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Tcl Evaluator-In-A-Page
Tcl Evaluator-in-a-Page
Below is a little evaluator for Tcl commands. Type any valid Tcl command
in and see the result immediately. Check out our quick tour of the
Tcl syntax . For example, to create a new
button, type the following:
button .b -text hello -background red
pack .b
When you're done with the button, type:
destroy .b
and it's gone. You may also want to use the puts
command to output results from within loops. For example:
foreach proc [info procs] {
puts "$proc [info args $proc]"
}
To learn more about Tcl, read either Brent
Welch's or John Ousterhout's
Tcl books. Many more Tcl and Tk resources are available here .
Source:
Here is the source for the evaluator application:
# A frame, scrollbar, and text
frame .eval
set _t [text .eval.t -width 40 -height 15 -yscrollcommand {.eval.s set}]
scrollbar .eval.s -command {.eval.t yview}
pack .eval.s -side left -fill y
pack .eval.t -side right -fill both -expand true
pack .eval -fill both -expand true
# Insert the prompt and initialize the limit mark
.eval.t insert insert "Tcl eval log\n"
set prompt "tcl> "
.eval.t insert insert $prompt
.eval.t mark set limit insert
.eval.t mark gravity limit left
focus .eval.t
# Keybindings that limit input and eval things
bind .eval.t { _Eval .eval.t ; break }
bind .eval.t {
if [%W compare insert < limit] {
%W mark set insert end
}
}
bindtags .eval.t {.eval.t Text all}
proc _Eval { t } {
global prompt
set command [$t get limit end]
if [info complete $command] {
$t insert insert \n
set err [catch {uplevel #0 $command} result]
if {[string length $result] > 0} {
$t insert insert $result\n
}
$t insert insert $prompt
$t see insert
$t mark set limit insert
return
} else {
$t insert insert \n
}
}
proc puts {args} {
if {[string match -nonewline* $args]} {
set args [lrange $args 1 end]
set nonewline 1
}
.eval.t insert end [lindex $args end] ;# Ignore file specifier
if ![info exists nonewline] {
.eval.t insert end \n
}
}