XPath fixes:

 - Function renamed to "xpath".
 - Function is now strict, per discussion.
 - Return empty array in case when XPath expression detects nothing
   (previously, NULL was returned in such case), per discussion.
 - (bugfix) Work with fragments with prologue: select xpath('/a',
   '<?xml version="1.0"?><a /><b />'); // now XML datum is always wrapped
   with dummy <x>...</x>, XML prologue simply goes away (if any).
 - Some cleanup.

Nikolay Samokhvalov

Some code cleanup and documentation work by myself.

3 files changed, 30 insertions, 30 deletions

diff --git a/src/test/regress/expected/xml.out b/src/test/regress/expected/xml.out
index 20520d9760..cec9ea2944 100644
--- a/src/test/regress/expected/xml.out
+++ b/src/test/regress/expected/xml.out
@@ -402,37 +402,37 @@ SELECT table_name, view_definition FROM information_schema.views
 (9 rows)
 
 -- Text XPath expressions evaluation
-SELECT xmlpath('/value', data) FROM xmltest;
-       xmlpath        
+SELECT xpath('/value', data) FROM xmltest;
+        xpath         
 ----------------------
  {<value>one</value>}
  {<value>two</value>}
 (2 rows)
 
-SELECT xmlpath(NULL, NULL) IS NULL FROM xmltest;
+SELECT xpath(NULL, NULL) IS NULL FROM xmltest;
  ?column? 
 ----------
  t
  t
 (2 rows)
 
-SELECT xmlpath('', '<!-- error -->');
+SELECT xpath('', '<!-- error -->');
 ERROR:  empty XPath expression
-CONTEXT:  SQL function "xmlpath" statement 1
-SELECT xmlpath('//text()', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>');
-    xmlpath     
+CONTEXT:  SQL function "xpath" statement 1
+SELECT xpath('//text()', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>');
+     xpath      
 ----------------
  {"number one"}
 (1 row)
 
-SELECT xmlpath('//loc:piece/@id', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc'], ARRAY['http://127.0.0.1']]);
- xmlpath 
----------
+SELECT xpath('//loc:piece/@id', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
+ xpath 
+-------
  {1,2}
 (1 row)
 
-SELECT xmlpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');
-         xmlpath         
+SELECT xpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');
+          xpath          
 -------------------------
  {<b>two</b>,<b>etc</b>}
 (1 row)
diff --git a/src/test/regress/expected/xml_1.out b/src/test/regress/expected/xml_1.out
index e922107f8d..2bf9105770 100644
--- a/src/test/regress/expected/xml_1.out
+++ b/src/test/regress/expected/xml_1.out
@@ -326,29 +326,29 @@ SELECT table_name, view_definition FROM information_schema.views
 (2 rows)
 
 -- Text XPath expressions evaluation
-SELECT xmlpath('/value', data) FROM xmltest;
- xmlpath 
----------
+SELECT xpath('/value', data) FROM xmltest;
+ xpath 
+-------
 (0 rows)
 
-SELECT xmlpath(NULL, NULL) IS NULL FROM xmltest;
-ERROR:  unsupported XML feature
-DETAIL:  This functionality requires libxml support.
-HINT:  You need to re-compile PostgreSQL using --with-libxml.
-CONTEXT:  SQL function "xmlpath" statement 1
-SELECT xmlpath('', '<!-- error -->');
+SELECT xpath(NULL, NULL) IS NULL FROM xmltest;
+ ?column? 
+----------
+(0 rows)
+
+SELECT xpath('', '<!-- error -->');
 ERROR:  unsupported XML feature
 DETAIL:  This functionality requires libxml support.
 HINT:  You need to re-compile PostgreSQL using --with-libxml.
-SELECT xmlpath('//text()', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>');
+SELECT xpath('//text()', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>');
 ERROR:  unsupported XML feature
 DETAIL:  This functionality requires libxml support.
 HINT:  You need to re-compile PostgreSQL using --with-libxml.
-SELECT xmlpath('//loc:piece/@id', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc'], ARRAY['http://127.0.0.1']]);
+SELECT xpath('//loc:piece/@id', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
 ERROR:  unsupported XML feature
 DETAIL:  This functionality requires libxml support.
 HINT:  You need to re-compile PostgreSQL using --with-libxml.
-SELECT xmlpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');
+SELECT xpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');
 ERROR:  unsupported XML feature
 DETAIL:  This functionality requires libxml support.
 HINT:  You need to re-compile PostgreSQL using --with-libxml.
diff --git a/src/test/regress/sql/xml.sql b/src/test/regress/sql/xml.sql
index 1658a38036..2c9db299fd 100644
--- a/src/test/regress/sql/xml.sql
+++ b/src/test/regress/sql/xml.sql
@@ -147,9 +147,9 @@ SELECT table_name, view_definition FROM information_schema.views
 
 -- Text XPath expressions evaluation
 
-SELECT xmlpath('/value', data) FROM xmltest;
-SELECT xmlpath(NULL, NULL) IS NULL FROM xmltest;
-SELECT xmlpath('', '<!-- error -->');
-SELECT xmlpath('//text()', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>');
-SELECT xmlpath('//loc:piece/@id', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc'], ARRAY['http://127.0.0.1']]);
-SELECT xmlpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');
+SELECT xpath('/value', data) FROM xmltest;
+SELECT xpath(NULL, NULL) IS NULL FROM xmltest;
+SELECT xpath('', '<!-- error -->');
+SELECT xpath('//text()', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>');
+SELECT xpath('//loc:piece/@id', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
+SELECT xpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');