[plt-scheme] A graphic toplevel

You should define a class, such as this lexer/parser%, which is a text%,
but define/override's the on-char method, commes ca:

(define lexer/parser%
  (class text%
    (super-instantiate ())
    (rename (on-char super-on-char))
    (define/override (on-char event)
      (define key (send event get-key-code))
      (if (or (equal? key #\return)
              (equal? key 'numpad-enter))
          (handle-return)
          (super-on-char)))))

This example assumes calls (handle-return) when return is pressed, and
works as a text% normally would on any other key.
It has not been tested; maybe the parenthesis are a bit wrong or I mixed
something up, but this is the general idea.

Good luck.

-----Original Message-----
From: The Computer Man [mailto:thecomputerman at wanadoo.fr] 
Sent: Wednesday, January 07, 2004 12:15 AM
To: plt-scheme at list.cs.brown.edu
Subject: [plt-scheme] A graphic toplevel

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Hello,

I'm writting an lexer/parser with a "toplevel" read-eval-loop. I can
replace
the toplevel scheme by this, and now i try to make it in graphic mode. I
find an idea with two editor-canvas and a button, i'm explain, in the
first
editor the user write the question, and when i want to eval this
question
he's click on the button and the result was written in the second
editor.

But i want to automatics this system like the toplevel of Scheme, when
the
user press enter the question was eval and written, but i can't find an
mred
objets who can do this.

Can you help me ?

Thanks for avancy for your answer.