mirror of
https://github.com/ashinn/chibi-scheme.git
synced 2025-05-19 13:49:17 +02:00
45 lines
1.4 KiB
Scheme
45 lines
1.4 KiB
Scheme
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;; let-optionals* is in the core
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(define-syntax let*-to-let
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(syntax-rules ()
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((let*-to-let letstar ls (vars ...) ((v . d) . rest) . body)
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(let*-to-let letstar ls (vars ... (v tmp . d)) rest . body))
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((let*-to-let letstar ls ((var tmp . d) ...) rest . body)
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(letstar ls ((tmp . d) ... . rest)
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(let ((var tmp) ...) . body)))))
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(define-syntax let-optionals
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(syntax-rules ()
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((let-optionals ls vars . body)
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(let*-to-let let-optionals* ls () vars . body))))
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(define-syntax opt-lambda
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(syntax-rules ()
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((opt-lambda vars . body)
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(lambda args (let-optionals args vars . body)))))
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(define (keyword-ref ls key . o)
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(cond ((memq key ls) => cadr)
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(else (and (pair? o) (car o)))))
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(define-syntax let-keywords*
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(syntax-rules ()
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((let-keywords* opt-ls () . body)
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(begin . body))
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((let-keywords* (op . args) vars . body)
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(let ((tmp (op . args)))
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(let-keywords* tmp vars . body)))
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((let-keywords* opt-ls ((var default) . rest) . body)
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(let ((var (keyword-ref opt-ls 'var default)))
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(let-keywords* opt-ls rest . body)))
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((let-keywords* opt-ls ((var key default) . rest) . body)
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(let ((var (keyword-ref opt-ls 'key default)))
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(let-keywords* opt-ls rest . body)))
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((let-keywords* opt-ls tail . body)
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(let ((tail opt-ls)) . body))))
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(define-syntax let-keywords
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(syntax-rules ()
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((let-keywords ls vars . body)
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(let*-to-let let-keywords* ls () vars . body))))
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