }

    if {[catch {
	if {![info exists tix(-extracmdargs)]
	    || [string is true -strict $tix(-extracmdargs)]} {
	    # Compatibility mode
	    set ret [uplevel \#0 $cmd $args]
	} else {
	    set ret [uplevel 1 $cmd]
	}
    } error]} {
	if {[catch {tixCmdErrorHandler $error} error]} {
	    # double fault: just print out 
	    tixBuiltInCmdErrorHandler $error
	}
	tixPopEventStack $thisName
	return ""
    } else {
	tixPopEventStack $thisName

	return $ret
    }
}

proc tixEvent {option args} {
    global tixPriv
    variable ::tix::EVENT
    set varName [lindex $EVENT(nameStack) 0]

    if {$varName == ""} {
	error "tixEvent called when no event is being processed"
    } else {
	upvar #0 $varName event
    }

    switch -exact -- $option {
	type {
	    return $event(type)
	}
	value {
	    if {[info exists event(%V)]} {
		return $event(%V)
	    } else {
		return ""
	    }
	}
	flag {
	    set f %[lindex $args 0]
	    if {[info exists event($f)]} {
		return $event($f)
	    }
	    error "The flag \"[lindex $args 0]\" does not exist"
	}
	match {
	    return [string match [lindex $args 0] $event(type)]
	}
	default {
	    error "unknown option \"$option\""
	}
    }
}

# tixBuiltInCmdErrorHandler --
#
#	Default method to report command handler errors. This procedure is
#	also called if double-fault happens (command handler causes error,
#	then tixCmdErrorHandler causes error).
#
proc tixBuiltInCmdErrorHandler {errorMsg} {
    global errorInfo tcl_platform
    if {![info exists errorInfo]} {
	set errorInfo "???"
    }
    if {$tcl_platform(platform) eq "windows"} {
	bgerror "Tix Error: $errorMsg"
    } else {
	puts "Error:\n $errorMsg\n$errorInfo"
    }
}

# tixCmdErrorHandler --
#
#	You can redefine this command to handle the errors that occur
#	in the command handlers. See the programmer's documentation
#	for details
#
if {![llength [info commands tixCmdErrorHandler]]} {
    proc tixCmdErrorHandler {errorMsg} {
	tixBuiltInCmdErrorHandler $errorMsg
    }
}