W3TPL/tags/let

About

 * Action: Assigns a value to a variable.
 * Options:
 * echo: replace the tag with the resulting value
 * index= treats name as an array, and specifies the element to use
 * name= name of variable to set
 * null: set the variable to NULL
 * oparse: parse the output (only has an effect if "echo" is present)
 * self: takes starting value from same variable, to allow unary operations