Tcl/Tk is a simple way to script small GUIs.
Can anyone give a nice example with a button and a text widget. When the button is pressed should a shell command be executed and the output piped to the text widget.
If you have other nice and clean examples for useful tasks, please add them too.
Here's a more complete example using fileevents. This will auto-scroll all the time. For usability purposes you probably only want to auto-scroll if the bottom of the text is visible (ie: if the user hasn't moved the scrollbar) but I'll leave that as an exercise for the reader to keep this already long example from getting any longer.
package require Tk
proc main {} {
if {[lsearch -exact [font names] TkDefaultFont] == -1} {
# older versions of Tk don't define this font, so pick something
# suitable
font create TkDefaultFont -family Helvetica -size 12
}
# in 8.5 we can use {*} but this will work in earlier versions
eval font create TkBoldFont [font actual TkDefaultFont] -weight bold
buildUI
}
proc buildUI {} {
frame .toolbar
scrollbar .vsb -command [list .t yview]
text .t \
-width 80 -height 20 \
-yscrollcommand [list .vsb set] \
-highlightthickness 0
.t tag configure command -font TkBoldFont
.t tag configure error -font TkDefaultFont -foreground firebrick
.t tag configure output -font TkDefaultFont -foreground black
grid .toolbar -sticky nsew
grid .t .vsb -sticky nsew
grid rowconfigure . 1 -weight 1
grid columnconfigure . 0 -weight 1
set i 0
foreach {label command} {
date {date}
uptime {uptime}
ls {ls -l}
} {
button .b$i -text $label -command [list runCommand $command]
pack .b$i -in .toolbar -side left
incr i
}
}
proc output {type text} {
.t configure -state normal
.t insert end $text $type "\n"
.t see end
.t configure -state disabled
}
proc runCommand {cmd} {
output command $cmd
set f [open "| $cmd" r]
fconfigure $f -blocking false
fileevent $f readable [list handleFileEvent $f]
}
proc closePipe {f} {
# turn blocking on so we can catch any errors
fconfigure $f -blocking true
if {[catch {close $f} err]} {
output error $err
}
}
proc handleFileEvent {f} {
set status [catch { gets $f line } result]
if { $status != 0 } {
# unexpected error
output error $result
closePipe $f
} elseif { $result >= 0 } {
# we got some output
output normal $line
} elseif { [eof $f] } {
# End of file
closePipe $f
} elseif { [fblocked $f] } {
# Read blocked, so do nothing
}
}
main