scheme/tex-parser.scm

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(define (tex-command-char? ch)
(or (char-alphabetic? ch)
(char-numeric? ch)))
(define (not-tex-special-char? ch)
(not (or (equal? ch #\{)
(equal? ch #\})
(equal? ch #\\))))
(define (read-tex-command-args)
(let loop ((args '()))
(if (not (read-char? #\{))
args
(loop (append args (list (read-tex-until #\})))))))
(define (read-tex-thing)
(cond ((read-char? #\\)
(let ((command (read-char* tex-command-char?)))
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(if command
(cons (string->symbol command)
(read-tex-command-args))
(read-char* not-tex-special-char?))))
((read-char? #\{)
(cons 'math (read-tex-until #\})))
(else (read-char* not-tex-special-char?))))
(define (read-tex-until sentinel)
(let loop ((things '()))
(if (read-char? sentinel)
things
(let ((thing (read-tex-thing)))
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(if (not thing)
things
(loop (append things (list thing))))))))
(define (read-tex-document)
(read-tex-until eof-object?))