873 lines
28 KiB
Standard ML
873 lines
28 KiB
Standard ML
signature DFA_GEN_PARAMS =
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sig
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val endMarker: char
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val charIsEqual: char * char -> bool
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val charIsNotEqual: char * char -> bool
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end
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signature DFA_GEN =
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sig
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type dfa = int vector vector
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type dfa_state = int
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val fromString: string -> dfa
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val nextState: dfa * dfa_state * char -> dfa_state
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val isFinal: dfa * dfa_state -> bool
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val isDead: dfa_state -> bool
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val matchString: dfa * string -> (int * int) list
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end
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functor MakeDfaGen(Fn: DFA_GEN_PARAMS): DFA_GEN =
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struct
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datatype parse_tree =
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CHAR_LITERAL of {char: char, position: int}
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| WILDCARD of int
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| IS_ANY_CHARACTER of {chars: char vector, position: int}
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| NOT_ANY_CHARACTER of {chars: char vector, position: int}
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| CONCAT of
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{l: parse_tree, r: parse_tree, leftMaxState: int, rightMaxState: int}
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| ALTERNATION of
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{l: parse_tree, r: parse_tree, leftMaxState: int, rightMaxState: int}
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| ZERO_OR_ONE of parse_tree
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| ZERO_OR_MORE of parse_tree
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| ONE_OR_MORE of parse_tree
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| GROUP of parse_tree
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structure Set =
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struct
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datatype 'a set = BRANCH of 'a set * int * 'a * 'a set | LEAF
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fun insertOrReplace (newKey, newVal, tree) =
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case tree of
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BRANCH (l, curKey, curVal, r) =>
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if newKey > curKey then
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let val r = insertOrReplace (newKey, newVal, r)
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in BRANCH (l, curKey, curVal, r)
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end
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else if newKey < curKey then
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let val l = insertOrReplace (newKey, newVal, l)
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in BRANCH (l, curKey, curVal, r)
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end
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else
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BRANCH (l, newKey, newVal, r)
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| LEAF => BRANCH (LEAF, newKey, newVal, LEAF)
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fun getOrDefault (findKey, tree, default) =
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case tree of
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BRANCH (l, curKey, curVal, r) =>
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if findKey > curKey then getOrDefault (findKey, r, default)
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else if findKey < curKey then getOrDefault (findKey, l, default)
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else curVal
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| LEAF => default
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fun helpToList (tree, acc) =
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case tree of
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BRANCH (l, curKey, curVal, r) =>
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let
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val acc = helpToList (r, acc)
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val acc = (curKey, curVal) :: acc
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in
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helpToList (l, acc)
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end
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| LEAF => acc
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fun toList tree = helpToList (tree, [])
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fun helpKeysToList (tree, acc) =
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case tree of
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BRANCH (l, curKey, _, r) =>
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let
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val acc = helpKeysToList (r, acc)
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val acc = curKey :: acc
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in
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helpKeysToList (l, acc)
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end
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| LEAF => acc
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fun keysToList tree = helpKeysToList (tree, [])
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fun map (f, tree) =
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case tree of
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BRANCH (l, key, value, r) =>
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let
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val r = map (f, r)
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val l = map (f, l)
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val value = f value
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in
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BRANCH (l, key, value, r)
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end
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| LEAF => LEAF
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fun foldl (f, tree, acc) =
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case tree of
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BRANCH (l, k, v, r) =>
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let
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val acc = foldl (f, l, acc)
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val acc = f (v, acc)
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in
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foldl (f, r, acc)
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end
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| LEAF => acc
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end
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structure ParseDfa =
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struct
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(* parsing through precedence climbing algorithm. *)
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val postfixLevel = 1
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val concatLevel = 2
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val altLevel = 3
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local
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fun loop (pos, str, openParens, closeParens) =
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if pos = String.size str then
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NONE
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else
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case String.sub (str, pos) of
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#"(" => loop (pos + 1, str, openParens + 1, closeParens)
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| #")" =>
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if closeParens + 1 = openParens then SOME pos
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else loop (pos + 1, str, openParens, closeParens + 1)
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| _ => loop (pos + 1, str, openParens, closeParens)
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in
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fun getRightParenIdx (pos, str) = loop (pos, str, 1, 0)
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end
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(* assumes previous char is a backslash *)
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fun isValidEscapeSequence chr =
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case chr of
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(* regex metacharacters *)
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#"(" => (true, chr)
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| #")" => (true, chr)
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| #"[" => (true, chr)
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| #"]" => (true, chr)
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| #"+" => (true, chr)
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| #"*" => (true, chr)
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| #"|" => (true, chr)
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| #"?" => (true, chr)
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| #"." => (true, chr)
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| #"-" => (true, chr)
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(* standard escape sequences *)
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| #"a" => (true, #"\a")
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| #"b" => (true, #"\b")
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| #"t" => (true, #"\t")
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| #"n" => (true, #"\n")
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| #"v" => (true, #"\v")
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| #"f" => (true, #"\f")
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| #"r" => (true, #"\r")
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| #"\\" => (true, chr)
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| _ => (false, chr)
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fun getCharsBetween (lowChr, highChr, acc) =
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if lowChr = highChr then
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highChr :: acc
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else
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let
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val acc = lowChr :: acc
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val lowChr = Char.succ lowChr
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in
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getCharsBetween (lowChr, highChr, acc)
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end
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fun getCharsInBrackets (pos, str, acc) =
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if pos = String.size str then
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NONE
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else
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case String.sub (str, pos) of
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#"\\" =>
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(* escape sequences *)
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if pos + 1 = String.size str then
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NONE
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else
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let
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val chr = String.sub (str, pos + 1)
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val (isValid, chr) = isValidEscapeSequence chr
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in
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if isValid then
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(* Edge case:
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* We have to check if there is a char range like a-z,
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* and if there is,
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* we have to check if the second char in the range
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* is another escaped-character *)
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if
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pos + 2 < String.size str
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andalso String.sub (str, pos + 2) = #"-"
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andalso pos + 3 < String.size str
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then
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(* we do have a character range,
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* which may possibly be escaped *)
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case String.sub (str, pos + 3) of
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#"(" => NONE
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| #")" => NONE
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| #"[" => NONE
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| #"]" => NONE
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| #"+" => NONE
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| #"*" => NONE
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| #"|" => NONE
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| #"?" => NONE
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| #"." => NONE
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| #"-" => NONE
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| #"\\" =>
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if pos + 4 < String.size str then
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let
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val chr2 = String.sub (str, pos + 4)
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val (isValid, chr2) = isValidEscapeSequence chr2
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val acc =
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if chr < chr2 then
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getCharsBetween (chr, chr2, acc)
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else
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getCharsBetween (chr2, chr, acc)
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in
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getCharsInBrackets (pos + 5, str, acc)
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end
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else
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NONE
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| chr2 =>
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let
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val acc =
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if chr < chr2 then getCharsBetween (chr, chr2, acc)
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else getCharsBetween (chr2, chr, acc)
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in
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getCharsInBrackets (pos + 4, str, acc)
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end
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else
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(* no character range we have to check *)
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getCharsInBrackets (pos + 2, str, chr :: acc)
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else
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NONE
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end
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| #"]" =>
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let val chars = Vector.fromList acc
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in SOME (pos + 1, chars)
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end
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| #"-" => NONE
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| chr =>
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if
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pos + 1 < String.size str andalso String.sub (str, pos + 1) = #"-"
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andalso pos + 2 < String.size str
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then
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(* handle character ranges like a-z.
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* There are edge cases regarding
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* the second character in the range.
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* We have to check that any unescaped metacharacters
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* return an invalid parse state.
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* We also have to unescape any escape sequences.
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* *)
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case String.sub (str, pos + 2) of
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#"\\" =>
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(* second char contains an escape sequence *)
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if pos + 3 < String.size str then
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let
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val chr2 = String.sub (str, pos + 3)
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val (isValid, chr2) = isValidEscapeSequence chr2
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val acc =
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if chr < chr2 then getCharsBetween (chr, chr2, acc)
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else getCharsBetween (chr2, chr, acc)
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in
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if isValid then getCharsInBrackets (pos + 4, str, acc)
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else NONE
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end
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else
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NONE
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| #"(" => NONE
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| #")" => NONE
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| #"[" => NONE
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| #"]" => NONE
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| #"+" => NONE
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| #"*" => NONE
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| #"|" => NONE
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| #"?" => NONE
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| #"." => NONE
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| #"-" => NONE
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| chr2 =>
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(* valid char range *)
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let
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val acc =
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if chr < chr2 then getCharsBetween (chr, chr2, acc)
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else getCharsBetween (chr2, chr, acc)
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in
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getCharsInBrackets (pos + 3, str, acc)
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end
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else
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getCharsInBrackets (pos + 1, str, chr :: acc)
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fun parseCharacterClass (pos, str, stateNum) =
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case getCharsInBrackets (pos, str, []) of
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SOME (pos, chars) =>
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let
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val node = IS_ANY_CHARACTER {chars = chars, position = stateNum + 1}
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in
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SOME (pos, node, stateNum + 1)
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end
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| NONE => NONE
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fun parseNegateCharacterClass (pos, str, stateNum) =
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case getCharsInBrackets (pos, str, []) of
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SOME (pos, chars) =>
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let
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val node =
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NOT_ANY_CHARACTER {chars = chars, position = stateNum + 1}
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in
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SOME (pos, node, stateNum + 1)
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end
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| NONE => NONE
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fun computeAtom (pos, str, stateNum) =
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if pos = String.size str then
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NONE
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else
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case String.sub (str, pos) of
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#"(" =>
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(case getRightParenIdx (pos + 1, str) of
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SOME groupEndIdx =>
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let
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val substr = String.substring
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(str, pos + 1, groupEndIdx - pos - 1)
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in
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case parse (substr, stateNum) of
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SOME (rhs, stateNum) =>
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SOME (groupEndIdx + 1, rhs, stateNum)
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| NONE => NONE
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end
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| NONE => NONE)
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| #"\\" =>
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(* escape sequences *)
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if pos + 1 = String.size str then
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NONE
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else
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let
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val chr = String.sub (str, pos + 1)
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val (isValid, chr) = isValidEscapeSequence chr
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in
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if Fn.charIsEqual (chr, Fn.endMarker) then
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NONE
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else if isValid then
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let
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val chr = CHAR_LITERAL {char = chr, position = stateNum + 1}
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in
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SOME (pos + 2, chr, stateNum + 1)
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end
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else
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NONE
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end
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| #"." => SOME (pos + 1, WILDCARD (stateNum + 1), stateNum + 1)
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| #")" => NONE
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| #"?" => NONE
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| #"*" => NONE
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| #"+" => NONE
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| #"[" =>
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if pos + 1 = String.size str then
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NONE
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else if String.sub (str, pos + 1) = #"^" then
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parseNegateCharacterClass (pos + 2, str, stateNum)
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else
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parseCharacterClass (pos + 1, str, stateNum)
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| chr =>
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if Fn.charIsEqual (chr, Fn.endMarker) then
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NONE
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else
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let val chr = CHAR_LITERAL {char = chr, position = stateNum + 1}
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in SOME (pos + 1, chr, stateNum + 1)
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end
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and climb (pos, str, lhs, level, stateNum) : (int * parse_tree * int) option =
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if pos = String.size str then
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SOME (pos, lhs, stateNum)
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else
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case String.sub (str, pos) of
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#"|" =>
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if level < altLevel then
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SOME (pos, lhs, stateNum)
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else if pos + 1 < String.size str then
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let
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val chr = String.sub (str, pos + 1)
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val chr = CHAR_LITERAL {char = chr, position = stateNum + 1}
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in
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case climb (pos + 2, str, chr, altLevel, stateNum + 1) of
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SOME (pos, rhs, rightStateNum) =>
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let
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val result = ALTERNATION
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{ l = lhs
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, r = rhs
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, leftMaxState = stateNum
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, rightMaxState = rightStateNum
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}
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in
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SOME (pos, result, rightStateNum)
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end
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| NONE => NONE
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end
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else
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NONE
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| #"?" =>
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if level < postfixLevel then
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SOME (pos, lhs, stateNum)
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else
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let val lhs = ZERO_OR_ONE lhs
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in climb (pos + 1, str, lhs, postfixLevel, stateNum)
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end
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| #"*" =>
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if level < postfixLevel then
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SOME (pos, lhs, stateNum)
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else
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let val lhs = ZERO_OR_MORE lhs
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in climb (pos + 1, str, lhs, postfixLevel, stateNum)
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end
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| #"+" =>
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if level < postfixLevel then
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SOME (pos, lhs, stateNum)
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else
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let val lhs = ONE_OR_MORE lhs
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in climb (pos + 1, str, lhs, postfixLevel, stateNum)
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end
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| chr =>
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if level < concatLevel then
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SOME (pos, lhs, stateNum)
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else
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case computeAtom (pos, str, stateNum) of
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SOME (nextPos, curAtom, atomStateNum) =>
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(case climb (nextPos, str, curAtom, concatLevel, atomStateNum) of
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SOME (pos, rhs, rightStateNum) =>
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let
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val result = CONCAT
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{ l = lhs
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, r = rhs
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, leftMaxState = stateNum
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, rightMaxState = rightStateNum
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}
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in
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SOME (pos, result, rightStateNum)
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end
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| NONE => NONE)
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| NONE => NONE
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and loop (pos, str, ast, stateNum) =
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if pos = String.size str then
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SOME (ast, stateNum)
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else
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case climb (pos, str, ast, altLevel, stateNum) of
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SOME (pos, ast, stateNum) => loop (pos, str, ast, stateNum)
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| NONE => NONE
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and parse (str, stateNum) =
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if String.size str > 0 then
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case computeAtom (0, str, stateNum) of
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SOME (nextPos, lhs, stateNum) => loop (nextPos, str, lhs, stateNum)
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| NONE => NONE
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else
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NONE
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end
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|
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structure ToDfa =
|
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struct
|
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fun isNullable tree =
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case tree of
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CHAR_LITERAL _ => false
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| WILDCARD _ => false
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| IS_ANY_CHARACTER _ => false
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| NOT_ANY_CHARACTER _ => false
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| CONCAT {l, r, ...} => isNullable l andalso isNullable r
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| ALTERNATION {l, r, ...} => isNullable l orelse isNullable r
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| ZERO_OR_ONE _ => true
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| ZERO_OR_MORE _ => true
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| ONE_OR_MORE regex => isNullable regex
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| GROUP regex => isNullable regex
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fun firstpos (tree, acc) =
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case tree of
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CHAR_LITERAL {position, ...} => position :: acc
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| IS_ANY_CHARACTER {position, ...} => position :: acc
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| NOT_ANY_CHARACTER {position, ...} => position :: acc
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| WILDCARD i => i :: acc
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|
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| CONCAT {l, r, ...} =>
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if isNullable l then
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let val acc = firstpos (l, acc)
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in firstpos (r, acc)
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end
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else
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firstpos (l, acc)
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| ALTERNATION {l, r, ...} =>
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let val acc = firstpos (l, acc)
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in firstpos (r, acc)
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end
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|
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| ZERO_OR_ONE regex => firstpos (regex, acc)
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| ZERO_OR_MORE regex => firstpos (regex, acc)
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| ONE_OR_MORE regex => firstpos (regex, acc)
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| GROUP regex => firstpos (regex, acc)
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fun lastpos (tree, acc) =
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case tree of
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CHAR_LITERAL {position, ...} => position :: acc
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| IS_ANY_CHARACTER {position, ...} => position :: acc
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| NOT_ANY_CHARACTER {position, ...} => position :: acc
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| WILDCARD i => i :: acc
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| CONCAT {l, r, ...} =>
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if isNullable r then
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let val acc = lastpos (l, acc)
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in lastpos (r, acc)
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end
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else
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lastpos (r, acc)
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| ALTERNATION {l, r, ...} =>
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let val acc = lastpos (l, acc)
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in lastpos (r, acc)
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end
|
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|
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| ZERO_OR_ONE regex => lastpos (regex, acc)
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| ZERO_OR_MORE regex => lastpos (regex, acc)
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| ONE_OR_MORE regex => lastpos (regex, acc)
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| GROUP regex => lastpos (regex, acc)
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fun followpos (char, regex, acc) =
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case regex of
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CONCAT {r, ...} => firstpos (r, acc)
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| ZERO_OR_MORE r => firstpos (r, acc)
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| ONE_OR_MORE r => firstpos (r, acc)
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| _ => acc
|
|
|
|
fun chrExistsInVec (idx, vec, curChr) =
|
|
if idx = Vector.length vec then
|
|
false
|
|
else
|
|
let
|
|
val idxChr = Vector.sub (vec, idx)
|
|
in
|
|
Fn.charIsEqual (idxChr, curChr)
|
|
orelse chrExistsInVec (idx + 1, vec, curChr)
|
|
end
|
|
|
|
(* Does two things:
|
|
* 1. Descends to the leaf matching 'pos'.
|
|
* 2. If the character at 'pos' matches the current character,
|
|
* calls followpos at the appropriate nodes.
|
|
* In the end, we get a list of positions to follow.
|
|
* Note: The character #"\^@" is an endmarker
|
|
* indicating that this is the final state.
|
|
* We say that there is no match,
|
|
* even if the curChr is the endmarker. *)
|
|
fun getFollowsForPositionAndChar (regex: parse_tree, pos, curChr) =
|
|
case regex of
|
|
CHAR_LITERAL {char, position = _} =>
|
|
let val charIsMatch = Fn.charIsEqual (char, curChr)
|
|
in {sawConcat = false, follows = [], charIsMatch = charIsMatch}
|
|
end
|
|
| WILDCARD _ =>
|
|
let val isNotEndmarker = Fn.charIsNotEqual (curChr, Fn.endMarker)
|
|
in {sawConcat = false, follows = [], charIsMatch = isNotEndmarker}
|
|
end
|
|
| IS_ANY_CHARACTER {chars, ...} =>
|
|
let val chrExists = chrExistsInVec (0, chars, curChr)
|
|
in {sawConcat = false, follows = [], charIsMatch = chrExists}
|
|
end
|
|
| NOT_ANY_CHARACTER {chars, ...} =>
|
|
let
|
|
val charIsValid = chrExistsInVec (0, chars, curChr)
|
|
val charIsValid =
|
|
not charIsValid andalso Fn.charIsNotEqual (curChr, Fn.endMarker)
|
|
in
|
|
{sawConcat = false, follows = [], charIsMatch = charIsValid}
|
|
end
|
|
| ALTERNATION {l, r, leftMaxState, rightMaxState} =>
|
|
let val nodeToFollow = if pos <= leftMaxState then l else r
|
|
in getFollowsForPositionAndChar (nodeToFollow, pos, curChr)
|
|
end
|
|
| GROUP regex => getFollowsForPositionAndChar (regex, pos, curChr)
|
|
|
|
| CONCAT {l, r, leftMaxState, ...} =>
|
|
if pos <= leftMaxState then
|
|
let
|
|
val result = getFollowsForPositionAndChar (l, pos, curChr)
|
|
val {sawConcat, follows, charIsMatch} = result
|
|
in
|
|
if charIsMatch then
|
|
if sawConcat then
|
|
(* we already saw a concat and got followpos *)
|
|
result
|
|
else
|
|
let val fp = followpos (curChr, regex, follows)
|
|
in {sawConcat = true, follows = fp, charIsMatch = true}
|
|
end
|
|
else
|
|
(* char is not match, so don't get follow pos *)
|
|
result
|
|
end
|
|
else
|
|
getFollowsForPositionAndChar (r, pos, curChr)
|
|
| ZERO_OR_MORE child =>
|
|
let
|
|
val result = getFollowsForPositionAndChar (child, pos, curChr)
|
|
val {sawConcat, follows, charIsMatch} = result
|
|
in
|
|
if charIsMatch then
|
|
{ sawConcat = false
|
|
, follows = firstpos (child, follows)
|
|
, charIsMatch = true
|
|
}
|
|
else
|
|
result
|
|
end
|
|
| ZERO_OR_ONE child => getFollowsForPositionAndChar (child, pos, curChr)
|
|
| ONE_OR_MORE child =>
|
|
let
|
|
val result = getFollowsForPositionAndChar (child, pos, curChr)
|
|
val {sawConcat, follows, charIsMatch} = result
|
|
in
|
|
if charIsMatch then
|
|
{ sawConcat = false
|
|
, follows = firstpos (child, follows)
|
|
, charIsMatch = true
|
|
}
|
|
else
|
|
result
|
|
end
|
|
|
|
fun getFollowPositionsFromList (lst: int list, regex, char, followSet) =
|
|
case lst of
|
|
hd :: tl =>
|
|
let
|
|
val fpList = getFollowsForPositionAndChar (regex, hd, char)
|
|
val {sawConcat, follows, charIsMatch} = fpList
|
|
val follows =
|
|
if charIsMatch andalso not sawConcat then
|
|
(Char.ord Fn.endMarker) :: follows
|
|
else
|
|
follows
|
|
|
|
val followSet =
|
|
List.foldl
|
|
(fn (fp, followSet) => Set.insertOrReplace (fp, (), followSet))
|
|
followSet follows
|
|
in
|
|
getFollowPositionsFromList (tl, regex, char, followSet)
|
|
end
|
|
| [] => Set.keysToList followSet
|
|
|
|
fun appendIfNew (pos, dstates, newStates) =
|
|
if pos = Vector.length dstates then
|
|
let
|
|
val record = {transitions = newStates, marked = false}
|
|
val dstates = Vector.concat [dstates, Vector.fromList [record]]
|
|
in
|
|
(pos, dstates)
|
|
end
|
|
else
|
|
let
|
|
val {transitions: int list, marked = _} = Vector.sub (dstates, pos)
|
|
in
|
|
if transitions = newStates then (pos, dstates)
|
|
else appendIfNew (pos + 1, dstates, newStates)
|
|
end
|
|
|
|
fun getUnmarkedTransitionsIfExists (pos, dstates) =
|
|
if pos = Vector.length dstates then
|
|
NONE
|
|
else
|
|
let
|
|
val record = Vector.sub (dstates, pos)
|
|
in
|
|
if #marked record then
|
|
getUnmarkedTransitionsIfExists (pos + 1, dstates)
|
|
else
|
|
SOME (pos, #transitions record)
|
|
end
|
|
|
|
(* the int key in dtran refers to the char code
|
|
* while the int value refers to the idx from dstates
|
|
* that this char transitions to *)
|
|
type dtran = int Set.set
|
|
|
|
fun makeEmptyVec _ = ~1
|
|
|
|
fun convertChar
|
|
( char
|
|
, regex
|
|
, dstates
|
|
, dtran: dtran vector
|
|
, curStates
|
|
, curStatesIdx
|
|
, setForCurStates
|
|
) =
|
|
if char < 0 then
|
|
let
|
|
(* append setForCurStates which was accumulated in this function
|
|
* to the end of dtran. *)
|
|
val dtran = Vector.concat [dtran, Vector.fromList [setForCurStates]]
|
|
in
|
|
(dstates, dtran)
|
|
end
|
|
else
|
|
let
|
|
(* get union of all follow positions *)
|
|
val u =
|
|
getFollowPositionsFromList
|
|
(curStates, regex, Char.chr char, Set.LEAF)
|
|
in
|
|
case u of
|
|
[] =>
|
|
(* no follow positions from here, so don't add to dstates *)
|
|
convertChar
|
|
( char - 1
|
|
, regex
|
|
, dstates
|
|
, dtran
|
|
, curStates
|
|
, curStatesIdx
|
|
, setForCurStates
|
|
)
|
|
| _ =>
|
|
let
|
|
(* add follow positions to dstates if they are not already inside
|
|
* and if follow is not empty *)
|
|
val (newStateIdx, dstates) = appendIfNew (0, dstates, u)
|
|
|
|
(* update dtran to include transitions for char. *)
|
|
val setForCurStates =
|
|
Set.insertOrReplace (char, newStateIdx, setForCurStates)
|
|
in
|
|
convertChar
|
|
( char - 1
|
|
, regex
|
|
, dstates
|
|
, dtran
|
|
, curStates
|
|
, curStatesIdx
|
|
, setForCurStates
|
|
)
|
|
end
|
|
end
|
|
|
|
fun convertLoop (regex, dstates, dtran) =
|
|
case getUnmarkedTransitionsIfExists (0, dstates) of
|
|
SOME (unmarkedIdx, unamarkedTransition) =>
|
|
let
|
|
(* mark transition *)
|
|
val dstates =
|
|
let
|
|
val newMark = {marked = true, transitions = unamarkedTransition}
|
|
in
|
|
Vector.update (dstates, unmarkedIdx, newMark)
|
|
end
|
|
|
|
val (dstates, dtran) = convertChar
|
|
( 255
|
|
, regex
|
|
, dstates
|
|
, dtran
|
|
, unamarkedTransition
|
|
, unmarkedIdx
|
|
, Set.LEAF
|
|
)
|
|
in
|
|
convertLoop (regex, dstates, dtran)
|
|
end
|
|
| NONE =>
|
|
Vector.map
|
|
(fn set =>
|
|
Vector.tabulate (256, fn i => Set.getOrDefault (i, set, ~1)))
|
|
dtran
|
|
|
|
fun convert regex =
|
|
let
|
|
val first = List.rev (firstpos (regex, []))
|
|
val dstates = Vector.fromList [{transitions = first, marked = false}]
|
|
in
|
|
convertLoop (regex, dstates, Vector.fromList [])
|
|
end
|
|
end
|
|
|
|
fun fromString str =
|
|
case ParseDfa.parse (str, 0) of
|
|
SOME (ast, numStates) =>
|
|
let
|
|
val endMarker =
|
|
CHAR_LITERAL {char = Fn.endMarker, position = numStates + 1}
|
|
val ast = CONCAT
|
|
{ l = ast
|
|
, leftMaxState = numStates
|
|
, r = endMarker
|
|
, rightMaxState = numStates + 1
|
|
}
|
|
in
|
|
ToDfa.convert ast
|
|
end
|
|
| NONE => Vector.fromList []
|
|
|
|
type dfa = int vector vector
|
|
type dfa_state = int
|
|
|
|
fun nextState (dfa: dfa, curState: dfa_state, chr) =
|
|
let val curTable = Vector.sub (dfa, curState)
|
|
in Vector.sub (curTable, Char.ord chr)
|
|
end
|
|
|
|
fun isFinal (dfa: dfa, curState: dfa_state) =
|
|
curState <> ~1
|
|
andalso
|
|
let
|
|
val curTable = Vector.sub (dfa, curState)
|
|
val endMarkerCode = Char.ord Fn.endMarker
|
|
in
|
|
Vector.sub (curTable, endMarkerCode) <> ~1
|
|
end
|
|
|
|
fun isDead (curState: dfa_state) = curState = ~1
|
|
|
|
fun helpMatchString (strPos, str, dfa, curState, startPos, prevFinalPos, acc) =
|
|
if strPos = String.size str then
|
|
let
|
|
val acc =
|
|
if prevFinalPos = ~1 then acc else (startPos, prevFinalPos) :: acc
|
|
in
|
|
List.rev acc
|
|
end
|
|
else
|
|
let
|
|
val chr = String.sub (str, strPos)
|
|
val newState = nextState (dfa, curState, chr)
|
|
val prevFinalPos =
|
|
if isFinal (dfa, newState) then strPos else prevFinalPos
|
|
in
|
|
if isDead newState then
|
|
if prevFinalPos = ~1 then
|
|
(* restart from startPos *)
|
|
helpMatchString (startPos + 1, str, dfa, 0, startPos + 1, ~1, acc)
|
|
else
|
|
let
|
|
val acc = (startPos, prevFinalPos) :: acc
|
|
in
|
|
helpMatchString
|
|
(prevFinalPos + 1, str, dfa, 0, prevFinalPos + 1, ~1, acc)
|
|
end
|
|
else
|
|
helpMatchString
|
|
(strPos + 1, str, dfa, newState, startPos, prevFinalPos, acc)
|
|
end
|
|
|
|
fun matchString (dfa, string) =
|
|
if Vector.length dfa = 0 then []
|
|
else helpMatchString (0, string, dfa, 0, 0, ~1, [])
|
|
end
|
|
|
|
structure CaseInsensitiveDfa =
|
|
MakeDfaGen
|
|
(struct
|
|
val endMarker = #"\^@"
|
|
fun charIsEqual (a: char, b: char) = Char.toLower a = Char.toLower b
|
|
fun charIsNotEqual (a: char, b: char) = a <> b
|
|
end)
|
|
|
|
structure CaseSensitiveDfa =
|
|
MakeDfaGen
|
|
(struct
|
|
val endMarker = #"\^@"
|
|
fun charIsEqual (a: char, b: char) = a = b
|
|
fun charIsNotEqual (a: char, b: char) = a <> b
|
|
end)
|