> For the complete documentation index, see [llms.txt](https://chaoses-ib.gitbook.io/directory-opus/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://chaoses-ib.gitbook.io/directory-opus/manual/evaluator/applicable_contexts/functions.md).

# Buttons and Functions

Functions (such as those you add to toolbar buttons or hotkeys) can use the evaluator in a number of ways:

* The [label](/directory-opus/manual/evaluator/applicable_contexts/functions/labels.md) can be dynamically generated using the **@label** modifier.
* The [icon](/directory-opus/manual/evaluator/applicable_contexts/functions/icons.md) can be dynamically modified using the **@icon** and related modifiers.
* The button [tooltip](/directory-opus/manual/evaluator/applicable_contexts/functions/tooltips.md) can be generated using an evaluation expression.
* Button [states](/directory-opus/manual/evaluator/applicable_contexts/functions/dynamic_state.md) like enabled/disabled, hidden/shown and checked/unchecked can be modified using the evaluator.
* [Conditional behavior](/directory-opus/manual/evaluator/applicable_contexts/functions/conditional_behavior.md) in buttons using **@if** and **@ifset** can be performed using the evaluator.
* The [**@eval**](/directory-opus/manual/evaluator/applicable_contexts/functions/evaluation_clauses.md) modifier lets you run a line of evaluator code as part of a function.
* The return value of an evaluator expression can be [inserted](/directory-opus/manual/evaluator/applicable_contexts/functions/insertion_code.md) into a command line using the `{= ... =}` code.
* The evaluator can be used to generate a [command line](/directory-opus/manual/evaluator/applicable_contexts/functions/commands.md) that's then executed as if it were part of the function.