TextUtils.m3
Some useful text processing routines for the PL1 compiler.
Copyright (c) 2000 California Institute of Technology
All rights reserved.
Department of Computer Science
Pasadena, CA 91125.
Author: Mika Nystrom <mika@cs.caltech.edu>
Permission to use, copy, modify, and distribute this software
and its documentation for any purpose and without fee is hereby
granted, provided that the above copyright notice appear in all
copies. The California Institute of Technology makes no representations
about the suitability of this software for any purpose. It is
provided as is without express or implied warranty. Export of this
software outside of the United States of America may require an
export license.
$Id: TextUtils.m3.html,v 1.3 2010-04-29 17:17:56 wagner Exp $
MODULE TextUtils;
IMPORT Text;
IMPORT Fmt;
IMPORT TextSet, TextSetDef, TextList;
PROCEDURE CountCharOccurences(in: TEXT; c: CHAR): CARDINAL =
VAR
count := 0;
BEGIN
FOR i := 0 TO Text.Length(in) - 1 DO
IF Text.GetChar(in,i) = c THEN
INC(count);
END;
END;
RETURN count;
END CountCharOccurences;
PROCEDURE ReplaceChar(in : TEXT; old, new : CHAR) : TEXT =
VAR
res := NEW(REF ARRAY OF CHAR, Text.Length(in));
BEGIN
FOR i := 0 TO Text.Length(in) - 1 DO
WITH char = Text.GetChar(in,i) DO
IF char = old THEN res[i] := new ELSE res[i] := char END
END
END;
RETURN Text.FromChars(res^)
END ReplaceChar;
PROCEDURE Replace(in, old, new : TEXT) : TEXT =
VAR
startpos := 0;
nextpos : CARDINAL;
BEGIN
WHILE FindSub(in, old, nextpos, startpos) DO
in := Text.Sub(in, 0, nextpos) & new &
Text.Sub(in, nextpos + Text.Length(old));
startpos := nextpos + Text.Length(old) - Text.Length(new)
END;
RETURN in
END Replace;
find first occurrence of sub in in
PROCEDURE FindSub(in, sub : TEXT; VAR pos : CARDINAL; start := 0) : BOOLEAN =
VAR
inA := NEW(REF ARRAY OF CHAR, Text.Length(in));
subA := NEW(REF ARRAY OF CHAR, Text.Length(sub));
BEGIN
Text.SetChars(inA^,in);
Text.SetChars(subA^,sub);
FOR i := start TO LAST(inA^) - LAST(subA^) DO
VAR
success := TRUE;
BEGIN
FOR j := 0 TO LAST(subA^) DO
IF subA[j] # inA[i + j] THEN
success := FALSE;
EXIT
END
END;
IF success THEN pos := i; RETURN TRUE END
END
END;
RETURN FALSE
END FindSub;
PROCEDURE HaveSub(in, sub : TEXT) : BOOLEAN =
VAR x : CARDINAL; BEGIN RETURN FindSub(in, sub, x) END HaveSub;
PROCEDURE HavePrefix(in, prefix: TEXT): BOOLEAN =
BEGIN
RETURN Text.Equal(Text.Sub(in, 0, Text.Length(prefix)), prefix);
END HavePrefix;
PROCEDURE HaveSuffix(in, suffix: TEXT): BOOLEAN =
VAR
pos := Text.Length(in) - Text.Length(suffix);
BEGIN
RETURN pos >= 0 AND Text.Equal(Text.Sub(in, pos), suffix);
END HaveSuffix;
PROCEDURE RemoveSuffix(in, suffix: TEXT): TEXT =
VAR
pos := Text.Length(in) - Text.Length(suffix);
BEGIN
<* ASSERT pos >= 0 AND Text.Equal(Text.Sub(in, pos), suffix) *>
RETURN Text.Sub(in, 0, pos);
END RemoveSuffix;
PROCEDURE Pluralize(noun : TEXT; n : INTEGER;
ending : TEXT; printNum : BOOLEAN) : TEXT =
VAR
res : TEXT;
BEGIN
IF printNum THEN res := Fmt.Int(n) & " " ELSE res := "" END;
IF n = 1 THEN RETURN res & noun ELSE RETURN res & noun & ending END
END Pluralize;
PROCEDURE ListToSet(l : TextList.T) : TextSet.T =
VAR
res := NEW(TextSetDef.T).init();
BEGIN
WHILE l # NIL DO EVAL res.insert(l.head); l := l.tail END;
RETURN res
END ListToSet;
PROCEDURE SetToList(set : TextSet.T) : TextList.T =
VAR
iter := set.iterate();
t : TEXT;
res : TextList.T := NIL;
BEGIN
WHILE iter.next(t) DO res := TextList.Cons(t,res) END;
RETURN res
END SetToList;
BEGIN END TextUtils.