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138 lines
3.1 KiB
Racket
138 lines
3.1 KiB
Racket
#lang racket/base
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(require rackunit
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(for-syntax racket/base))
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;; The tests in this module make sure we produce proper error messages
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;; on weird grammars.
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(define-namespace-anchor anchor)
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(define ns (namespace-anchor->namespace anchor))
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(define (c prog)
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(parameterize ([current-namespace ns]
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[read-accept-reader #t])
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(define ip (open-input-string prog))
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(port-count-lines! ip)
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(compile (read-syntax #f ip))))
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;; Helper to let me quickly write compile-error checks.
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(define-syntax (check-compile-error stx)
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(syntax-case stx ()
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[(_ prog expected-msg)
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(quasisyntax/loc stx
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(begin #,(syntax/loc stx
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(check-exn (regexp (regexp-quote expected-msg))
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(lambda ()
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(c prog))))
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#,(syntax/loc stx
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(check-exn exn:fail:syntax?
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(lambda ()
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(c prog))))))]))
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;; errors with position are sensitive to length of lang line
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(define lang-line "#lang brag")
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(check-compile-error (format "~a" lang-line)
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"The grammar does not appear to have any rules")
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(check-compile-error (format "~a\nfoo" lang-line)
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"Error while parsing grammar near: foo [line=2, column=0, position=12]")
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(check-compile-error (format "~a\nnumber : 42" lang-line)
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"Error while parsing grammar near: 42 [line=2, column=9, position=21]")
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(check-compile-error (format "~a\nnumber : 1" lang-line)
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"Error while parsing grammar near: 1 [line=2, column=9, position=21]")
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(check-compile-error "#lang brag\n x: NUMBER\nx:STRING"
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"Rule x has a duplicate definition")
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;; Check to see that missing definitions for rules also raise good syntax
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;; errors:
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(check-compile-error "#lang brag\nx:y"
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"Rule y has no definition")
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(check-compile-error "#lang brag\nnumber : 1flarbl"
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"Rule 1flarbl has no definition")
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(check-compile-error "#lang brag\nprogram: EOF"
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"Token EOF is reserved and can not be used in a grammar")
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;; Nontermination checks:
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(check-compile-error "#lang brag\nx : x"
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"Rule x has no finite derivation")
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(check-compile-error #<<EOF
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#lang brag
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x : x y
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y : "y"
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EOF
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"Rule x has no finite derivation")
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; This should be illegal too:
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(check-compile-error #<<EOF
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#lang brag
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a : "a" b
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b : a | b
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EOF
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"Rule a has no finite derivation")
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(check-compile-error #<<EOF
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#lang brag
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a : [b]
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b : [c]
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c : c
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EOF
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"Rule c has no finite derivation")
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(check-compile-error #<<EOF
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#lang brag
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a : [b]
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b : c
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c : c
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EOF
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"Rule b has no finite derivation")
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(check-compile-error #<<EOF
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#lang brag
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a : [a]
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b : [b]
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c : c
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EOF
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"Rule c has no finite derivation")
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(check-compile-error #<<EOF
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#lang racket/base
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(require brag/examples/simple-line-drawing)
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(define bad-parser (make-rule-parser crunchy))
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EOF
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"Rule crunchy is not defined in the grammar"
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)
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