open-dsi
/
postgres
mirror of https://github.com/postgres/postgres
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Bring SIMILAR TO and SUBSTRING into some semblance of conformance with

Browse Source 
the SQL99 standard.  (I'm not sure that the character-class features are
quite right, but that can be fixed later.)  Document SQL99 and POSIX
regexps as being different features; provide variants of SUBSTRING for
each.
REL7_3_STABLE
Tom Lane 23 years ago
parent ac355d558e
commit 9946b83ded
7 changed files with 722 additions and 420 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Show Stats Download Patch File Download Diff File
  1. 936
      doc/src/sgml/func.sgml
  2. 28
      src/backend/parser/gram.y
  3. 127
      src/backend/utils/adt/regexp.c
  4. 15
      src/include/catalog/pg_proc.h
  5. 3
      src/include/utils/builtins.h
  6. 18
      src/test/regress/expected/strings.out
  7. 15
      src/test/regress/sql/strings.sql

936
doc/src/sgml/func.sgml
View File

File diff suppressed because it is too large Load Diff

28
src/backend/parser/gram.y
Unescape View File

@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.367 2002/09/18 21:35:21 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.368 2002/09/22 17:27:23 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@ -5644,22 +5644,40 @@ a_expr: c_expr { $$ = $1; }
}
| a_expr SIMILAR TO a_expr %prec SIMILAR
{ $$ = (Node *) makeSimpleA_Expr(OP, "~", $1, $4); }
{
A_Const *c = makeNode(A_Const);
FuncCall *n = makeNode(FuncCall);
c->val.type = T_Null;
n->funcname = SystemFuncName("similar_escape");
n->args = makeList2($4, (Node *) c);
n->agg_star = FALSE;
n->agg_distinct = FALSE;
$$ = (Node *) makeSimpleA_Expr(OP, "~", $1, (Node *) n);
}
| a_expr SIMILAR TO a_expr ESCAPE a_expr
{
FuncCall *n = makeNode(FuncCall);
n->funcname = SystemFuncName("like_escape");
n->funcname = SystemFuncName("similar_escape");
n->args = makeList2($4, $6);
n->agg_star = FALSE;
n->agg_distinct = FALSE;
$$ = (Node *) makeSimpleA_Expr(OP, "~", $1, (Node *) n);
}
| a_expr NOT SIMILAR TO a_expr %prec SIMILAR
{ $$ = (Node *) makeSimpleA_Expr(OP, "!~", $1, $5); }
{
A_Const *c = makeNode(A_Const);
FuncCall *n = makeNode(FuncCall);
c->val.type = T_Null;
n->funcname = SystemFuncName("similar_escape");
n->args = makeList2($5, (Node *) c);
n->agg_star = FALSE;
n->agg_distinct = FALSE;
$$ = (Node *) makeSimpleA_Expr(OP, "!~", $1, (Node *) n);
}
| a_expr NOT SIMILAR TO a_expr ESCAPE a_expr
{
FuncCall *n = makeNode(FuncCall);
n->funcname = SystemFuncName("like_escape");
n->funcname = SystemFuncName("similar_escape");
n->args = makeList2($5, $7);
n->agg_star = FALSE;
n->agg_distinct = FALSE;

127
src/backend/utils/adt/regexp.c
Unescape View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/regexp.c,v 1.42 2002/09/04 20:31:28 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/regexp.c,v 1.43 2002/09/22 17:27:23 tgl Exp $
*
* Alistair Crooks added the code for the regex caching
* agc - cached the regular expressions used - there's a good chance
@ -317,8 +317,7 @@ textregexsubstr(PG_FUNCTION_ARGS)
char *sterm;
int len;
bool match;
int nmatch = 1;
regmatch_t pmatch;
regmatch_t pmatch[2];
/* be sure sterm is null-terminated */
len = VARSIZE(s) - VARHDRSZ;
@ -327,21 +326,131 @@ textregexsubstr(PG_FUNCTION_ARGS)
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.
* We pass two regmatch_t structs to get info about the overall match
* and the match for the first parenthesized subexpression (if any).
* If there is a parenthesized subexpression, we return what it matched;
* else return what the whole regexp matched.
*/
match = RE_compile_and_execute(p, sterm, REG_EXTENDED, nmatch, &pmatch);
match = RE_compile_and_execute(p, sterm, REG_EXTENDED, 2, pmatch);
pfree(sterm);
/* match? then return the substring matching the pattern */
if (match)
{
int so,
eo;
so = pmatch[1].rm_so;
eo = pmatch[1].rm_eo;
if (so < 0 || eo < 0)
{
/* no parenthesized subexpression */
so = pmatch[0].rm_so;
eo = pmatch[0].rm_eo;
}
return (DirectFunctionCall3(text_substr,
PointerGetDatum(s),
Int32GetDatum(pmatch.rm_so + 1),
Int32GetDatum(pmatch.rm_eo - pmatch.rm_so)));
Int32GetDatum(so + 1),
Int32GetDatum(eo - so)));
}
PG_RETURN_NULL();
}
/* similar_escape()
* Convert a SQL99 regexp pattern to POSIX style, so it can be used by
* our regexp engine.
*/
Datum
similar_escape(PG_FUNCTION_ARGS)
{
text *pat_text;
text *esc_text;
text *result;
unsigned char *p,
*e,
*r;
int plen,
elen;
bool afterescape = false;
int nquotes = 0;
/* This function is not strict, so must test explicitly */
if (PG_ARGISNULL(0))
PG_RETURN_NULL();
pat_text = PG_GETARG_TEXT_P(0);
p = VARDATA(pat_text);
plen = (VARSIZE(pat_text) - VARHDRSZ);
if (PG_ARGISNULL(1))
{
/* No ESCAPE clause provided; default to backslash as escape */
e = "\\";
elen = 1;
}
else
{
esc_text = PG_GETARG_TEXT_P(1);
e = VARDATA(esc_text);
elen = (VARSIZE(esc_text) - VARHDRSZ);
if (elen == 0)
e = NULL; /* no escape character */
else if (elen != 1)
elog(ERROR, "ESCAPE string must be empty or one character");
}
/* We need room for ^, $, and up to 2 output bytes per input byte */
result = (text *) palloc(VARHDRSZ + 2 + 2 * plen);
r = VARDATA(result);
*r++ = '^';
while (plen > 0)
{
unsigned char pchar = *p;
if (afterescape)
{
if (pchar == '"') /* for SUBSTRING patterns */
*r++ = ((nquotes++ % 2) == 0) ? '(' : ')';
else
{
*r++ = '\\';
*r++ = pchar;
}
afterescape = false;
}
else if (e && pchar == *e)
{
/* SQL99 escape character; do not send to output */
afterescape = true;
}
else if (pchar == '%')
{
*r++ = '.';
*r++ = '*';
}
else if (pchar == '_')
{
*r++ = '.';
}
else if (pchar == '\\' || pchar == '.' || pchar == '?' ||
pchar == '{')
{
*r++ = '\\';
*r++ = pchar;
}
else
{
*r++ = pchar;
}
p++, plen--;
}
*r++ = '$';
VARATT_SIZEP(result) = r - ((unsigned char *) result);
PG_RETURN_TEXT_P(result);
}

15
src/include/catalog/pg_proc.h
Unescape View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: pg_proc.h,v 1.272 2002/09/18 21:35:23 tgl Exp $
* $Id: pg_proc.h,v 1.273 2002/09/22 17:27:23 tgl Exp $
*
* NOTES
* The script catalog/genbki.sh reads this file and generates .bki
@ -2076,6 +2076,9 @@ DESCR("convert int4 to char");
DATA(insert OID = 1622 ( repeat PGNSP PGUID 12 f f t f i 2 25 "25 23" repeat - _null_ ));
DESCR("replicate string int4 times");
DATA(insert OID = 1623 ( similar_escape PGNSP PGUID 12 f f f f i 2 25 "25 25" similar_escape - _null_ ));
DESCR("convert SQL99 regexp pattern to POSIX style");
DATA(insert OID = 1624 ( mul_d_interval PGNSP PGUID 12 f f t f i 2 1186 "701 1186" mul_d_interval - _null_ ));
DATA(insert OID = 1633 ( texticlike PGNSP PGUID 12 f f t f i 2 16 "25 25" texticlike - _null_ ));
@ -2087,7 +2090,7 @@ DESCR("matches LIKE expression, case-insensitive");
DATA(insert OID = 1636 ( nameicnlike PGNSP PGUID 12 f f t f i 2 16 "19 25" nameicnlike - _null_ ));
DESCR("does not match LIKE expression, case-insensitive");
DATA(insert OID = 1637 ( like_escape PGNSP PGUID 12 f f t f i 2 25 "25 25" like_escape - _null_ ));
DESCR("convert match pattern to use backslash escapes");
DESCR("convert LIKE pattern to use backslash escapes");
DATA(insert OID = 1689 ( update_pg_pwd_and_pg_group PGNSP PGUID 12 f f t f v 0 2279 "" update_pg_pwd_and_pg_group - _null_ ));
DESCR("update pg_pwd and pg_group files");
@ -2784,7 +2787,7 @@ DESCR("matches LIKE expression");
DATA(insert OID = 2008 ( notlike PGNSP PGUID 12 f f t f i 2 16 "17 17" byteanlike - _null_ ));
DESCR("does not match LIKE expression");
DATA(insert OID = 2009 ( like_escape PGNSP PGUID 12 f f t f i 2 17 "17 17" like_escape_bytea - _null_ ));
DESCR("convert match pattern to use backslash escapes");
DESCR("convert LIKE pattern to use backslash escapes");
DATA(insert OID = 2010 ( length PGNSP PGUID 12 f f t f i 1 23 "17" byteaoctetlen - _null_ ));
DESCR("octet length");
DATA(insert OID = 2011 ( byteacat PGNSP PGUID 12 f f t f i 2 17 "17 17" byteacat - _null_ ));
@ -2889,9 +2892,9 @@ DATA(insert OID = 2072 ( date_mi_interval PGNSP PGUID 14 f f t f i 2 1114 "1082
DESCR("subtract");
DATA(insert OID = 2073 ( substring PGNSP PGUID 12 f f t f i 2 25 "25 25" textregexsubstr - _null_ ));
DESCR("substitutes regular expression");
DATA(insert OID = 2074 ( substring PGNSP PGUID 14 f f t f i 3 25 "25 25 25" "select substring($1, like_escape($2, $3))" - _null_ ));
DESCR("substitutes regular expression with escape argument");
DESCR("extracts text matching regular expression");
DATA(insert OID = 2074 ( substring PGNSP PGUID 14 f f t f i 3 25 "25 25 25" "select substring($1, similar_escape($2, $3))" - _null_ ));
DESCR("extracts text matching SQL99 regular expression");
DATA(insert OID = 2075 ( bit PGNSP PGUID 12 f f t f i 1 1560 "20" bitfromint8 - _null_ ));
DESCR("int8 to bitstring");

3
src/include/utils/builtins.h
Unescape View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: builtins.h,v 1.201 2002/09/19 22:48:34 tgl Exp $
* $Id: builtins.h,v 1.202 2002/09/22 17:27:25 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -371,6 +371,7 @@ extern Datum nameicregexne(PG_FUNCTION_ARGS);
extern Datum texticregexeq(PG_FUNCTION_ARGS);
extern Datum texticregexne(PG_FUNCTION_ARGS);
extern Datum textregexsubstr(PG_FUNCTION_ARGS);
extern Datum similar_escape(PG_FUNCTION_ARGS);
/* regproc.c */
extern Datum regprocin(PG_FUNCTION_ARGS);

18
src/test/regress/expected/strings.out
Unescape View File

@ -142,15 +142,15 @@ 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";
-- T581 regular expression substring (with SQL99's bizarre regexp syntax)
SELECT SUBSTRING('abcdefg' FROM 'a#"(b_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";
SELECT SUBSTRING('abcdefg' FROM '#"(b_d)#"%' FOR '#') IS NULL AS "True";
True
------
t
@ -175,8 +175,16 @@ SELECT SUBSTRING('abcdefg' FROM NULL FOR '#') IS NULL AS "True";
t
(1 row)
-- PostgreSQL extention to allow omitting the escape character
SELECT SUBSTRING('abcdefg' FROM '(c|d).e') AS "cde";
-- PostgreSQL extension to allow omitting the escape character;
-- here the regexp is taken as Posix syntax
SELECT SUBSTRING('abcdefg' FROM 'c.e') AS "cde";
cde
-----
cde
(1 row)
-- With a parenthesized subexpression, return only what matches the subexpr
SELECT SUBSTRING('abcdefg' FROM 'b(.*)f') AS "cde";
cde
-----
cde

15
src/test/regress/sql/strings.sql
Unescape View File

@ -62,19 +62,24 @@ 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";
-- T581 regular expression substring (with SQL99's bizarre regexp syntax)
SELECT SUBSTRING('abcdefg' FROM 'a#"(b_d)#"%' FOR '#') AS "bcd";
-- No match should return NULL
SELECT SUBSTRING('abcdefg' FROM '(1|2|3)' FOR '#') IS NULL AS "True";
SELECT SUBSTRING('abcdefg' FROM '#"(b_d)#"%' 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";
-- PostgreSQL extension to allow omitting the escape character;
-- here the regexp is taken as Posix syntax
SELECT SUBSTRING('abcdefg' FROM 'c.e') AS "cde";
-- With a parenthesized subexpression, return only what matches the subexpr
SELECT SUBSTRING('abcdefg' FROM 'b(.*)f') AS "cde";
-- E021-11 position expression
SELECT POSITION('4' IN '1234567890') = '4' AS "4";

Write Preview
Loading…
Cancel
Save