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<H1><A NAME="SEC695" HREF="ciao_toc.html#TOC695">Pattern (regular expression) matching</A></H1>
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<STRONG>Author(s):</STRONG> The CLIP Group.
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<STRONG>Version:</STRONG> 1.10#7 (2006/4/26, 19:22:13 CEST)
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<STRONG>Version of last change:</STRONG> 1.9#255 (2003/12/30, 23:32:38 CET)
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This library provides facilities for matching strings and terms against
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<EM>patterns</EM> (i.e.,
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<EM>regular expressions</EM>).
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<LI><A HREF="ciao_168.html#SEC696">Usage and interface (patterns)</A>
<LI><A HREF="ciao_168.html#SEC697">Documentation on exports (patterns)</A>
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<H2><A NAME="SEC696" HREF="ciao_toc.html#TOC696">Usage and interface (<CODE>patterns</CODE>)</A></H2>
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<LI><STRONG>Library usage:</STRONG>
<CODE>:- use_module(library(patterns)).</CODE>
<LI><STRONG>Exports:</STRONG>
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<LI><EM>Predicates:</EM>
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<CODE>match_pattern/2</CODE>,
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<CODE>match_pattern/3</CODE>,
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<CODE>case_insensitive_match/2</CODE>,
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<CODE>letter_match/2</CODE>,
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<CODE>match_pattern_pred/2</CODE>.
<LI><EM>Regular Types:</EM>
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<CODE>pattern/1</CODE>.
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<LI><STRONG>Other modules used:</STRONG>
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<LI><EM>System library modules:</EM>
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<CODE>lists</CODE>.
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<H2><A NAME="SEC697" HREF="ciao_toc.html#TOC697">Documentation on exports (<CODE>patterns</CODE>)</A></H2>
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<DT><span class="define">PREDICATE:</span> <B>match_pattern/2:</B>
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<STRONG>Usage:</STRONG> <CODE>match_pattern(Pattern, String)</CODE>
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<LI><EM>Description:</EM> Matches <CODE>String</CODE> against <CODE>Pattern</CODE>. For example, <CODE>match_pattern("*.pl","foo.pl")</CODE> succeeds.
<LI><EM>The following properties should hold at call time:</EM>
<CODE>Pattern</CODE> is a pattern to match against.
(<CODE>patterns:pattern/1</CODE>)
<CODE>String</CODE> is a string (a list of character codes).
(<CODE>basic_props:string/1</CODE>)
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<DT><span class="define">PREDICATE:</span> <B>match_pattern/3:</B>
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<STRONG>Usage:</STRONG> <CODE>match_pattern(Pattern, String, Tail)</CODE>
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<LI><EM>Description:</EM> Matches <CODE>String</CODE> against <CODE>Pattern</CODE>. <CODE>Tail</CODE> is the remainder of the string after the match. For example, <CODE>match_pattern("??*","foo.pl",Tail)</CODE> succeeds, instantiating <CODE>Tail</CODE> to <CODE>"o.pl"</CODE>.
<LI><EM>The following properties should hold at call time:</EM>
<CODE>Pattern</CODE> is a pattern to match against.
(<CODE>patterns:pattern/1</CODE>)
<CODE>String</CODE> is a string (a list of character codes).
(<CODE>basic_props:string/1</CODE>)
<CODE>Tail</CODE> is a string (a list of character codes).
(<CODE>basic_props:string/1</CODE>)
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<DT><span class="define">PREDICATE:</span> <B>case_insensitive_match/2:</B>
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<STRONG>Usage:</STRONG> <CODE>case_insensitive_match(Pred1, Pred2)</CODE>
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<LI><EM>Description:</EM> Tests if two predicates <CODE>Pred1</CODE> and <CODE>Pred2</CODE> match in a case-insensitive way.
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<DT><span class="define">PREDICATE:</span> <B>letter_match/2:</B>
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<STRONG>Usage:</STRONG> <CODE>letter_match(X, Y)</CODE>
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<LI><EM>Description:</EM> True iff <CODE>X</CODE> and <CODE>Y</CODE> represents the same letter
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<DT><span class="define">REGTYPE:</span> <B>pattern/1:</B>
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Special characters for <CODE>Pattern</CODE> are:
<DL COMPACT>
<DT>*
<DD>
Matches any string, including the null string.
<DT>?
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Matches any single character.
<DT>[...]
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Matches any one of the enclosed characters. A pair of characters separated by a minus sign denotes a range; any character lexically between those two characters, inclusive, is matched. If the first character following the [ is a ^ then any character not enclosed is matched. No other character is special inside this construct. To include a ] in a character set, you must make it the first character. To include a `-', you must use it in a context where it cannot possibly indicate a range: that is, as the first character, or immediately after a range.
<DT>|
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Specifies an alternative. Two patterns A and B with | in between form an expression that matches anything that either A or B will match.
<DT>{...}
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Groups alternatives inside larger patterns.
<DT>\
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Quotes a special character (including itself).
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<STRONG>Usage:</STRONG> <CODE>pattern(P)</CODE>
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<LI><EM>Description:</EM> <CODE>P</CODE> is a pattern to match against.
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<DT><span class="define">PREDICATE:</span> <B>match_pattern_pred/2:</B>
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<STRONG>Usage:</STRONG> <CODE>match_pattern_pred(Pred1, Pred2)</CODE>
<UL>
<LI><EM>Description:</EM> Tests if two predicates <CODE>Pred1</CODE> and <CODE>Pred2</CODE> match using regular expressions.
</UL>
</DL>
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