e52fb81aac
with subsequent adaptation of (planet cce/scheme) to collects/unstable. These bindings are temporary, and will be replaced in the adaptation.
14 lines
328 B
Racket
14 lines
328 B
Racket
#lang racket/base
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(provide simple-hash-union)
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;; map map (key val val -> val) -> map
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(define (simple-hash-union h1 h2 f)
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(for/fold ([h* h1])
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([(k v2) h2])
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(let* ([v1 (hash-ref h1 k #f)]
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[new-val (if v1
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(f k v1 v2)
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v2)])
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(hash-set h* k new-val))))
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