30 lines
2.0 KiB
Plaintext
30 lines
2.0 KiB
Plaintext
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(with_import "./collections.kp"
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(let (
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match (vau de (x & cases) (let (
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x (eval x de)
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evaluate_case (rec-lambda recurse (name_dict x c) (cond
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; an explicit nil name_dict case allows us to simply fold over recurse in the array case later
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(nil? name_dict) nil
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(symbol? c) (put name_dict c x)
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(and (int? x) (int? c) (= x c)) name_dict
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(and (string? x) (string? c) (= x c)) name_dict
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(and (bool? x) (bool? c) (= x c)) name_dict
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(and (combiner? x) (combiner? c) (= x c)) name_dict
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; check for invocation of quote directly
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; not necessarily ideal if they define their own quote or something
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(and (symbol? x) (array? c) (= 2 (len c)) (= quote (idx c 0)) (= x (idx c 1))) name_dict
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; ditto with above, but with array
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(and (array? x) (array? c) (= (+ 1 (len x)) (len c)) (= array (idx c 0))) (foldl recurse name_dict x (slice c 1 -1))
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true nil
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))
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iter (rec-lambda recurse (x i cases) (if (>= i (len cases)) (error "none of match arms matched!")
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(let ( mapping (evaluate_case empty_dict x (idx cases i)))
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(if (!= nil mapping) (eval (idx cases (+ i 1)) (add-dict-to-env de mapping))
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(recurse x (+ i 2) cases)))))
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) (iter x 0 cases)))
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)
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(provide match)
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))
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