implement "a like b" operator (and alias "a matches b"). pattern matching code taken from NetBSD src/lib/libc/gen/fnmatch.c

parser_native/parser.cpp

@@ -85,6 +85,8 @@ struct parser_closure : boost::spirit::closure<parser_closure, datum>
 
 namespace {
 
+int match(char const *, char const *);
+
 datum
 f_in(datum const &a, datum const &b)
 {
@@ -92,6 +94,12 @@ f_in(datum const &a, datum const &b)
 	return datum(std::search(sb.begin(), sb.end(), sa.begin(), sa.end()) != sb.end());
 }
 
+datum
+f_like(datum const &str, datum const &pattern)
+{
+	return datum::from_int(match(str.toString().c_str(), pattern.toString().c_str()));
+}
+
 datum
 f_ternary(datum const &v, datum const &iftrue, datum const &iffalse)
 {
@@ -280,6 +288,8 @@ struct parser_grammar : public grammar<parser_grammar, parser_closure::context_t
 				>> *(
 					  "in"       >> basic[in_expr.val = bind(&f_in)(in_expr.val, arg1)]
 					| "contains" >> basic[in_expr.val = bind(&f_in)(arg1, in_expr.val)]
+					| "like"     >> basic[in_expr.val = bind(&f_like)(arg1, in_expr.val)]
+					| "matches"     >> basic[in_expr.val = bind(&f_like)(arg1, in_expr.val)]
 				    )
 				;
 
@@ -448,6 +458,148 @@ expressor::add_function(std::string const &name, func_t value)
 	grammar_->add_function(name, value);
 }
 
+namespace {
+
+/*	$NetBSD: fnmatch.c,v 1.21 2005/12/24 21:11:16 perry Exp $	*/
+
+/*
+ * Copyright (c) 1989, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Guido van Rossum.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * Function fnmatch() as specified in POSIX 1003.2-1992, section B.6.
+ * Compares a filename or pathname to a pattern.
+ */
+
+#include <ctype.h>
+#include <string.h>
+
+#define	EOS	'\0'
+
+const char *rangematch (const char *, int);
+
+int
+match(char const *pattern, char const *string)
+{
+	const char *stringstart;
+	char c, test;
+
+	for (stringstart = string;;)
+		switch (c = *pattern++) {
+		case EOS:
+			return (*string == EOS ? 1 : 0);
+		case '?':
+			if (*string == EOS)
+				return (0);
+			++string;
+			break;
+		case '*':
+			c = *pattern;
+			/* Collapse multiple stars. */
+			while (c == '*')
+				c = *++pattern;
+
+			/* Optimize for pattern with * at end or before /. */
+			if (c == EOS) {
+				return (1);
+			}
+
+			/* General case, use recursion. */
+			while ((test = *string) != EOS) {
+				if (match(pattern, string))
+					return (1);
+				++string;
+			}
+			return (0);
+		case '[':
+			if (*string == EOS)
+				return (0);
+			if ((pattern =
+			    rangematch(pattern, *string)) == NULL)
+				return (0);
+			++string;
+			break;
+		case '\\':
+			if ((c = *pattern++) == EOS) {
+				c = '\\';
+				--pattern;
+			}
+			/* FALLTHROUGH */
+		default:
+			if (c != *string++)
+				return (0);
+			break;
+		}
+	/* NOTREACHED */
+}
+
+const char *
+rangematch(char const *pattern, int test)
+{
+	int negate, ok;
+	char c, c2;
+
+	/*
+	 * A bracket expression starting with an unquoted circumflex
+	 * character produces unspecified results (IEEE 1003.2-1992,
+	 * 3.13.2).  This implementation treats it like '!', for
+	 * consistency with the regular expression syntax.
+	 * J.T. Conklin (conklin@ngai.kaleida.com)
+	 */
+	if ((negate = (*pattern == '!' || *pattern == '^')) != 0)
+		++pattern;
+	
+	for (ok = 0; (c = *pattern++) != ']';) {
+		if (c == '\\')
+			c = *pattern++;
+		if (c == EOS)
+			return (NULL);
+		if (*pattern == '-' 
+		    && (c2 = (*(pattern+1))) != EOS &&
+		        c2 != ']') {
+			pattern += 2;
+			if (c2 == '\\')
+				c2 = *pattern++;
+			if (c2 == EOS)
+				return (NULL);
+			if (c <= test && test <= c2)
+				ok = 1;
+		} else if (c == test)
+			ok = 1;
+	}
+	return (ok == negate ? NULL : pattern);
+}
+
+} // anonymous namespace
+
 } // namespace afp
 
 #ifdef TEST_PARSER