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https://github.com/ashinn/chibi-scheme.git
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45 lines
1.6 KiB
Scheme
45 lines
1.6 KiB
Scheme
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(define-library (chibi optional)
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(export let-optionals let-optionals*
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opt-lambda opt-lambda*
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define-opt define-opt*
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let-keywords let-keywords*
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keyword-ref keyword-ref*)
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(cond-expand
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(chibi
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(import (chibi))
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(begin
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(define-syntax symbol->keyword*
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(er-macro-transformer
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(lambda (expr rename compare)
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(if (and (pair? (cdr expr)) (pair? (cadr expr))
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(compare 'quote (car (cadr expr))))
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`(,(rename 'quote)
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,(string->symbol
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(string-append
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(symbol->string
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(identifier->symbol (cadr (cadr expr)))) ":")))
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`(string->symbol
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(string-append (symbol->string ,(cadr expr)) ":"))))))))
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(else
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(import (scheme base))
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(begin
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(define-syntax let-optionals*
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(syntax-rules ()
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((let-optionals* opt-ls () . body)
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(begin . body))
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((let-optionals* (op . args) vars . body)
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(let ((tmp (op . args)))
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(let-optionals* tmp vars . body)))
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((let-optionals* tmp ((var default) . rest) . body)
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(let* ((tmp2 (if (pair? tmp) (cdr tmp) '()))
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(var (if (pair? tmp) (car tmp) default)))
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(let-optionals* tmp2 rest . body)))
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((let-optionals* tmp tail . body)
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(let ((tail (list-copy tmp))) . body))))
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(define-syntax symbol->keyword*
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(syntax-rules ()
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((symbol->keyword* sym)
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(string->symbol (string-append (symbol->string sym) ":")))
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)))))
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(include "optional.scm"))
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