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<article> <h2>Scheme mode</h2> <form><textarea id=“code” name=“code”> ; See if the input starts with a given symbol. (define (match-symbol input pattern)

(cond ((null? (remain input)) #f)
      ((eqv? (car (remain input)) pattern) (r-cdr input))
      (else #f)))

; Allow the input to start with one of a list of patterns. (define (match-or input pattern)

(cond ((null? pattern) #f)
      ((match-pattern input (car pattern)))
      (else (match-or input (cdr pattern)))))

; Allow a sequence of patterns. (define (match-seq input pattern)

(if (null? pattern)
    input
    (let ((match (match-pattern input (car pattern))))
      (if match (match-seq match (cdr pattern)) #f))))

; Match with the pattern but no problem if it does not match. (define (match-opt input pattern)

(let ((match (match-pattern input (car pattern))))
  (if match match input)))

; Match anything (other than '()), until pattern is found. The rather ; clumsy form of requiring an ending pattern is needed to decide where ; the end of the match is. If none is given, this will match the rest ; of the sentence. (define (match-any input pattern)

(cond ((null? (remain input)) #f)
      ((null? pattern) (f-cons (remain input) (clear-remain input)))
      (else
       (let ((accum-any (collector)))
         (define (match-pattern-any input pattern)
           (cond ((null? (remain input)) #f)
                 (else (accum-any (car (remain input)))
                       (cond ((match-pattern (r-cdr input) pattern))
                             (else (match-pattern-any (r-cdr input) pattern))))))
         (let ((retval (match-pattern-any input (car pattern))))
           (if retval
               (f-cons (accum-any) retval)
               #f))))))

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  <p><strong>MIME types defined:</strong> <code>text/x-scheme</code>.</p>

</article>