smarty/docs/en/designers/language-custom-functions/language-function-eval.xml

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		<sect1 id="language.function.eval">
			<title>eval</title>
            <informaltable frame="all">
                <tgroup cols="5">
                <colspec colname="param" align="center" />
                <colspec colname="type" align="center" />
                <colspec colname="required" align="center" />
                <colspec colname="default" align="center" />
                <colspec colname="desc" />
                <thead>
                    <row>
                        <entry>Attribute Name</entry>
                        <entry>Type</entry>
                        <entry>Required</entry>
                        <entry>Default</entry>
                        <entry>Description</entry>
                    </row>
                </thead>
                <tbody>
                    <row>
                        <entry>var</entry>
                        <entry>mixed</entry>
                        <entry>Yes</entry>
                        <entry><emphasis>n/a</emphasis></entry>
                        <entry>variable (or string) to evaluate</entry>
                    </row>
                    <row>
                        <entry>assign</entry>
                        <entry>string</entry>
                        <entry>No</entry>
                        <entry><emphasis>n/a</emphasis></entry>
                        <entry>the template variable the output will be assigned
						to</entry>
                    </row>
                </tbody>
                </tgroup>
            </informaltable>
			<para>
			eval is used to evaluate a variable as a template. This can be used
			for things like embedding template tags/variables into variables or
			tags/variables into config file variables.
			</para>
			<para>
			If you supply the special "assign" attribute, the output of the
			eval function will be assigned to this template variable instead of
			being output to the template.
			</para>
			<note>
			<title>Technical Note</title>
			<para>
			Evaluated variables are treated the same as templates. They follow
			the same escapement and security features just as if they were
			templates.
			</para>
			</note>
			<note>
			<title>Technical Note</title>
			<para>
			Evaluated variables are compiled on every invocation, the compiled
			versions are not saved! However if you have caching enabled, the
			output will be cached with the rest of the template.
			</para>
			</note>
<example>
<title>eval</title>
<programlisting>
setup.conf
----------

emphstart = &lt;b&gt;
emphend = &lt;/b&gt;
title = Welcome to {$company}'s home page!
ErrorCity = You must supply a {#emphstart#}city{#emphend#}.
ErrorState = You must supply a {#emphstart#}state{#emphend#}.


index.tpl
---------

{config_load file="setup.conf"}

{eval var=$foo}
{eval var=#title#}
{eval var=#ErrorCity#}
{eval var=#ErrorState# assign="state_error"}
{$state_error}

OUTPUT:

This is the contents of foo.
Welcome to Foobar Pub &amp; Grill's home page!
You must supply a &lt;b&gt;city&lt;/b&gt;.
You must supply a &lt;b&gt;state&lt;/b&gt;.

</programlisting>
</example>
</sect1>
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