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<chapter id="functions">

<title>Functions and Operators</title>

<primary>pg_get_ruledef</primary>

</indexterm>

<indexterm>

<primary>pg_get_functiondef</primary>

</indexterm>

<indexterm>

<primary>pg_get_function_arguments</primary>

</indexterm>

<entry>decompile internal form of an expression, assuming that any Vars

in it refer to the relation indicated by the second parameter</entry>

</row>

<row>

<entry><literal><function>pg_get_functiondef</function>(<parameter>func_oid</parameter>)</literal></entry>

<entry><type>text</type></entry>

<entry>get definition of a function</entry>

</row>

<row>

<entry><literal><function>pg_get_function_arguments</function>(<parameter>func_oid</parameter>)</literal></entry>

<entry><type>text</type></entry>

</para>

<para>

<function>pg_get_functiondef</> returns a complete

<command>CREATE OR REPLACE FUNCTION</> statement for a function.

<function>pg_get_function_arguments</function> returns the argument list

of a function, in the form it would need to appear in within

<command>CREATE FUNCTION</>.

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</varlistentry>

<varlistentry>

<term><literal>\ef <replaceable class="parameter">function_description</replaceable> </literal></term>

<listitem>

<para>

This command fetches and edits the definition of the named function,

in the form of a <command>CREATE OR REPLACE FUNCTION</> command.

Editing is done in the same way as for <literal>\e</>.

After the editor exits, the updated command waits in the query buffer;

type semicolon or <literal>\g</> to send it, or <literal>\r</>

to cancel.

</para>

<para>

The target function can be specified by name alone, or by name

and arguments, for example <literal>foo(integer, text)</>.

The argument types must be given if there is more

than one function of the same name.

</para>

</listitem>

</varlistentry>

<varlistentry>

<term><literal>\echo <replaceable class="parameter">text</replaceable> [ ... ]</literal></term>

<listitem>