GENERAL ------- Q: What is Smarty? A: Smarty is a template engine for PHP... but be aware this isn't just another PHP template engine. It's much more than that. Q: What's the difference between Smarty and other template engines? A: Most other template engines for PHP provide basic variable substitution and dynamic block functionality. Smarty takes a step further to be a "smart" template engine, adding features such as configuration files, template functions, variable modifiers (see the docs!) and making all of this functionality as easy as possible to use for both programmers and template designers. Smarty also compiles the templates into PHP scripts, eliminating the need to parse the templates on every invocation, making Smarty extremely scalable and managable for large application needs. Q: What do you mean "Compiled PHP Scripts" ? A: Smarty reads the template files and creates PHP scripts from them. Once these PHP scripts are created, Smarty executes these, never having to parse the template files again. If you change a template file, Smarty will recreate the PHP script for it. All this is done automatically by Smarty. Template designers never need to mess with the generated PHP scripts or even know of their existance. (NOTE: you can turn off this compile checking step in Smarty for increased performance.) Q: Why can't I just use APC (or Zend Cache)? A: Smarty and these cache solutions have nothing in common. What APC does is caches compiled bytecode of your PHP scripts in shared memory or in a file. This speeds up server response and saves the compilation step. Smarty creates PHP scripts (which APC will cache nicely) and also has it's own internal caching mechanism for the output of the template contents. For example, if you have a template that requires several database queries, Smarty can cache this output, saving the need to call the database every time. APC cannot help you here. Smarty and APC (or Zend Cache) actually complement each other nicely. If performance is of the utmost importance, we would recommend using one of these with any PHP application, using Smarty or not. Q: Is Smarty faster than ? A: This would mostly depend on the other template engine, but as a general rule of thumb: Without a PHP caching solution like APC or Zend Cache, Smarty is most likely as fast, or possibly slower. With APC, Smarty is mostly like as fast or much faster. The reason is this: Smarty generates PHP scripts from your templates. The more templates your application has, the more PHP scripts Smarty generates. This in turn requires more time for the PHP parser to compile the PHP scripts. With APC, this compilation step is cached. So as the complexity of the templates increase, the performance savings go up accordingly. Also, most other template solutions parse the template files on each invocation. The more complex the templates are, the longer they take to parse. Smarty has no need to parse template files, it only executes PHP scripts. We are working on a release of Smarty that will be noticably quicker even without the aid of a PHP script caching solution by minimizing the amount of PHP code that is compiled on each request. The above comparison assumes that you are not using Smarty's built-in ability to cache templates. If you are, that makes this comparison pretty useless since Smarty will basically be displaying static content instead of generating templates, which of course will be magnitudes faster. Q: Can I use Macromedia's Dreamweaver to edit my templates? A: Certainly. You might want to change your tag delimiters from {} to something that resembles valid HTML, like or <{ }> or something similar. This way the editor won't view the template tags as errors. Q: Do you have a mailing list? A: Yes. Subscribe by sending an e-mail to subscribe-smarty@lists.ispi.net. This is also archived at http://marc.theaimsgroup.com/ under www/smarty TROUBLESHOOTING --------------- Q: Smarty doesn't work. A: You must be using PHP 4.0.4pl1 or later to fix all known problems Smarty has with PHP. Read the BUGS file for more info. Q: I get the following error when running Smarty: Warning: Wrong parameter count for preg_replace() in Smarty.class.php on line 371 A: preg_replace had a parameter added in PHP 4.0.2 that Smarty requires. Upgrade to at least 4.0.4pl to fix all known PHP issues with Smarty. Q: I get the following error when running Smarty: Fatal error: Failed opening required 'PEAR.php' (include_path='') in Config_File.class.php on line 3 A: Smarty uses the PEAR libraries for some of its error handling routines. PEAR libraries come with the distribution of PHP. Be sure that the path to these libraries is included in your php include_path. Unix users check /usr/local/lib/php. Windows users check C:/php/pear. Q: I get this error when passing variables to {include}: Fatal error: Call to undefined function: get_defined_vars() in /path/to/Smarty/templates_c/index.tpl.php on line 8 A: get_defined_vars() was added to PHP 4.0.4. If you plan on passing variables to included templates, you will need PHP 4.0.4 or later. Q: I get PHP errors in my {if} tag logic. A: All conditional qualifiers must be separated by spaces. This syntax will not work: {if $name=="Wilma"} You must instead do this: {if $name == "Wilma"}. The reason for this is syntax ambiguity. Both "==" and "eq" are equivalent in the template parser, so something like {if $nameeq"Wilma"} wouldn't be parsable by the tokenizer. Q: I'm changing my php code and/or templates, and my results are not getting updated. A: This may be the result of your compile or cache settings. If you are changing your php code, your templates will not necessarily get recompiled to reflect the changes. Use $force_compile during develpment to avoid these situations. Also turn off caching during development when you aren't specifically testing it. You can also remove everything from your compile_dir and cache_dir and reload the page to be sure everything gets regenerated. Q: I'm running Windows 2000 and I get blank content. My compiled PHP files are also zero length. A: There seems to be a problem with some W2k machines and exclusive file locking. Comment out the flock() call in _write_file to get around this, although be aware this could possibly cause a problem with simultaneous writes to a file, especially with caching turned on.