v7-psql-df-pick-function-by-type.patch

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index c1451c1672..db987c14bb 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1567,7 +1567,7 @@ testdb=>
 
 
       <varlistentry>
-        <term><literal>\df[anptwS+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <term><literal>\df[anptwS+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> [ <replaceable class="parameter">arg_pattern</replaceable> ... ] ]</literal></term>
 
         <listitem>
         <para>
@@ -1580,6 +1580,9 @@ testdb=&gt;
         If <replaceable
         class="parameter">pattern</replaceable> is specified, only
         functions whose names match the pattern are shown.
+        Any additional arguments are type-name patterns, which are matched
+        to the type names of the first, second, and so on arguments of the
+        function.
         By default, only user-created
         objects are shown; supply a pattern or the <literal>S</literal>
         modifier to include system objects.
@@ -1589,14 +1592,6 @@ testdb=&gt;
         language, source code and description.
         </para>
 
-        <tip>
-        <para>
-        To look up functions taking arguments or returning values of a specific
-        data type, use your pager's search capability to scroll through the
-        <literal>\df</literal> output.
-        </para>
-        </tip>
-
         </listitem>
       </varlistentry>
 
@@ -4986,6 +4981,22 @@ second | four
 </programlisting>
   </para>
 
+  <para>
+   Here is an example of using the <command>\df</command> command to
+   find only functions with names matching <literal>int*pl</literal>
+   and whose second argument is of type <type>bigint</type>:
+<programlisting>
+testdb=&gt; <userinput>\df int*pl * bigint</userinput>
+                          List of functions
+   Schema   |  Name   | Result data type | Argument data types | Type
+------------+---------+------------------+---------------------+------
+ pg_catalog | int28pl | bigint           | smallint, bigint    | func
+ pg_catalog | int48pl | bigint           | integer, bigint     | func
+ pg_catalog | int8pl  | bigint           | bigint, bigint      | func
+(3 rows)
+</programlisting>
+  </para>
+
   <para>
   When suitable, query results can be shown in a crosstab representation
   with the <command>\crosstabview</command> command:
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index e04ccc5b62..8d2c8e85df 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -72,6 +72,9 @@ static backslashResult exec_command_copyright(PsqlScanState scan_state, bool act
 static backslashResult exec_command_crosstabview(PsqlScanState scan_state, bool active_branch);
 static backslashResult exec_command_d(PsqlScanState scan_state, bool active_branch,
 									  const char *cmd);
+static bool exec_command_df(PsqlScanState scan_state, const char *cmd,
+							const char *func_pattern,
+							bool show_verbose, bool show_system);
 static backslashResult exec_command_edit(PsqlScanState scan_state, bool active_branch,
 										 PQExpBuffer query_buf, PQExpBuffer previous_buf);
 static backslashResult exec_command_ef_ev(PsqlScanState scan_state, bool active_branch,
@@ -790,7 +793,8 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 					case 'p':
 					case 't':
 					case 'w':
-						success = describeFunctions(&cmd[2], pattern, show_verbose, show_system);
+						success = exec_command_df(scan_state, cmd, pattern,
+												  show_verbose, show_system);
 						break;
 					default:
 						status = PSQL_CMD_UNKNOWN;
@@ -951,6 +955,40 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 	return status;
 }
 
+/* \df and related commands; messy enough to split out of exec_command_d */
+static bool
+exec_command_df(PsqlScanState scan_state, const char *cmd,
+				const char *func_pattern,
+				bool show_verbose, bool show_system)
+{
+	bool		success;
+	char	   *arg_patterns[FUNC_MAX_ARGS];
+	int			num_arg_patterns = 0;
+
+	/* Collect argument-type patterns too */
+	if (func_pattern)			/* otherwise it was just \df */
+	{
+		char	   *ap;
+
+		while ((ap = psql_scan_slash_option(scan_state,
+											OT_NORMAL, NULL, true)) != NULL)
+		{
+			arg_patterns[num_arg_patterns++] = ap;
+			if (num_arg_patterns >= FUNC_MAX_ARGS)
+				break;			/* protect limited-size array */
+		}
+	}
+
+	success = describeFunctions(&cmd[2], func_pattern,
+								arg_patterns, num_arg_patterns,
+								show_verbose, show_system);
+
+	while (--num_arg_patterns >= 0)
+		free(arg_patterns[num_arg_patterns]);
+
+	return success;
+}
+
 /*
  * \e or \edit -- edit the current query buffer, or edit a file and
  * make it the query buffer
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 440249ff69..d31cdac3a7 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -312,7 +312,9 @@ describeTablespaces(const char *pattern, bool verbose)
  * and you can mix and match these in any order.
  */
 bool
-describeFunctions(const char *functypes, const char *pattern, bool verbose, bool showSystem)
+describeFunctions(const char *functypes, const char *func_pattern,
+				  char **arg_patterns, int num_arg_patterns,
+				  bool verbose, bool showSystem)
 {
 	bool		showAggregate = strchr(functypes, 'a') != NULL;
 	bool		showNormal = strchr(functypes, 'n') != NULL;
@@ -517,6 +519,14 @@ describeFunctions(const char *functypes, const char *pattern, bool verbose, bool
 						 "\nFROM pg_catalog.pg_proc p"
 						 "\n     LEFT JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace\n");
 
+	for (int i = 0; i < num_arg_patterns; i++)
+	{
+		appendPQExpBuffer(&buf,
+						  "     LEFT JOIN pg_catalog.pg_type t%d ON t%d.oid = p.proargtypes[%d]\n"
+						  "     LEFT JOIN pg_catalog.pg_namespace nt%d ON nt%d.oid = t%d.typnamespace\n",
+						  i, i, i, i, i, i);
+	}
+
 	if (verbose)
 		appendPQExpBufferStr(&buf,
 							 "     LEFT JOIN pg_catalog.pg_language l ON l.oid = p.prolang\n");
@@ -622,11 +632,32 @@ describeFunctions(const char *functypes, const char *pattern, bool verbose, bool
 		appendPQExpBufferStr(&buf, "      )\n");
 	}
 
-	processSQLNamePattern(pset.db, &buf, pattern, have_where, false,
+	processSQLNamePattern(pset.db, &buf, func_pattern, have_where, false,
 						  "n.nspname", "p.proname", NULL,
 						  "pg_catalog.pg_function_is_visible(p.oid)");
 
-	if (!showSystem && !pattern)
+	for (int i = 0; i < num_arg_patterns; i++)
+	{
+		/*
+		 * Match type-name patterns against either internal or external name,
+		 * like \dT.  Unlike \dT, there seems no reason to discriminate
+		 * against arrays or composite types.
+		 */
+		char		nspname[64];
+		char		typname[64];
+		char		ft[64];
+		char		tiv[64];
+
+		snprintf(nspname, sizeof(nspname), "tn%d.nspname", i);
+		snprintf(typname, sizeof(typname), "t%d.typname", i);
+		snprintf(ft, sizeof(ft), "pg_catalog.format_type(t%d.oid, NULL)", i);
+		snprintf(tiv, sizeof(tiv), "pg_catalog.pg_type_is_visible(t%d.oid)", i);
+		processSQLNamePattern(pset.db, &buf, arg_patterns[i],
+							  true, false,
+							  nspname, typname, ft, tiv);
+	}
+
+	if (!showSystem && !func_pattern)
 		appendPQExpBufferStr(&buf, "      AND n.nspname <> 'pg_catalog'\n"
 							 "      AND n.nspname <> 'information_schema'\n");
 
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index 39856a0c7e..01deed6799 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -19,7 +19,9 @@ extern bool describeAccessMethods(const char *pattern, bool verbose);
 extern bool describeTablespaces(const char *pattern, bool verbose);
 
 /* \df, \dfa, \dfn, \dft, \dfw, etc. */
-extern bool describeFunctions(const char *functypes, const char *pattern, bool verbose, bool showSystem);
+extern bool describeFunctions(const char *functypes, const char *func_pattern,
+							  char **arg_patterns, int num_arg_patterns,
+							  bool verbose, bool showSystem);
 
 /* \dT */
 extern bool describeTypes(const char *pattern, bool verbose, bool showSystem);
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index ac9a89a889..46e068cd7c 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -166,7 +166,7 @@ slashUsage(unsigned short int pager)
 	 * Use "psql --help=commands | wc" to count correctly.  It's okay to count
 	 * the USE_READLINE line even in builds without that.
 	 */
-	output = PageOutput(133, pager ? &(pset.popt.topt) : NULL);
+	output = PageOutput(135, pager ? &(pset.popt.topt) : NULL);
 
 	fprintf(output, _("General\n"));
 	fprintf(output, _("  \\copyright             show PostgreSQL usage and distribution terms\n"));
@@ -240,7 +240,8 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\des[+] [PATTERN]      list foreign servers\n"));
 	fprintf(output, _("  \\deu[+] [PATTERN]      list user mappings\n"));
 	fprintf(output, _("  \\dew[+] [PATTERN]      list foreign-data wrappers\n"));
-	fprintf(output, _("  \\df[anptw][S+] [PATRN] list [only agg/normal/procedures/trigger/window] functions\n"));
+	fprintf(output, _("  \\df[anptw][S+] [FUNCPTRN [TYPEPTRN ...]]\n"));
+	fprintf(output, _("                         list [only agg/normal/procedure/trigger/window] functions\n"));
 	fprintf(output, _("  \\dF[+]  [PATTERN]      list text search configurations\n"));
 	fprintf(output, _("  \\dFd[+] [PATTERN]      list text search dictionaries\n"));
 	fprintf(output, _("  \\dFp[+] [PATTERN]      list text search parsers\n"));
diff --git a/src/fe_utils/string_utils.c b/src/fe_utils/string_utils.c
index 9a1ea9ab98..5b206c7481 100644
--- a/src/fe_utils/string_utils.c
+++ b/src/fe_utils/string_utils.c
@@ -1062,10 +1062,16 @@ patternToSQLRegex(int encoding, PQExpBuffer dbnamebuf, PQExpBuffer schemabuf,
 			 * regexp errors.  Outside quotes, however, let them pass through
 			 * as-is; this lets knowledgeable users build regexp expressions
 			 * that are more powerful than shell-style patterns.
+			 *
+			 * As an exception to that, though, always quote "[]", as that's
+			 * much more likely to be an attempt to write an array type name
+			 * than it is to be the start of a regexp bracket expression.
 			 */
 			if ((inquotes || force_escape) &&
 				strchr("|*+?()[]{}.^$\\", ch))
 				appendPQExpBufferChar(curbuf, '\\');
+			else if (ch == '[' && cp[1] == ']')
+				appendPQExpBufferChar(curbuf, '\\');
 			i = PQmblen(cp, encoding);
 			while (i-- && *cp)
 			{
diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index 9a51940530..3135b2ab4b 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -5078,6 +5078,78 @@ List of access methods
  hash  | uuid_ops        | uuid                 | uuid                  |      2 | uuid_hash_extended
 (5 rows)
 
+-- check \df with argument specifications
+\df *sqrt
+                             List of functions
+   Schema   |     Name     | Result data type | Argument data types | Type 
+------------+--------------+------------------+---------------------+------
+ pg_catalog | dsqrt        | double precision | double precision    | func
+ pg_catalog | numeric_sqrt | numeric          | numeric             | func
+ pg_catalog | sqrt         | double precision | double precision    | func
+ pg_catalog | sqrt         | numeric          | numeric             | func
+(4 rows)
+
+\df *sqrt num*
+                             List of functions
+   Schema   |     Name     | Result data type | Argument data types | Type 
+------------+--------------+------------------+---------------------+------
+ pg_catalog | numeric_sqrt | numeric          | numeric             | func
+ pg_catalog | sqrt         | numeric          | numeric             | func
+(2 rows)
+
+\df int*pl
+                            List of functions
+   Schema   |    Name     | Result data type | Argument data types | Type 
+------------+-------------+------------------+---------------------+------
+ pg_catalog | int24pl     | integer          | smallint, integer   | func
+ pg_catalog | int28pl     | bigint           | smallint, bigint    | func
+ pg_catalog | int2pl      | smallint         | smallint, smallint  | func
+ pg_catalog | int42pl     | integer          | integer, smallint   | func
+ pg_catalog | int48pl     | bigint           | integer, bigint     | func
+ pg_catalog | int4pl      | integer          | integer, integer    | func
+ pg_catalog | int82pl     | bigint           | bigint, smallint    | func
+ pg_catalog | int84pl     | bigint           | bigint, integer     | func
+ pg_catalog | int8pl      | bigint           | bigint, bigint      | func
+ pg_catalog | interval_pl | interval         | interval, interval  | func
+(10 rows)
+
+\df int*pl int4
+                          List of functions
+   Schema   |  Name   | Result data type | Argument data types | Type 
+------------+---------+------------------+---------------------+------
+ pg_catalog | int42pl | integer          | integer, smallint   | func
+ pg_catalog | int48pl | bigint           | integer, bigint     | func
+ pg_catalog | int4pl  | integer          | integer, integer    | func
+(3 rows)
+
+\df int*pl * int8
+                          List of functions
+   Schema   |  Name   | Result data type | Argument data types | Type 
+------------+---------+------------------+---------------------+------
+ pg_catalog | int28pl | bigint           | smallint, bigint    | func
+ pg_catalog | int48pl | bigint           | integer, bigint     | func
+ pg_catalog | int8pl  | bigint           | bigint, bigint      | func
+(3 rows)
+
+\df acl* aclitem[]
+                                                                    List of functions
+   Schema   |    Name     | Result data type |                                        Argument data types                                         | Type 
+------------+-------------+------------------+----------------------------------------------------------------------------------------------------+------
+ pg_catalog | aclcontains | boolean          | aclitem[], aclitem                                                                                 | func
+ pg_catalog | aclexplode  | SETOF record     | acl aclitem[], OUT grantor oid, OUT grantee oid, OUT privilege_type text, OUT is_grantable boolean | func
+ pg_catalog | aclinsert   | aclitem[]        | aclitem[], aclitem                                                                                 | func
+ pg_catalog | aclremove   | aclitem[]        | aclitem[], aclitem                                                                                 | func
+(4 rows)
+
+\dfa bit* small*
+                          List of functions
+   Schema   |  Name   | Result data type | Argument data types | Type 
+------------+---------+------------------+---------------------+------
+ pg_catalog | bit_and | smallint         | smallint            | agg
+ pg_catalog | bit_or  | smallint         | smallint            | agg
+ pg_catalog | bit_xor | smallint         | smallint            | agg
+(3 rows)
+
 --
 -- combined queries
 --
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index bf06bb87b5..06b470aa8d 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -1229,6 +1229,15 @@ drop role regress_partitioning_role;
 \dAp+ btree float_ops
 \dAp * pg_catalog.uuid_ops
 
+-- check \df with argument specifications
+\df *sqrt
+\df *sqrt num*
+\df int*pl
+\df int*pl int4
+\df int*pl * int8
+\df acl* aclitem[]
+\dfa bit* small*
+
 --
 -- combined queries
 --