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