29 lines
818 B
Standard ML
29 lines
818 B
Standard ML
structure Scanner =
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struct
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structure Dfa = CaseSesitiveDfa
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val intDfa = Dfa.fromString "[0-9]+"
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val wordDfa = Dfa.fromString "0w[0-9]+"
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val realDfa = "[0-9]+.[0-9]+"
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val idDfa = Dfa.fromString "[a-zA-Z][a-zA-Z0-9_']*"
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fun helpExtractString (pos, str, acc) =
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if pos >= String.size str then
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raise Fail ("unterminated string: [" ^ acc ^ "]\n")
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else
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case String.sub (str, pos) of
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#"\"" => (pos + 1, acc)
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| #"\\" =>
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if pos + 1 >= String.size str then
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raise Fail ("unterminated string: [" ^ acc ^ "\\]\n")
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else
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(
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case String.sub (str, pos + 1) of
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)
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| chr =>
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helpExtractString (pos + 1, str, acc ^ String.implode [chr])
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fun extractString (pos, str) = helpExtractString (pos. str, "")
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end
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