28 lines
776 B
Racket
28 lines
776 B
Racket
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#lang typed/racket
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;;; dds/utils
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;;; Various utilities.
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(require (for-syntax syntax/parse))
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(provide auto-hash-ref/explicit)
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;;; HashTable Injection
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;;; This section of the file contains some utilities to streamline the
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;;; usage of hash tables mapping symbols to values. The goal is
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;;; essentially to avoid having to write explicit hash-ref calls.
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;;; Given a (HashTable Symbol a) and a sequence of symbols, binds
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;;; these symbols to the values they are associated to in the hash
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;;; table, then puts the body in the context of these bindings.
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(define-syntax (auto-hash-ref/explicit stx)
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(syntax-parse stx
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[(_ (ht:id xs:id ...) body:expr)
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#`(let #,(for/list ([x (syntax->list #'(xs ...))])
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#`[#,x (hash-ref ht '#,x)])
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body)]))
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