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cafa4c681e
and use a floating point timeout when calling select. Untested, since the regex library is currently AWOL.
127 lines
3.8 KiB
Scheme
127 lines
3.8 KiB
Scheme
;;; installed-scm-file
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;;;; Copyright (C) 1996 Free Software Foundation, Inc.
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;;;;
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;;;; This program is free software; you can redistribute it and/or modify
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;;;; it under the terms of the GNU General Public License as published by
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;;;; the Free Software Foundation; either version 2, or (at your option)
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;;;; any later version.
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;;;;
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;;;; This program is distributed in the hope that it will be useful,
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;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;;; GNU General Public License for more details.
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;;;;
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;;;; You should have received a copy of the GNU General Public License
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;;;; along with this software; see the file COPYING. If not, write to
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;;;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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;;;;
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;;; Expect: a macro for selecting actions based on what it reads from a port.
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;;; The idea is from Don Libes' expect based on Tcl.
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;;; This version by Gary Houston incorporating ideas from Aubrey Jaffer.
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(define expect-port #f)
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(define expect-timeout #f)
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(define expect-timeout-proc #f)
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(define expect-eof-proc #f)
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(define expect-char-proc #f)
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;;; expect: each test is a procedure which is applied to the accumulating
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;;; string.
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(defmacro expect clauses
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(let ((s (gentemp))
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(c (gentemp))
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(port (gentemp))
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(timeout (gentemp)))
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`(let ((,s "")
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(,port (or expect-port (current-input-port)))
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;; when timeout occurs, in floating point seconds.
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(,timeout (if expect-timeout
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(let* ((secs-usecs (gettimeofday)))
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(+ (car secs-usecs)
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expect-timeout
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(/ (cdr secs-usecs)
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1000000))) ; one million.
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#f)))
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(let next-char ()
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(if (and expect-timeout
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(or (>= (get-internal-real-time) ,timeout)
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(and (not (char-ready? ,port))
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(not (expect-select ,port ,timeout)))))
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(if expect-timeout-proc
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(expect-timeout-proc ,s)
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#f)
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(let ((,c (read-char ,port)))
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(if expect-char-proc
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(expect-char-proc ,c))
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(cond ((eof-object? ,c)
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(if expect-eof-proc
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(expect-eof-proc ,s)
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#f))
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(else
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(set! ,s (string-append ,s (string ,c)))
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(cond
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,@(let next-expr ((tests (map car clauses))
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(exprs (map cdr clauses))
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(body ()))
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(cond
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((null? tests)
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(reverse body))
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(else
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(next-expr
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(cdr tests)
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(cdr exprs)
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(cons
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`((,(car tests) ,s)
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,@(cond ((null? (car exprs))
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())
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((eq? (caar exprs) '=>)
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(if (not (= (length (car exprs))
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2))
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(scm-error 'misc-error
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"expect"
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"bad recipient: %S"
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(list (car exprs))
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#f)
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`((apply ,(cadar exprs)
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(,(car tests) ,s)))))
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(else
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(car exprs))))
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body)))))
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(else (next-char)))))))))))
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;;; the regexec front-end to expect:
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;;; each test must evaluate to a regular expression.
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(defmacro expect-strings clauses
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`(let ,@(let next-test ((tests (map car clauses))
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(exprs (map cdr clauses))
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(defs ())
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(body ()))
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(cond ((null? tests)
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(list (reverse defs) `(expect ,@(reverse body))))
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(else
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(let ((rxname (gentemp)))
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(next-test (cdr tests)
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(cdr exprs)
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(cons `(,rxname (regcomp ,(car tests)
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REG_NEWLINE))
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defs)
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(cons `((lambda (s)
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(regexec ,rxname s ""))
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,@(car exprs))
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body))))))))
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;;; simplified select: returns #t if input is waiting or #f if timed out.
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;;; timeout is an absolute time in floating point seconds.
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(define (expect-select port timeout)
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(let* ((secs-usecs (gettimeofday))
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(relative (- timeout
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(car secs-usecs)
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(/ (cdr secs-usecs)
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1000000)))) ; one million.
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(and (> relative 0)
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(pair? (car (select (list port) () ()
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relative))))))
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