Based on the php-smarty TextMate bundle

• smarty highlighting is present inside html tags enclosed by {literal}
• custom block functions (e.g. {textformat}{/textformat}) won't show in itemizer as a parent node

• highlighting for $smarty reserved variable and foreach/section variables (index, iteration etc.)
• auto-completion and highlighting for native variable modifiers
• mark invalid syntax?

Permission to copy, use, modify, sell and distribute this
software is granted. This software is provided "as is" without
express or implied warranty, and with no claim as to its
suitability for any purpose.