51 lines
1.5 KiB
Racket
51 lines
1.5 KiB
Racket
#lang racket/base
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(require (for-syntax racket/base racket/list))
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(provide (rename-out [kaitai:module-begin #%module-begin])
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(except-out (all-from-out racket/base) #%module-begin))
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;; meow
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;; makes a syntax error raiser
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(define-for-syntax (rse msg)
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(lambda () (raise-syntax-error #f msg)))
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;; converts a ksy id to a racket id
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;; maps _ to -
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(define-for-syntax (kaitai-str->sym str)
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(string->symbol (regexp-replace* #px"_" str "-")))
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;; generates struct definitions
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(define-for-syntax (gen-struct top [given-id #f])
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(define id (or given-id (hash-ref (hash-ref top "meta" (hash)) "id"
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(rse "type has no meta.id and none was provided"))))
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(define id-sym (kaitai-str->sym id))
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(define seq (hash-ref top "seq" (rse "form must have a seq element")))
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(define instances (hash-ref top "instances" (hash)))
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#`((provide [struct-out #,id-sym])
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(struct #,id-sym
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[#,@(map (lambda (a) (kaitai-str->sym (hash-ref a "id" (rse "seq element has no id"))))
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seq)] #:transparent)))
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;; language infrastructure
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(define-syntax (kaitai:module-begin stx)
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(define body (second (syntax-e stx)))
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(define top-struct (gen-struct (syntax->datum body)))
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; (displayln top-struct)
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#`(#%module-begin
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#,@top-struct))
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(module reader syntax/module-reader
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#:read kaitai-read
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#:read-syntax kaitai-read
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#:language 'kaitai
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(require yaml)
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(define (kaitai-read path port)
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(or (read-yaml port) eof))
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(define (kaitai-read-syntax path port)
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(datum->syntax #f (kaitai-read path port))))
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