Implement SQL99 OVERLAY(). Allows substitution of a substring in a string.

Implement SQL99 SIMILAR TO as a synonym for our existing operator "~".
Implement SQL99 regular expression SUBSTRING(string FROM pat FOR escape).
 Extend the definition to make the FOR clause optional.
 Define textregexsubstr() to actually implement this feature.
Update the regression test to include these new string features.
 All tests pass.
Rename the regular expression support routines from "pg95_xxx" to "pg_xxx".
Define CREATE CHARACTER SET in the parser per SQL99. No implementation yet.

doc/src/sgml/ref/set.sgml

 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/set.sgml,v 1.61 2002/05/18 15:44:47 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/set.sgml,v 1.62 2002/06/11 15:41:30 thomas Exp $
 PostgreSQL documentation
 -->
 
@@ -112,7 +112,6 @@ SET [ SESSION | LOCAL ] TIME ZONE { <replaceable class="PARAMETER">timezone</rep
    Here are additional details about a few of the parameters that can be set:
 
    <variablelist>
-
     <varlistentry>
      <term>DATESTYLE</term>
      <listitem>
@@ -220,7 +219,7 @@ SET [ SESSION | LOCAL ] TIME ZONE { <replaceable class="PARAMETER">timezone</rep
         </member>
         <member>
          Running postmaster using the option <option>-o -e</option> to
-	 select the <literal>European</literal> conventions.
+         set dates to the <literal>European</literal> convention.
          (This overrides environment variables and configuration-file
          entries.)
         </member>
@@ -229,7 +228,7 @@ SET [ SESSION | LOCAL ] TIME ZONE { <replaceable class="PARAMETER">timezone</rep
          If PGDATESTYLE is set in the frontend environment of a client
          based on libpq, libpq will automatically set DATESTYLE to the
          value of PGDATESTYLE during connection start-up.  This is
-	 equivalent to a manually issued <command>SET</>.
+         equivalent to a manually issued <command>SET DATESTYLE</>.
         </member>
        </simplelist>
       </para>
@@ -275,7 +274,6 @@ SET [ SESSION | LOCAL ] TIME ZONE { <replaceable class="PARAMETER">timezone</rep
 SELECT setseed(<replaceable>value</replaceable>);
        </programlisting>
       </para>
-
      </listitem>
     </varlistentry>
 
@@ -302,20 +300,14 @@ SELECT setseed(<replaceable>value</replaceable>);
       </para>
 
       <para>
-	The available time zone names depend on your operating
-	system. For example, on Linux
-	<filename>/usr/share/zoneinfo</filename> contains the database
-	of time zones.
-       </para>
-       <para>
-	Here are some typical values for time zone names:
+       Here are some typical values for time zone settings:
 
        <variablelist>
         <varlistentry>
          <term>'PST8PDT'</term>
          <listitem>
           <para>
-	    Set the time zone for California.
+           Set the time zone for Berkeley, California.
           </para>
          </listitem>
         </varlistentry>
@@ -335,14 +327,6 @@ SELECT setseed(<replaceable>value</replaceable>);
           </para>
          </listitem>
         </varlistentry>
-	</variablelist>
-       </para>
-
-       <para>
-	In addition to time zone names, <productname>PostgreSQL</productname>
-	accepts these other methods of specifying a time zone:
-
-       <variablelist>
         <varlistentry>
          <term>7</term>
          <listitem>
@@ -373,18 +357,28 @@ SELECT setseed(<replaceable>value</replaceable>);
         </varlistentry>
        </variablelist>
       </para>
+
       <para>
-	If an invalid time zone name is specified, the time zone
+       The available time zone names depend on your operating
+       system. For example, on Linux
+       <filename>/usr/share/zoneinfo</filename> contains the database
+       of time zones; the names of the files in that directory can be
+       used as parameters to this command.
+      </para>
+
+      <para>
+       If an invalid time zone is specified, the time zone
        becomes GMT (on most systems anyway).
       </para>
+
       <para>
        If the <envar>PGTZ</envar> environment variable is set in the frontend
        environment of a client based on libpq, libpq will automatically
-	set TIMEZONE to the value of <envar>PGTZ</envar> during connection start-up.
+       <command>SET TIMEZONE</command> to the value of
+       <envar>PGTZ</envar> during connection start-up. 
       </para>
      </listitem>
     </varlistentry>
-
    </variablelist>
   </para>
 

src/backend/parser/gram.y

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.320 2002/06/11 13:40:50 wieck Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.321 2002/06/11 15:41:37 thomas Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -227,10 +227,10 @@ static void doNegateFloat(Value *v);
 %type <node>	join_outer, join_qual
 %type <jtype>	join_type
 
-%type <list>	extract_list, position_list
+%type <list>	extract_list, overlay_list, position_list
 %type <list>	substr_list, trim_list
 %type <ival>	opt_interval
-%type <node>	substr_from, substr_for
+%type <node>	overlay_placing, substr_from, substr_for
 
 %type <boolean>	opt_binary, opt_using, opt_instead, opt_cursor
 %type <boolean>	opt_with_copy, index_opt_unique, opt_verbose, opt_full
@@ -336,7 +336,7 @@ static void doNegateFloat(Value *v);
 	FALSE_P, FETCH, FLOAT_P, FOR, FORCE, FOREIGN, FORWARD, FREEZE, FROM,
 	FULL, FUNCTION,
 
-	GLOBAL, GRANT, GROUP_P,
+	GET, GLOBAL, GRANT, GROUP_P,
 	HANDLER, HAVING, HOUR_P,
 
 	ILIKE, IMMEDIATE, IMMUTABLE, IMPLICIT, IN_P, INCREMENT, INDEX, INHERITS,
@@ -356,16 +356,16 @@ static void doNegateFloat(Value *v);
 	NUMERIC,
 
 	OF, OFF, OFFSET, OIDS, OLD, ON, ONLY, OPERATOR, OPTION, OR, ORDER,
-	OUT_P, OUTER_P, OVERLAPS, OWNER,
+	OUT_P, OUTER_P, OVERLAPS, OVERLAY, OWNER,
 
-	PARTIAL, PASSWORD, PATH_P, PENDANT, POSITION, PRECISION, PRIMARY,
+	PARTIAL, PASSWORD, PATH_P, PENDANT, PLACING, POSITION, PRECISION, PRIMARY,
 	PRIOR, PRIVILEGES, PROCEDURE, PROCEDURAL,
 
 	READ, REAL, REFERENCES, REINDEX, RELATIVE, RENAME, REPLACE, RESET,
 	RESTRICT, RETURNS, REVOKE, RIGHT, ROLLBACK, ROW, RULE,
 
 	SCHEMA, SCROLL, SECOND_P, SECURITY, SELECT, SEQUENCE, SERIALIZABLE,
-	SESSION, SESSION_USER, SET, SETOF, SHARE, SHOW, SMALLINT, SOME,
+	SESSION, SESSION_USER, SET, SETOF, SHARE, SHOW, SIMILAR, SMALLINT, SOME,
 	STABLE, START, STATEMENT, STATISTICS, STDIN, STDOUT, STORAGE, STRICT,
 	SUBSTRING, SYSID,
 
@@ -402,7 +402,7 @@ static void doNegateFloat(Value *v);
 %right		NOT
 %right		'='
 %nonassoc	'<' '>'
-%nonassoc	LIKE ILIKE
+%nonassoc	LIKE ILIKE SIMILAR
 %nonassoc	ESCAPE
 %nonassoc	OVERLAPS
 %nonassoc	BETWEEN
@@ -420,6 +420,7 @@ static void doNegateFloat(Value *v);
 %right		UMINUS
 %left		'[' ']'
 %left		'(' ')'
+%left		COLLATE
 %left		TYPECAST
 %left		'.'
 %%
@@ -2139,6 +2140,14 @@ DefineStmt:  CREATE AGGREGATE func_name definition
 					n->definition = $4;
 					$$ = (Node *)n;
 				}
+		| CREATE CHARACTER SET opt_as any_name GET definition opt_collate
+				{
+					DefineStmt *n = makeNode(DefineStmt);
+					n->defType = CHARACTER;
+					n->defnames = $5;
+					n->definition = $7;
+					$$ = (Node *)n;
+				}
 		;
 
 definition:  '(' def_list ')'				{ $$ = $2; }
@@ -4981,6 +4990,15 @@ a_expr:  c_expr
 				{	$$ = $1; }
 		| a_expr TYPECAST Typename
 				{	$$ = makeTypeCast($1, $3); }
+		| a_expr COLLATE ColId
+				{
+					FuncCall *n = makeNode(FuncCall);
+					n->funcname = SystemFuncName($3);
+					n->args = makeList1($1);
+					n->agg_star = FALSE;
+					n->agg_distinct = FALSE;
+					$$ = (Node *) n;
+				}
 		| a_expr AT TIME ZONE c_expr
 				{
 					FuncCall *n = makeNode(FuncCall);
@@ -5088,6 +5106,30 @@ a_expr:  c_expr
 					n->agg_distinct = FALSE;
 					$$ = (Node *) makeSimpleA_Expr(OP, "!~~*", $1, (Node *) n);
 				}
+
+		| a_expr SIMILAR TO a_expr				%prec SIMILAR
+				{	$$ = (Node *) makeSimpleA_Expr(OP, "~", $1, $4); }
+		| a_expr SIMILAR TO a_expr ESCAPE a_expr
+				{
+					FuncCall *n = makeNode(FuncCall);
+					n->funcname = SystemFuncName("like_escape");
+					n->args = makeList2($4, $6);
+					n->agg_star = FALSE;
+					n->agg_distinct = FALSE;
+					$$ = (Node *) makeSimpleA_Expr(OP, "~", $1, (Node *) n);
+				}
+		| a_expr NOT SIMILAR TO a_expr			%prec SIMILAR
+				{	$$ = (Node *) makeSimpleA_Expr(OP, "!~", $1, $5); }
+		| a_expr NOT SIMILAR TO a_expr ESCAPE a_expr
+				{
+					FuncCall *n = makeNode(FuncCall);
+					n->funcname = SystemFuncName("like_escape");
+					n->args = makeList2($5, $7);
+					n->agg_star = FALSE;
+					n->agg_distinct = FALSE;
+					$$ = (Node *) makeSimpleA_Expr(OP, "!~", $1, (Node *) n);
+				}
+
 		/* NullTest clause
 		 * Define SQL92-style Null test clause.
 		 * Allow two forms described in the standard:
@@ -5568,6 +5610,20 @@ c_expr:  columnref
 					n->agg_distinct = FALSE;
 					$$ = (Node *)n;
 				}
+		| OVERLAY '(' overlay_list ')'
+				{
+					/* overlay(A PLACING B FROM C FOR D) is converted to
+					 * substring(A, 1, C-1) || B || substring(A, C+1, C+D)
+					 * overlay(A PLACING B FROM C) is converted to
+					 * substring(A, 1, C-1) || B || substring(A, C+1, C+char_length(B))
+					 */
+					FuncCall *n = makeNode(FuncCall);
+					n->funcname = SystemFuncName("overlay");
+					n->args = $3;
+					n->agg_star = FALSE;
+					n->agg_distinct = FALSE;
+					$$ = (Node *)n;
+				}
 		| POSITION '(' position_list ')'
 				{
 					/* position(A in B) is converted to position(B, A) */
@@ -5706,6 +5762,25 @@ extract_arg:  IDENT						{ $$ = $1; }
 		| SCONST						{ $$ = $1; }
 		;
 
+/* OVERLAY() arguments
+ * SQL99 defines the OVERLAY() function:
+ * o overlay(text placing text from int for int)
+ * o overlay(text placing text from int)
+ */
+overlay_list:  a_expr overlay_placing substr_from substr_for
+				{
+					$$ = makeList4($1, $2, $3, $4);
+				}
+		| a_expr overlay_placing substr_from
+				{
+					$$ = makeList3($1, $2, $3);
+				}
+		;
+
+overlay_placing:  PLACING a_expr
+				{	$$ = $2; }
+		;
+
 /* position_list uses b_expr not a_expr to avoid conflict with general IN */
 
 position_list:  b_expr IN_P b_expr
@@ -6259,6 +6334,7 @@ unreserved_keyword:
 		| FORCE
 		| FORWARD
 		| FUNCTION
+		| GET
 		| GLOBAL
 		| HANDLER
 		| HOUR_P
@@ -6404,6 +6480,7 @@ col_name_keyword:
 		| NONE
 		| NULLIF
 		| NUMERIC
+		| OVERLAY
 		| POSITION
 		| REAL
 		| SETOF
@@ -6445,6 +6522,7 @@ func_name_keyword:
 		| OUTER_P
 		| OVERLAPS
 		| RIGHT
+		| SIMILAR
 		| VERBOSE
 		;
 

src/backend/parser/keywords.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/keywords.c,v 1.112 2002/06/11 13:40:51 wieck Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/keywords.c,v 1.113 2002/06/11 15:41:37 thomas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -129,6 +129,7 @@ static const ScanKeyword ScanKeywords[] = {
 	{"from", FROM},
 	{"full", FULL},
 	{"function", FUNCTION},
+	{"get", GET},
 	{"global", GLOBAL},
 	{"grant", GRANT},
 	{"group", GROUP_P},
@@ -211,11 +212,13 @@ static const ScanKeyword ScanKeywords[] = {
 	{"out", OUT_P},
 	{"outer", OUTER_P},
 	{"overlaps", OVERLAPS},
+	{"overlay", OVERLAY},
 	{"owner", OWNER},
 	{"partial", PARTIAL},
 	{"password", PASSWORD},
 	{"path", PATH_P},
 	{"pendant", PENDANT},
+	{"placing", PLACING},
 	{"position", POSITION},
 	{"precision", PRECISION},
 	{"primary", PRIMARY},
@@ -251,6 +254,7 @@ static const ScanKeyword ScanKeywords[] = {
 	{"setof", SETOF},
 	{"share", SHARE},
 	{"show", SHOW},
+	{"similar", SIMILAR},
 	{"smallint", SMALLINT},
 	{"some", SOME},
 	{"stable", STABLE},

src/backend/parser/scan.l

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/scan.l,v 1.94 2002/05/02 18:44:10 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/scan.l,v 1.95 2002/06/11 15:41:37 thomas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -92,14 +92,14 @@ unsigned char unescape_single_char(unsigned char c);
  * We use exclusive states for quoted strings, extended comments,
  * and to eliminate parsing troubles for numeric strings.
  * Exclusive states:
- *  <xbit> bit string literal
+ *  <xb> bit string literal
  *  <xc> extended C-style comments - thomas 1997-07-12
  *  <xd> delimited identifiers (double-quoted identifiers) - thomas 1997-10-27
  *  <xh> hexadecimal numeric string - thomas 1997-11-16
  *  <xq> quoted strings - thomas 1997-07-30
  */
 
-%x xbit
+%x xb
 %x xc
 %x xd
 %x xh
@@ -107,10 +107,10 @@ unsigned char unescape_single_char(unsigned char c);
 
 /* Bit string
  */
-xbitstart		[bB]{quote}
-xbitstop		{quote}
-xbitinside		[^']*
-xbitcat			{quote}{whitespace_with_newline}{quote}
+xbstart		[bB]{quote}
+xbstop		{quote}
+xbinside		[^']*
+xbcat			{quote}{whitespace_with_newline}{quote}
 
 /* Hexadecimal number
  */
@@ -285,13 +285,13 @@ other			.
 
 <xc><<EOF>>		{ yyerror("unterminated /* comment"); }
 
-{xbitstart}		{
+{xbstart}		{
 					token_start = yytext;
-					BEGIN(xbit);
+					BEGIN(xb);
 					startlit();
 					addlitchar('b');
 				}
-<xbit>{xbitstop}	{
+<xb>{xbstop}	{
 					BEGIN(INITIAL);
 					if (literalbuf[strspn(literalbuf + 1, "01") + 1] != '\0')
 						yyerror("invalid bit string input");
@@ -299,14 +299,14 @@ other			.
 					return BITCONST;
 				}
 <xh>{xhinside}	|
-<xbit>{xbitinside}	{
+<xb>{xbinside}	{
 					addlit(yytext, yyleng);
 				}
 <xh>{xhcat}		|
-<xbit>{xbitcat}		{
+<xb>{xbcat}		{
 					/* ignore */
 				}
-<xbit><<EOF>>		{ yyerror("unterminated bit string literal"); }
+<xb><<EOF>>		{ yyerror("unterminated bit string literal"); }
 
 {xhstart}		{
 					token_start = yytext;

src/backend/regex/regcomp.c

@@ -174,9 +174,10 @@ static int	never = 0;			/* for use in asserts; shuts lint up */
 
 /*
  * regcomp - interface for parser and compilation
+ * returns 0 success, otherwise REG_something
  */
-int								/* 0 success, otherwise REG_something */
-pg95_regcomp(regex_t *preg, const char *pattern, int cflags)
+int
+pg_regcomp(regex_t *preg, const char *pattern, int cflags)
 {
 	struct parse pa;
 	struct re_guts *g;
@@ -224,7 +225,6 @@ pg95_regcomp(regex_t *preg, const char *pattern, int cflags)
 		(void) pg_mb2wchar((unsigned char *) pattern, wcp);
 		len = pg_wchar_strlen(wcp);
 #else
-
 		len = strlen((char *) pattern);
 #endif
 	}
@@ -305,7 +305,7 @@ pg95_regcomp(regex_t *preg, const char *pattern, int cflags)
 
 	/* win or lose, we're done */
 	if (p->error != 0)			/* lose */
-		pg95_regfree(preg);
+		pg_regfree(preg);
 	return p->error;
 }
 

src/backend/regex/regerror.c

@@ -117,7 +117,7 @@ static struct rerr
  */
 /* ARGSUSED */
 size_t
-pg95_regerror(int errcode, const regex_t *preg,
+pg_regerror(int errcode, const regex_t *preg,
 			char *errbuf, size_t errbuf_size)
 {
 	struct rerr *r;

src/backend/regex/regexec.c

@@ -149,7 +149,7 @@ do { \
  * when choosing which matcher to call.
  */
 int								/* 0 success, REG_NOMATCH failure */
-pg95_regexec(const regex_t *preg, const char *string, size_t nmatch,
+pg_regexec(const regex_t *preg, const char *string, size_t nmatch,
 		   regmatch_t *pmatch, int eflags)
 {
 	struct re_guts *g = preg->re_g;

src/backend/regex/regfree.c

@@ -49,7 +49,7 @@
  * regfree - free everything
  */
 void
-pg95_regfree(regex_t *preg)
+pg_regfree(regex_t *preg)
 {
 	struct re_guts *g;
 

src/backend/regex/retest.c

 /*
  * a simple regexp debug program
  *
- * $Header: /cvsroot/pgsql/src/backend/regex/Attic/retest.c,v 1.4 1999/07/17 20:17:34 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/regex/Attic/retest.c,v 1.5 2002/06/11 15:41:37 thomas Exp $
  */
 
 #include "postgres.h"
@@ -22,7 +22,7 @@ main()
 	if (p)
 		*p = '\0';
 
-	sts = pg95_regcomp(&re, buf, 1);
+	sts = pg_regcomp(&re, buf, 1);
 	printf("regcomp: parses \"%s\" and returns %d\n", buf, sts);
 	for (;;)
 	{
@@ -33,7 +33,7 @@ main()
 		if (p)
 			*p = '\0';
 
-		sts = pg95_regexec(&re, buf, 0, 0, 0);
+		sts = pg_regexec(&re, buf, 0, 0, 0);
 		printf("regexec: returns %d\n", sts);
 	}
 }

src/backend/utils/adt/regexp.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/regexp.c,v 1.38 2001/11/05 17:46:29 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/regexp.c,v 1.39 2002/06/11 15:41:37 thomas Exp $
  *
  *		Alistair Crooks added the code for the regex caching
  *		agc - cached the regular expressions used - there's a good chance
@@ -19,7 +19,7 @@
  *
  *		agc - incorporated Keith Bostic's Berkeley regex code into
  *		the tree for all ports. To distinguish this regex code from any that
- *		is existent on a platform, I've prepended the string "pg95_" to
+ *		is existent on a platform, I've prepended the string "pg_" to
  *		the functions regcomp, regerror, regexec and regfree.
  *		Fixed a bug that was originally a typo by me, where `i' was used
  *		instead of `oldest' when compiling regular expressions - benign
@@ -53,11 +53,13 @@ struct cached_re_str
 static int	rec = 0;			/* # of cached re's */
 static struct cached_re_str rev[MAX_CACHED_RES];		/* cached re's */
 static unsigned long lru;		/* system lru tag */
+static int pg_lastre = 0;
 
 /* attempt to compile `re' as an re, then match it against text */
 /* cflags - flag to regcomp indicates case sensitivity */
 static bool
-RE_compile_and_execute(text *text_re, char *text, int cflags)
+RE_compile_and_execute(text *text_re, char *text, int cflags,
+					   int nmatch, regmatch_t *pmatch)
 {
 	char	   *re;
 	int			oldest;
@@ -68,9 +70,27 @@ RE_compile_and_execute(text *text_re, char *text, int cflags)
 	re = DatumGetCString(DirectFunctionCall1(textout,
 											 PointerGetDatum(text_re)));
 
+	if ((i = pg_lastre) < rec)
+	{
+		if (rev[i].cre_s)
+		{
+			if (strcmp(rev[i].cre_s, re) == 0 &&
+				rev[i].cre_type == cflags)
+			{
+				rev[i].cre_lru = ++lru;
+				pfree(re);
+				return (pg_regexec(&rev[i].cre_re,
+								   text, nmatch,
+								   pmatch, 0) == 0);
+			}
+		}
+	}
+
 	/* find a previously compiled regular expression */
 	for (i = 0; i < rec; i++)
 	{
+		if (i == pg_lastre) continue;
+
 		if (rev[i].cre_s)
 		{
 			if (strcmp(rev[i].cre_s, re) == 0 &&
@@ -78,9 +98,9 @@ RE_compile_and_execute(text *text_re, char *text, int cflags)
 			{
 				rev[i].cre_lru = ++lru;
 				pfree(re);
-				return (pg95_regexec(&rev[i].cre_re,
-									 text, 0,
-									 (regmatch_t *) NULL, 0) == 0);
+				return (pg_regexec(&rev[i].cre_re,
+								   text, nmatch,
+								   pmatch, 0) == 0);
 			}
 		}
 	}
@@ -107,7 +127,7 @@ RE_compile_and_execute(text *text_re, char *text, int cflags)
 			if (rev[i].cre_lru > lru)
 				lru = rev[i].cre_lru;
 		}
-		pg95_regfree(&rev[oldest].cre_re);
+		pg_regfree(&rev[oldest].cre_re);
 
 		/*
 		 * use malloc/free for the cre_s field because the storage has to
@@ -118,7 +138,7 @@ RE_compile_and_execute(text *text_re, char *text, int cflags)
 	}
 
 	/* compile the re */
-	regcomp_result = pg95_regcomp(&rev[oldest].cre_re, re, cflags);
+	regcomp_result = pg_regcomp(&rev[oldest].cre_re, re, cflags);
 	if (regcomp_result == 0)
 	{
 		/*
@@ -130,15 +150,15 @@ RE_compile_and_execute(text *text_re, char *text, int cflags)
 		rev[oldest].cre_type = cflags;
 		pfree(re);
 		/* agc - fixed an old typo here */
-		return (pg95_regexec(&rev[oldest].cre_re, text, 0,
-							 (regmatch_t *) NULL, 0) == 0);
+		return (pg_regexec(&rev[oldest].cre_re, text,
+						   nmatch, pmatch, 0) == 0);
 	}
 	else
 	{
 		char		errMsg[1000];
 
 		/* re didn't compile */
-		pg95_regerror(regcomp_result, &rev[oldest].cre_re, errMsg,
+		pg_regerror(regcomp_result, &rev[oldest].cre_re, errMsg,
 					sizeof(errMsg));
 		elog(ERROR, "Invalid regular expression: %s", errMsg);
 	}
@@ -167,7 +187,7 @@ fixedlen_regexeq(char *s, text *p, int charlen, int cflags)
 	memcpy(sterm, s, charlen);
 	sterm[charlen] = '\0';
 
-	result = RE_compile_and_execute(p, sterm, cflags);
+	result = RE_compile_and_execute(p, sterm, cflags, 0, NULL);
 
 	pfree(sterm);
 
@@ -230,7 +250,7 @@ textregexne(PG_FUNCTION_ARGS)
 
 /*
  *	routines that use the regexp stuff, but ignore the case.
- *	for this, we use the REG_ICASE flag to pg95_regcomp
+ *	for this, we use the REG_ICASE flag to pg_regcomp
  */
 
 
@@ -281,3 +301,54 @@ nameicregexne(PG_FUNCTION_ARGS)
 									 strlen(NameStr(*n)),
 									 REG_ICASE | REG_EXTENDED));
 }
+
+
+/* textregexsubstr()
+ * Return a substring matched by a regular expression.
+ */
+Datum
+textregexsubstr(PG_FUNCTION_ARGS)
+{
+	text	   *s = PG_GETARG_TEXT_P(0);
+	text	   *p = PG_GETARG_TEXT_P(1);
+	text	   *result;
+	char	   *sterm;
+	int			len;
+	bool		match;
+	int			nmatch = 1;
+	regmatch_t	pmatch;
+
+	/* be sure sterm is null-terminated */
+	len = VARSIZE(s) - VARHDRSZ;
+	sterm = (char *) palloc(len + 1);
+	memcpy(sterm, VARDATA(s), len);
+	sterm[len] = '\0';
+	/* We need the match info back from the pattern match
+	 * to be able to actually extract the substring.
+	 * It seems to be adequate to pass in a structure to return
+	 * only one result.
+	 */
+	match = RE_compile_and_execute(p, sterm, REG_EXTENDED, nmatch, &pmatch);
+	pfree(sterm);
+
+	/* match? then return the substring matching the pattern */
+	if (match)
+	{
+		return (DirectFunctionCall3(text_substr,
+									PointerGetDatum(s),
+									Int32GetDatum(pmatch.rm_so+1),
+									Int32GetDatum(pmatch.rm_eo-pmatch.rm_so)));
+	}
+#if 0
+	/* otherwise, return a zero-length string */
+	else
+	{
+		result = palloc(VARHDRSZ);
+		VARATT_SIZEP(result) = VARHDRSZ;
+		PG_RETURN_TEXT_P(result);
+	}
+#endif
+
+	/* not reached */
+	PG_RETURN_NULL();
+}

src/include/catalog/catversion.h

@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: catversion.h,v 1.133 2002/05/22 17:21:01 petere Exp $
+ * $Id: catversion.h,v 1.134 2002/06/11 15:44:38 thomas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	200205221
+#define CATALOG_VERSION_NO	200206111
 
 #endif

src/include/catalog/pg_proc.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: pg_proc.h,v 1.240 2002/05/24 18:57:56 tgl Exp $
+ * $Id: pg_proc.h,v 1.241 2002/06/11 15:41:37 thomas Exp $
  *
  * NOTES
  *	  The script catalog/genbki.sh reads this file and generates .bki
@@ -1764,6 +1764,11 @@ DESCR("current schema name");
 DATA(insert OID = 1403 (  current_schemas	PGNSP PGUID 12 f f f t f s 0  1003 "0" 100 0 0 100	current_schemas - _null_ ));
 DESCR("current schema search list");
 
+DATA(insert OID = 1404 (  overlay			PGNSP PGUID 14 f f f t f i 4 25 "25 25 23 23" 100 0 0 100  "select substring($1, 1, ($3 - 1)) || $2 || substring($1, ($3 + $4))" - _null_ ));
+DESCR("substitute portion of string");
+DATA(insert OID = 1405 (  overlay			PGNSP PGUID 14 f f f t f i 3 25 "25 25 23" 100 0 0 100  "select substring($1, 1, ($3 - 1)) || $2 || substring($1, ($3 + char_length($2)))" - _null_ ));
+DESCR("substitute portion of string");
+
 DATA(insert OID = 1406 (  isvertical		PGNSP PGUID 12 f f f t f i 2	16 "600 600" 100 0 0 100  point_vert - _null_ ));
 DESCR("vertically aligned?");
 DATA(insert OID = 1407 (  ishorizontal		PGNSP PGUID 12 f f f t f i 2	16 "600 600" 100 0 0 100  point_horiz - _null_ ));
@@ -2871,6 +2876,11 @@ DESCR("add");
 DATA(insert OID = 2072 (  date_mi_interval	PGNSP PGUID 14 f f f t f i 2 1114 "1082 1186" 100 0 0 100  "select cast($1 as timestamp without time zone) - $2;" - _null_ ));
 DESCR("subtract");
 
+DATA(insert OID = 2073 (  substring			PGNSP PGUID 12 f f f t f i 2 25 "25 25" 100 0 0 100	textregexsubstr - _null_ ));
+DESCR("substitutes regular expression");
+DATA(insert OID = 2074 (  substring			PGNSP PGUID 14 f f f t f i 3 25 "25 25 25" 100 0 0 100	"select substring($1, like_escape($2, $3))" - _null_ ));
+DESCR("substitutes regular expression with escape argument");
+
 /* Aggregates (moved here from pg_aggregate for 7.3) */
 
 DATA(insert OID = 2100 (  avg				PGNSP PGUID 12 t f f f f i 1 1700 "20" 100 0 0 100  aggregate_dummy - _null_ ));

src/include/regex/regex.h

@@ -53,7 +53,7 @@ typedef struct
 	const pg_wchar *re_endp;	/* end pointer for REG_PEND */
 	struct re_guts *re_g;		/* none of your business :-) */
 #ifdef MULTIBYTE
-	pg_wchar   *patsave;		/* mee too :-) */
+	pg_wchar   *patsave;		/* me too :-) */
 #endif
 
 } regex_t;
@@ -102,12 +102,12 @@ typedef struct
 #define REG_LARGE		01000	/* force large representation */
 #define REG_BACKR		02000	/* force use of backref code */
 
-extern int	pg95_regcomp(regex_t *preg, const char *pattern, int cflags);
-extern size_t pg95_regerror(int errcode, const regex_t *preg,
+extern int	pg_regcomp(regex_t *preg, const char *pattern, int cflags);
+extern size_t pg_regerror(int errcode, const regex_t *preg,
 						  char *errbuf, size_t errbuf_size);
-extern int pg95_regexec(const regex_t *preg, const char *string,
+extern int pg_regexec(const regex_t *preg, const char *string,
 					  size_t nmatch,
 					  regmatch_t *pmatch, int eflags);
-extern void pg95_regfree(regex_t *preg);
+extern void pg_regfree(regex_t *preg);
 
 #endif   /* !_REGEX_H_ */

src/include/utils/builtins.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: builtins.h,v 1.182 2002/05/18 21:38:41 tgl Exp $
+ * $Id: builtins.h,v 1.183 2002/06/11 15:41:38 thomas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -327,6 +327,7 @@ extern Datum nameicregexeq(PG_FUNCTION_ARGS);
 extern Datum nameicregexne(PG_FUNCTION_ARGS);
 extern Datum texticregexeq(PG_FUNCTION_ARGS);
 extern Datum texticregexne(PG_FUNCTION_ARGS);
+extern Datum textregexsubstr(PG_FUNCTION_ARGS);
 
 /* regproc.c */
 extern Datum regprocin(PG_FUNCTION_ARGS);

src/test/regress/expected/strings.out

@@ -3,6 +3,7 @@
 -- Test various data entry syntaxes.
 --
 -- SQL92 string continuation syntax
+-- E021-03 character string literals
 SELECT 'first line'
 ' - next line'
 	' - third line'
@@ -20,6 +21,7 @@ SELECT 'first line'
 ERROR:  parser: parse error at or near "' - third line'"
 --
 -- test conversions between various string types
+-- E021-10 implicit casting among the character data types
 --
 SELECT CAST(f1 AS text) AS "text(char)" FROM CHAR_TBL;
  text(char) 
@@ -93,7 +95,9 @@ SELECT CAST(name 'namefield' AS varchar) AS "varchar(name)";
 
 --
 -- test SQL92 string functions
+-- E### and T### are feature reference numbers from SQL99
 --
+-- E021-09 trim function
 SELECT TRIM(BOTH FROM '  bunch o blanks  ') = 'bunch o blanks' AS "bunch o blanks";
  bunch o blanks 
 ----------------
@@ -118,6 +122,7 @@ SELECT TRIM(BOTH 'x' FROM 'xxxxxsome Xsxxxxx') = 'some Xs' AS "some Xs";
  t
 (1 row)
 
+-- E021-06 substring expression
 SELECT SUBSTRING('1234567890' FROM 3) = '34567890' AS "34567890";
  34567890 
 ----------
@@ -130,6 +135,47 @@ SELECT SUBSTRING('1234567890' FROM 4 FOR 3) = '456' AS "456";
  t
 (1 row)
 
+-- T581 regular expression substring
+SELECT SUBSTRING('abcdefg' FROM '(b|f).*(d)' FOR '#') AS "bcd";
+ bcd 
+-----
+ bcd
+(1 row)
+
+-- No match should return NULL
+SELECT SUBSTRING('abcdefg' FROM '(1|2|3)' FOR '#') IS NULL AS "True";
+ True 
+------
+ t
+(1 row)
+
+-- Null inputs should return NULL
+SELECT SUBSTRING('abcdefg' FROM '(b|c)' FOR NULL) IS NULL AS "True";
+ True 
+------
+ t
+(1 row)
+
+SELECT SUBSTRING(NULL FROM '(b|c)' FOR '#') IS NULL AS "True";
+ True 
+------
+ t
+(1 row)
+
+SELECT SUBSTRING('abcdefg' FROM NULL FOR '#') IS NULL AS "True";
+ True 
+------
+ t
+(1 row)
+
+-- PostgreSQL extention to allow omitting the escape character
+SELECT SUBSTRING('abcdefg' FROM '(c|d).e') AS "cde";
+ cde 
+-----
+ cde
+(1 row)
+
+-- E021-11 position expression
 SELECT POSITION('4' IN '1234567890') = '4' AS "4";
  4 
 ---
@@ -142,11 +188,37 @@ SELECT POSITION(5 IN '1234567890') = '5' AS "5";
  t
 (1 row)
 
+-- T312 character overlay function
+SELECT OVERLAY('abcdef' PLACING '45' FROM 4) AS "abc45f";
+ abc45f 
+--------
+ abc45f
+(1 row)
+
+SELECT OVERLAY('yabadoo' PLACING 'daba' FROM 5) AS "yabadaba";
+ yabadaba 
+----------
+ yabadaba
+(1 row)
+
+SELECT OVERLAY('yabadoo' PLACING 'daba' FROM 5 FOR 0) AS "yabadabadoo";
+ yabadabadoo 
+-------------
+ yabadabadoo
+(1 row)
+
+SELECT OVERLAY('babosa' PLACING 'ubb' FROM 2 FOR 4) AS "bubba";
+ bubba 
+-------
+ bubba
+(1 row)
+
 --
 -- test LIKE
 -- Be sure to form every test as a LIKE/NOT LIKE pair.
 --
 -- simplest examples
+-- E061-04 like predicate
 SELECT 'hawkeye' LIKE 'h%' AS "true";
  true 
 ------
@@ -257,6 +329,7 @@ SELECT 'indio' NOT LIKE 'ind_o' ESCAPE '$' AS "false";
 (1 row)
 
 -- escape character
+-- E061-05 like predicate with escape clause
 SELECT 'h%' LIKE 'h#%' ESCAPE '#' AS "true";
  true 
 ------
@@ -469,6 +542,7 @@ SELECT 'Hawkeye' NOT ILIKE 'h%' AS "false";
 --
 -- test implicit type conversion
 --
+-- E021-07 character concatenation
 SELECT 'unknown' || ' and unknown' AS "Concat unknown types";
  Concat unknown types 
 ----------------------

src/test/regress/sql/strings.sql

@@ -4,6 +4,7 @@
 --
 
 -- SQL92 string continuation syntax
+-- E021-03 character string literals
 SELECT 'first line'
 ' - next line'
 	' - third line'
@@ -17,6 +18,7 @@ SELECT 'first line'
 
 --
 -- test conversions between various string types
+-- E021-10 implicit casting among the character data types
 --
 
 SELECT CAST(f1 AS text) AS "text(char)" FROM CHAR_TBL;
@@ -41,8 +43,10 @@ SELECT CAST(name 'namefield' AS varchar) AS "varchar(name)";
 
 --
 -- test SQL92 string functions
+-- E### and T### are feature reference numbers from SQL99
 --
 
+-- E021-09 trim function
 SELECT TRIM(BOTH FROM '  bunch o blanks  ') = 'bunch o blanks' AS "bunch o blanks";
 
 SELECT TRIM(LEADING FROM '  bunch o blanks  ') = 'bunch o blanks  ' AS "bunch o blanks  ";
@@ -51,20 +55,46 @@ SELECT TRIM(TRAILING FROM '  bunch o blanks  ') = '  bunch o blanks' AS "  bunch
 
 SELECT TRIM(BOTH 'x' FROM 'xxxxxsome Xsxxxxx') = 'some Xs' AS "some Xs";
 
+-- E021-06 substring expression
 SELECT SUBSTRING('1234567890' FROM 3) = '34567890' AS "34567890";
 
 SELECT SUBSTRING('1234567890' FROM 4 FOR 3) = '456' AS "456";
 
+-- T581 regular expression substring
+SELECT SUBSTRING('abcdefg' FROM '(b|f).*(d)' FOR '#') AS "bcd";
+
+-- No match should return NULL
+SELECT SUBSTRING('abcdefg' FROM '(1|2|3)' FOR '#') IS NULL AS "True";
+
+-- Null inputs should return NULL
+SELECT SUBSTRING('abcdefg' FROM '(b|c)' FOR NULL) IS NULL AS "True";
+SELECT SUBSTRING(NULL FROM '(b|c)' FOR '#') IS NULL AS "True";
+SELECT SUBSTRING('abcdefg' FROM NULL FOR '#') IS NULL AS "True";
+
+-- PostgreSQL extention to allow omitting the escape character
+SELECT SUBSTRING('abcdefg' FROM '(c|d).e') AS "cde";
+
+-- E021-11 position expression
 SELECT POSITION('4' IN '1234567890') = '4' AS "4";
 
 SELECT POSITION(5 IN '1234567890') = '5' AS "5";
 
+-- T312 character overlay function
+SELECT OVERLAY('abcdef' PLACING '45' FROM 4) AS "abc45f";
+
+SELECT OVERLAY('yabadoo' PLACING 'daba' FROM 5) AS "yabadaba";
+
+SELECT OVERLAY('yabadoo' PLACING 'daba' FROM 5 FOR 0) AS "yabadabadoo";
+
+SELECT OVERLAY('babosa' PLACING 'ubb' FROM 2 FOR 4) AS "bubba";
+
 --
 -- test LIKE
 -- Be sure to form every test as a LIKE/NOT LIKE pair.
 --
 
 -- simplest examples
+-- E061-04 like predicate
 SELECT 'hawkeye' LIKE 'h%' AS "true";
 SELECT 'hawkeye' NOT LIKE 'h%' AS "false";
 
@@ -94,6 +124,7 @@ SELECT 'indio' LIKE 'ind_o' ESCAPE '$' AS "true";
 SELECT 'indio' NOT LIKE 'ind_o' ESCAPE '$' AS "false";
 
 -- escape character
+-- E061-05 like predicate with escape clause
 SELECT 'h%' LIKE 'h#%' ESCAPE '#' AS "true";
 SELECT 'h%' NOT LIKE 'h#%' ESCAPE '#' AS "false";
 
@@ -156,6 +187,7 @@ SELECT 'Hawkeye' NOT ILIKE 'h%' AS "false";
 -- test implicit type conversion
 --
 
+-- E021-07 character concatenation
 SELECT 'unknown' || ' and unknown' AS "Concat unknown types";
 
 SELECT text 'text' || ' and unknown' AS "Concat text to unknown type";
@@ -165,4 +197,3 @@ SELECT char(20) 'characters' || 'and text' AS "Concat char to unknown type";
 SELECT text 'text' || char(20) ' and characters' AS "Concat text to char";
 
 SELECT text 'text' || varchar ' and varchar' AS "Concat text to varchar";
-