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73 lines
2.1 KiB
Racket
73 lines
2.1 KiB
Racket
#lang racket/base
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(require brag/examples/simple-arithmetic-grammar
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brag/support
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racket/set
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br-parser-tools/lex
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racket/list
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rackunit)
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(define (tokenize ip)
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(port-count-lines! ip)
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(define lex/1
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(lexer-src-pos
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[(repetition 1 +inf.0 numeric)
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(token 'INT (string->number lexeme))]
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[whitespace
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(token 'WHITESPACE #:skip? #t)]
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["+"
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(token '+ "+")]
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["*"
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(token '* "*")]
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[(eof)
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(token eof)]))
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(lambda ()
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(lex/1 ip)))
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;; expr : term ('+' term)*
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;; term : factor (('*') factor)*
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;; factor : INT
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(check-equal? (syntax->datum (parse #f (tokenize (open-input-string "42"))))
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'(expr (term (factor 42))))
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(check-equal? (syntax->datum (parse #f (tokenize (open-input-string "3+4"))))
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'(expr (term (factor 3))
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"+"
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(term (factor 4))))
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(check-equal? (syntax->datum (parse #f (tokenize (open-input-string "3+4+5"))))
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'(expr (term (factor 3))
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"+"
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(term (factor 4))
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"+"
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(term (factor 5))))
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(check-equal? (syntax->datum (parse #f (tokenize (open-input-string "3*4*5"))))
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'(expr (term (factor 3) "*" (factor 4) "*" (factor 5))))
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(check-equal? (syntax->datum (parse #f (tokenize (open-input-string "3*4 + 5*6"))))
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'(expr (term (factor 3) "*" (factor 4))
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"+"
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(term (factor 5) "*" (factor 6))))
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(check-equal? (syntax->datum (parse #f (tokenize (open-input-string "4*5+6"))))
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'(expr (term (factor 4) "*" (factor 5))
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"+"
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(term (factor 6))))
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(check-equal? (syntax->datum (parse #f (tokenize (open-input-string "4+5 *6"))))
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'(expr (term (factor 4))
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"+"
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(term (factor 5) "*" (factor 6))))
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(check-exn exn:fail:parsing?
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(lambda () (parse #f (tokenize (open-input-string "7+")))))
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(check-exn exn:fail:parsing?
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(lambda () (parse #f (tokenize (open-input-string "7+6+")))))
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(check-equal? all-token-types
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(set '+ '* 'INT))
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