{eval}

{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.

Attributes

| Attribute Name | Required | Description | |----------------|----------|------------------------------------------------------| | var | Yes | Variable (or string) to evaluate | | assign | No | The template variable the output will be assigned to |

If you supply the assign attribute, the output of the {eval} function will be assigned to this template variable instead of being output to the template.

> Note > > - Evaluated variables are treated the same as templates. They follow > the same escapement and security features just as if they were > templates. > > - 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. > > - If the content to evaluate doesn't change often, or is used > repeatedly, consider using > {include file="string:{$template_code}"} instead. This may cache > the compiled state and thus doesn't have to run the (comparably > slow) compiler on every invocation.

Examples

The contents of the config file, setup.conf.

emphstart = <strong>
emphend = </strong>
title = Welcome to {$company}'s home page!
ErrorCity = You must supply a {#emphstart#}city{#emphend#}.
ErrorState = You must supply a {#emphstart#}state{#emphend#}.

Where the template is:

{config_load file='setup.conf'}

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

The above template will output:

This is the contents of foo.
Welcome to Foobar Pub & Grill's home page!
You must supply a <strong>city</strong>.
You must supply a <strong>state</strong>.

This outputs the server name (in uppercase) and IP. The assigned variable $str could be from a database query.

<?php
    $str = 'The server name is {$smarty.server.SERVER_NAME|upper} '
           .'at {$smarty.server.SERVER_ADDR}';
    $smarty->assign('foo',$str);

Where the template is:

{eval var=$foo}