78 lines
2.9 KiB
Plaintext
78 lines
2.9 KiB
Plaintext
;;;;
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;;;; l i s t e n e r . s t k -- A listener "widget"
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;;;;
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;;;;
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;;;; Copyright © 1993-1997 Erick Gallesio - I3S-CNRS/ESSI <eg@unice.fr>
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;;;;
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;;;; Permission to use, copy, and/or distribute this software and its
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;;;; documentation for any purpose and without fee is hereby granted, provided
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;;;; that both the above copyright notice and this permission notice appear in
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;;;; all copies and derived works. Fees for distribution or use of this
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;;;; software or derived works may only be charged with express written
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;;;; permission of the copyright holder.
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;;;; This software is provided ``as is'' without express or implied warranty.
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;;;;
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;;;; Author: Erick Gallesio [eg@unice.fr]
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;;;; Creation date: 11-Sep-1995 10:16
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;;;; Last file update: 27-Aug-1997 19:08
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(select-module Tk)
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;;;; Listener
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;;;; A new widget which is dedicated to interactive I/O. We have 4 new options:
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;;;; :prompt (">")
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;;;; :prompt-color ("red")
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;;;; :output-color ("blue")
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;;;; :command (a lambda which does nothing)
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;;;; The command is executed when a Return is typed in and a complete Sexpr
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;;;; has been entered between the last prompt and the return.
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(define (listener name . args)
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(let* ((prompt-color (get-keyword :prompt-color args "red"))
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(output-color (get-keyword :output-color args "blue"))
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(prompt (get-keyword :prompt args "> "))
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(command (get-keyword :command args (lambda (x) x))))
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(define (insert-prompt w)
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(w 'insert "end" prompt "list-prompt" " ")
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;; Add a mark to the current position
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(w 'mark 'set "start_expr" "end-1c")
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(w 'mark 'gravity "start_expr" "left")
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(w 'see "end"))
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(define (enter-expression w action) ;; Called when user type <Return>
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(let ((txt (w 'get "start_expr" "insert"))
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(exp '()))
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(if (or (catch (set! exp (read-from-string txt))) (eof-object? exp))
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;; Current expression is not complete
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'continue
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;; We have found an expression which seems complete.
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(let ((user-result (apply action (list txt))))
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(w 'insert "insert" "\n" "" user-result "list-output" "\n" "")
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(insert-prompt w)
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'break))))
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(unless (= (modulo (length args) 2) 0)
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(error "listener: argument list size is not even ~S" args))
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;; Build a list of valid Tk arguments
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(let ((tk-args '()))
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(do ((args args (cddr args)))
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((null? args))
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(unless (member (car args) '(:prompt-color :output-color :prompt :command))
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(set! tk-args (append tk-args (list (car args) (cadr args))))))
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;; Create a text Tk-command with given arguments
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(let ((w (apply Tk:text name tk-args)))
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(bind w "<Return>" (lambda () (enter-expression w command)))
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(w 'tag 'configure "list-prompt" :foreground prompt-color)
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(w 'tag 'configure "list-output" :foreground output-color)
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(insert-prompt w)
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w))))
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(define (listener-insert-string w str)
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(w 'insert "start_expr linestart" str "list-output")
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(w 'see "insert"))
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(provide "listener")
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