B-A-BA tal, metal, tales
TAL consists of seven different commands (highest priority first): define, condition, repeat, content, replace, attributes, and omit-tag. Commands are attributes on HTML or XML tags, e.g. <div tal:content="article">Article goes here</div>
The expressions used in TAL are called TALES expressions. The simplest TALES expression is a path which references a value, e.g. page/body references the body property of the page object.
METAL is a macro language commonly used with TAL & TALES. METAL allows part of a template to be used as a macro in later parts of a template, or a separate template altogether.
source : http://www.owlfish.com/software/simpleTAL/tal-guide.html
