Implement LIKE/ESCAPE. Change parser to use like()/notlike()

rather than the "~~" operator; this made it easy to add ESCAPE features.
Implement ILIKE, NOT ILIKE, and the ESCAPE clause for them.
 afaict this is not MultiByte clean, but lots of other stuff isn't either.
Fix up underlying support code for LIKE/NOT LIKE.
 Things should be faster and does not require internal string copying.
Update regression test to add explicit checks for
 LIKE/NOT LIKE/ILIKE/NOT ILIKE.
Remove colon and semi-colon operators as threatened in 7.0.
Implement SQL99 COMMIT/AND NO CHAIN.
 Throw elog(ERROR) on COMMIT/AND CHAIN per spec
 since we don't yet support it.
Implement SQL99 CREATE/DROP SCHEMA as equivalent to CREATE DATABASE.
 This is only a stopgap or demo since schemas will have another
 implementation soon.
Remove a few unused production rules to get rid of warnings
 which crept in on the last commit.
Fix up tabbing in some places by removing embedded spaces.

src/test/regress/sql/strings.sql

@@ -41,21 +41,114 @@ SELECT CAST(name 'namefield' AS varchar) AS "varchar(name)";
 -- test SQL92 string functions
 --
 
-SELECT TRIM(BOTH FROM '  bunch o blanks  ') AS "bunch o blanks";
+SELECT TRIM(BOTH FROM '  bunch o blanks  ') = 'bunch o blanks' AS "bunch o blanks";
 
-SELECT TRIM(LEADING FROM '  bunch o blanks  ') AS "bunch o blanks  ";
+SELECT TRIM(LEADING FROM '  bunch o blanks  ') = 'bunch o blanks  ' AS "bunch o blanks  ";
 
-SELECT TRIM(TRAILING FROM '  bunch o blanks  ') AS "  bunch o blanks";
+SELECT TRIM(TRAILING FROM '  bunch o blanks  ') = '  bunch o blanks' AS "  bunch o blanks";
 
-SELECT TRIM(BOTH 'x' FROM 'xxxxxsome Xsxxxxx') AS "some Xs";
+SELECT TRIM(BOTH 'x' FROM 'xxxxxsome Xsxxxxx') = 'some Xs' AS "some Xs";
 
-SELECT SUBSTRING('1234567890' FROM 3) AS "34567890";
+SELECT SUBSTRING('1234567890' FROM 3) = '34567890' AS "34567890";
 
-SELECT SUBSTRING('1234567890' FROM 4 FOR 3) AS "456";
+SELECT SUBSTRING('1234567890' FROM 4 FOR 3) = '456' AS "456";
 
-SELECT POSITION('4' IN '1234567890') AS "4";
+SELECT POSITION('4' IN '1234567890') = '4' AS "4";
 
-SELECT POSITION(5 IN '1234567890') AS "5";
+SELECT POSITION(5 IN '1234567890') = '5' AS "5";
+
+--
+-- test LIKE
+-- Be sure to form every test as a LIKE/NOT LIKE pair.
+--
+
+-- simplest examples
+SELECT 'hawkeye' LIKE 'h%' AS "true";
+SELECT 'hawkeye' NOT LIKE 'h%' AS "false";
+
+SELECT 'hawkeye' LIKE 'H%' AS "false";
+SELECT 'hawkeye' NOT LIKE 'H%' AS "true";
+
+SELECT 'hawkeye' LIKE 'indio%' AS "false";
+SELECT 'hawkeye' NOT LIKE 'indio%' AS "true";
+
+SELECT 'hawkeye' LIKE 'h%eye' AS "true";
+SELECT 'hawkeye' NOT LIKE 'h%eye' AS "false";
+
+SELECT 'indio' LIKE '_ndio' AS "true";
+SELECT 'indio' NOT LIKE '_ndio' AS "false";
+
+SELECT 'indio' LIKE 'in__o' AS "true";
+SELECT 'indio' NOT LIKE 'in__o' AS "false";
+
+SELECT 'indio' LIKE 'in_o' AS "false";
+SELECT 'indio' NOT LIKE 'in_o' AS "true";
+
+-- unused escape character
+SELECT 'hawkeye' LIKE 'h%' ESCAPE '#' AS "true";
+SELECT 'hawkeye' NOT LIKE 'h%' ESCAPE '#' AS "false";
+
+SELECT 'indio' LIKE 'ind_o' ESCAPE '$' AS "true";
+SELECT 'indio' NOT LIKE 'ind_o' ESCAPE '$' AS "false";
+
+-- escape character
+SELECT 'h%' LIKE 'h#%' ESCAPE '#' AS "true";
+SELECT 'h%' NOT LIKE 'h#%' ESCAPE '#' AS "false";
+
+SELECT 'h%wkeye' LIKE 'h#%' ESCAPE '#' AS "false";
+SELECT 'h%wkeye' NOT LIKE 'h#%' ESCAPE '#' AS "true";
+
+SELECT 'h%wkeye' LIKE 'h#%%' ESCAPE '#' AS "true";
+SELECT 'h%wkeye' NOT LIKE 'h#%%' ESCAPE '#' AS "false";
+
+SELECT 'h%awkeye' LIKE 'h#%a%k%e' ESCAPE '#' AS "true";
+SELECT 'h%awkeye' NOT LIKE 'h#%a%k%e' ESCAPE '#' AS "false";
+
+SELECT 'indio' LIKE '_ndio' ESCAPE '$' AS "true";
+SELECT 'indio' NOT LIKE '_ndio' ESCAPE '$' AS "false";
+
+SELECT 'i_dio' LIKE 'i$_d_o' ESCAPE '$' AS "true";
+SELECT 'i_dio' NOT LIKE 'i$_d_o' ESCAPE '$' AS "false";
+
+SELECT 'i_dio' LIKE 'i$_nd_o' ESCAPE '$' AS "false";
+SELECT 'i_dio' NOT LIKE 'i$_nd_o' ESCAPE '$' AS "true";
+
+SELECT 'i_dio' LIKE 'i$_d%o' ESCAPE '$' AS "true";
+SELECT 'i_dio' NOT LIKE 'i$_d%o' ESCAPE '$' AS "false";
+
+-- escape character same as pattern character
+SELECT 'maca' LIKE 'm%aca' ESCAPE '%' AS "true";
+SELECT 'maca' NOT LIKE 'm%aca' ESCAPE '%' AS "false";
+
+SELECT 'ma%a' LIKE 'm%a%%a' ESCAPE '%' AS "true";
+SELECT 'ma%a' NOT LIKE 'm%a%%a' ESCAPE '%' AS "false";
+
+SELECT 'bear' LIKE 'b_ear' ESCAPE '_' AS "true";
+SELECT 'bear' NOT LIKE 'b_ear' ESCAPE '_' AS "false";
+
+SELECT 'be_r' LIKE 'b_e__r' ESCAPE '_' AS "true";
+SELECT 'be_r' NOT LIKE 'b_e__r' ESCAPE '_' AS "false";
+
+SELECT 'be_r' LIKE '__e__r' ESCAPE '_' AS "false";
+SELECT 'be_r' NOT LIKE '__e__r' ESCAPE '_' AS "true";
+
+
+--
+-- test ILIKE (case-insensitive LIKE)
+-- Be sure to form every test as an ILIKE/NOT ILIKE pair.
+--
+
+SELECT 'hawkeye' ILIKE 'h%' AS "true";
+SELECT 'hawkeye' NOT ILIKE 'h%' AS "false";
+
+SELECT 'hawkeye' ILIKE 'H%' AS "true";
+SELECT 'hawkeye' NOT ILIKE 'H%' AS "false";
+
+SELECT 'hawkeye' ILIKE 'H%Eye' AS "true";
+SELECT 'hawkeye' NOT ILIKE 'H%Eye' AS "false";
+
+SELECT 'Hawkeye' ILIKE 'h%' AS "true";
+SELECT 'Hawkeye' NOT ILIKE 'h%' AS "false";
 
 --
 -- test implicit type conversion