# Eval() and Action()

The eval() function evaluates an string and returns the result. For example,

> `eval("$Price*1.05")`

returns the value of price augmented by 5%.

The eval() function performs an action stored in a string.

> `action("$Total=$Price*1.05")`

changes the value of `$Total`.

action() and eval() are most frequently used in export templates, but may occasionally prove useful when a note must assemble a rule on the fly.