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40 lines
1.6 KiB
Racket
40 lines
1.6 KiB
Racket
#lang racket/base
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(require brag/support)
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(provide current-source
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current-parser-error-handler
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current-tokenizer-error-handler)
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;; During parsing, we should define the source of the input.
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(define current-source (make-parameter 'unknown))
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;; When an parse error happens, we call the current-parser-error-handler:
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(define current-parser-error-handler
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(make-parameter
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(lambda (tok-name tok-value offset line col span)
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(raise (exn:fail:parsing
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(format "Encountered parsing error near ~e (token ~e) while parsing ~e [line=~a, column=~a, offset=~a]"
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tok-value tok-name
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(current-source)
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line col offset)
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(current-continuation-marks)
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(list (srcloc (current-source) line col offset span)))))))
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;; When a tokenization error happens, we call the current-tokenizer-error-handler.
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(define current-tokenizer-error-handler
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(make-parameter
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(lambda (tok-type tok-value offset line column span)
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(raise (exn:fail:parsing
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(string-append
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(format "Encountered unexpected token of type ~e (value ~e) while parsing"
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(if (memq tok-type (map string->symbol '("\n" "\t" "\r")))
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(format "~a" tok-type)
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tok-type) tok-value)
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(if (or (current-source) line column offset)
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(format " ~e [line=~a, column=~a, offset=~a]" (current-source) line column offset)
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""))
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(current-continuation-marks)
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(list (srcloc (current-source) line column offset span)))))))
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