= Known incompatibilities with Smarty 2 =

== Syntax ==

Smarty 3 API has a new syntax. Much of the Smarty 2 syntax is supported 

by a wrapper but deprecated. See the README that comes with Smarty 3 for more 

information.

The {$array|@mod} syntax has always been a bit confusing, where an "@" is required

to apply a modifier to an array instead of the individual elements. Normally you

always want the modifier to apply to the variable regardless of its type. In Smarty 3,

{$array|mod} and {$array|@mod} behave identical. It is safe to drop the "@" and the

modifier will still apply to the array. If you really want the modifier to apply to

each array element, you must loop the array in-template, or use a custom modifier that

supports array iteration. Most smarty functions already escape values where necessary

such as {html_options}

== PHP Version ==

Smarty 3 is PHP 5 only. It will not work with PHP 4.

== {php} Tag ==

The {php} tag is disabled by default. The use of {php} tags is

deprecated. It can be enabled with $smarty->allow_php_tag=true.

But if you scatter PHP code which belongs together into several

{php} tags it may not work any longer.

== Delimiters and whitespace ==

Delimiters surrounded by whitespace are no longer treated as Smarty tags.

Therefore, { foo } will not compile as a tag, you must use {foo}. This change

Makes Javascript/CSS easier to work with, eliminating the need for {literal}.

This can be disabled by setting $smarty->auto_literal = false;

== Unquoted Strings ==

Smarty 2 was a bit more forgiving (and ambiguous) when it comes to unquoted strings 

in parameters. Smarty3 is more restrictive. You can still pass strings without quotes 

so long as they contain no special characters. (anything outside of A-Za-z0-9_) 

For example filename strings must be quoted

<source lang="smarty">

{include file='path/foo.tpl'}

</source>

== Extending the Smarty class ==

Smarty 3 makes use of the __construct method for initialization. If you are extending 

the Smarty class, its constructor is not called implicitly if the your child class defines 

its own constructor. In order to run Smarty's constructor, a call to parent::__construct() 

within your child constructor is required. 

<source lang="php">

class MySmarty extends Smarty {

   function __construct() {

       parent::__construct();

       // your initialization code goes here

   }

}

</source>

== Autoloader ==

Smarty 3 does register its own autoloader with spl_autoload_register. If your code has 

an existing __autoload function then this function must be explicitly registered on 

the __autoload stack. See http://us3.php.net/manual/en/function.spl-autoload-register.php 

for further details.

== Plugin Filenames ==

Smarty 3 optionally supports the PHP spl_autoloader. The autoloader requires filenames 

to be lower case. Because of this, Smarty plugin file names must also be lowercase. 

In Smarty 2, mixed case file names did work.

== Scope of Special Smarty Variables ==

In Smarty 2 the special Smarty variables $smarty.section... and $smarty.foreach... 

had global scope. If you had loops with the same name in subtemplates you could accidentally 

overwrite values of parent template.

In Smarty 3 these special Smarty variable have only local scope in the template which 

is defining the loop. If you need their value in a subtemplate you have to pass them 

as parameter.

<source lang="smarty">

{include file='path/foo.tpl' index=$smarty.section.foo.index}

</source>

== SMARTY_RESOURCE_CHAR_SET ==

Smarty 3 sets the constant SMARTY_RESOURCE_CHAR_SET to utf-8 as default template charset. 

This is now used also on modifiers like escape as default charset. If your templates use 

other charsets make sure that you define the constant accordingly. Otherwise you may not 

get any output.

== newline at {if} tags ==

A \n was added to the compiled code of the {if},{else},{elseif},{/if} tags to get output of newlines as expected by the template source. 

If one of the {if} tags is at the line end you will now get a newline in the HTML output.

== trigger_error() ==

The API function trigger_error() has been removed because it did just map to PHP trigger_error.

However it's still included in the Smarty2 API wrapper.

== Smarty constants ==

The constants 

SMARTY_PHP_PASSTHRU

SMARTY_PHP_QUOTE

SMARTY_PHP_REMOVE

SMARTY_PHP_ALLOW

have been replaced with class constants

Smarty::PHP_PASSTHRU

Smarty::PHP_QUOTE

Smarty::PHP_REMOVE

Smarty::PHP_ALLOW