Convert createlang/droplang to use CREATE/DROP EXTENSION.

In createlang this is a one-line change.  In droplang there's a whole
lot of cruft that can be discarded since the extension mechanism now
manages removal of the language's support functions.

Also, add deprecation notices to these two programs' reference pages,
since per discussion we may toss them overboard altogether in a release
or two.

2 files changed, 31 insertions, 17 deletions

diff --git a/doc/src/sgml/ref/createlang.sgml b/doc/src/sgml/ref/createlang.sgml
index 36bd318e1de..0bc1976c15e 100644
--- a/doc/src/sgml/ref/createlang.sgml
+++ b/doc/src/sgml/ref/createlang.sgml
@@ -12,7 +12,7 @@ PostgreSQL documentation
 
  <refnamediv>
   <refname>createlang</refname>
-  <refpurpose>define a new <productname>PostgreSQL</productname> procedural language</refpurpose>
+  <refpurpose>install a <productname>PostgreSQL</productname> procedural language</refpurpose>
  </refnamediv>
 
  <indexterm zone="app-createlang">
@@ -40,12 +40,22 @@ PostgreSQL documentation
   <title>Description</title>
 
   <para>
-   <application>createlang</application> is a utility for adding a new
-   programming language to a <productname>PostgreSQL</productname> database.
+   <application>createlang</application> is a utility for adding a
+   procedural language to a <productname>PostgreSQL</productname> database.
+  </para>
+
+  <para>
    <application>createlang</application> is just a wrapper around the
-   <xref linkend="sql-createlanguage">
-   command.
+   <xref linkend="sql-createextension"> SQL command.
   </para>
+
+  <caution>
+   <para>
+    <application>createlang</application> is deprecated and may be removed
+    in a future <productname>PostgreSQL</productname> release.  Direct use
+    of the <command>CREATE EXTENSION</> command is recommended instead.
+   </para>
+  </caution>
  </refsect1>
 
 
@@ -60,8 +70,7 @@ PostgreSQL documentation
       <term><replaceable class="parameter">langname</replaceable></term>
       <listitem>
        <para>
-        Specifies the name of the procedural programming language to be
-        defined.
+        Specifies the name of the procedural language to be installed.
        </para>
       </listitem>
      </varlistentry>
@@ -273,6 +282,7 @@ PostgreSQL documentation
 
   <simplelist type="inline">
    <member><xref linkend="app-droplang"></member>
+   <member><xref linkend="sql-createextension"></member>
    <member><xref linkend="sql-createlanguage"></member>
   </simplelist>
  </refsect1>
diff --git a/doc/src/sgml/ref/droplang.sgml b/doc/src/sgml/ref/droplang.sgml
index c9d034a4c14..810c78e5215 100644
--- a/doc/src/sgml/ref/droplang.sgml
+++ b/doc/src/sgml/ref/droplang.sgml
@@ -42,19 +42,22 @@ PostgreSQL documentation
 
   <para>
    <application>droplang</application> is a utility for removing an
-   existing programming language from a
+   existing procedural language from a
    <productname>PostgreSQL</productname> database.
-   <application>droplang</application> can drop any procedural language,
-   even those not supplied by the <productname>PostgreSQL</> distribution.
   </para>
+
   <para>
-   Although backend programming languages can be removed directly using
-   several <acronym>SQL</acronym> commands, it is recommended to use
-   <application>droplang</application> because it performs a number
-   of checks and is much easier to use. See
-   <xref linkend="sql-droplanguage">
-   for more.
+   <application>droplang</application> is just a wrapper around the
+   <xref linkend="sql-dropextension"> SQL command.
   </para>
+
+  <caution>
+   <para>
+    <application>droplang</application> is deprecated and may be removed
+    in a future <productname>PostgreSQL</productname> release.  Direct use
+    of the <command>DROP EXTENSION</> command is recommended instead.
+   </para>
+  </caution>
  </refsect1>
 
 
@@ -69,7 +72,7 @@ PostgreSQL documentation
       <term><replaceable class="parameter">langname</replaceable></term>
       <listitem>
        <para>
-        Specifies the name of the backend programming language to be removed.
+        Specifies the name of the procedural language to be removed.
        </para>
       </listitem>
      </varlistentry>
@@ -277,6 +280,7 @@ PostgreSQL documentation
 
   <simplelist type="inline">
    <member><xref linkend="app-createlang"></member>
+   <member><xref linkend="sql-dropextension"></member>
    <member><xref linkend="sql-droplanguage"></member>
   </simplelist>
  </refsect1>