Re: retrieving line number in case of error - "simple debugger"

Nicolas Castagne wrote:
> Tcl is widely used to let end-users write scripts that impact a big
> C/C++ application.
> I myself currently develop a sort of modeler for physical models, that
> will involve both a GUI and a Tcl-based end-user language.
>
> The Tcl-based language will let the user decribe the model, by calling C
> routine that will build the model in memory (hope it is clear enough).
> The scripts will be written within a text canvas holded by the GUI, and
> interpreted through a TclInterp ran by the GUI.

In such a case, you have complete control over the execution of the
code. You can, for instance, tell the user which line of the
user-entered script has an error with something like this:

set script [.text get 1.0 end-1c]
set lineno 0
foreach line [split $script \n] {
     if {![info exists command]} {
         set command $line
     } else {
         append command \n $line
     }
     incr lineno
     if {[info complete $command]} {
         if {[catch $command err]} {
             puts "error on line $lineno: $err"
         }
         unset command
     }
}

That isn't precise, but it gives you a rough idea.

With a bit more code you can highlight the code in the text widget that
is about to be executed, and have buttons on a toolbar that cause the
code to be executed or stepped over, one line at a time.

So, perhaps the answer to your question is "info complete" and "catch".
That is, you can use [info complete] to know if a line or lines of
user-entered text is a complete command, and "catch" to execute the
command and to retrieve the result.
Received on Sat Oct 15 03:53:41 2005