Brick.Focus

This module provides a type and functions for handling focus rings of values.

This interface is experimental.

Documentation

data FocusRing n

A focus ring containing a sequence of resource names to focus and a currently-focused name.

focusRing :: [n] -> FocusRing n

Construct a focus ring from the list of resource names.

focusNext :: FocusRing n -> FocusRing n

Advance focus to the next value in the ring.

focusPrev :: FocusRing n -> FocusRing n

Advance focus to the previous value in the ring.

focusGetCurrent :: FocusRing n -> Maybe n

Get the currently-focused resource name from the ring. If the ring is emtpy, return Nothing.

focusSetCurrent :: Eq n => n -> FocusRing n -> FocusRing n

Set the currently-focused resource name in the ring, provided the name is in the ring. Otherwise return the ring unmodified.

focusRingLength :: FocusRing n -> Int

Get the size of the FocusRing.

focusRingToList :: FocusRing n -> [n]

Return all of the entries in the focus ring, starting with the currently-focused entry and wrapping around the ring.

For example, if a ring contains A, B, C, and D, and the current entry is B, the result will be [B, C, D, A].

focusRingCursor

Arguments

:: Eq n

=> (a -> FocusRing n)

The function used to get the focus ring out of your application state.

-> a

Your application state.

-> [CursorLocation n]

The list of available cursor positions.

-> Maybe (CursorLocation n)

The cursor position, if any, that matches the resource name currently focused by the FocusRing.

Cursor selection convenience function for use as an appChooseCursor value.

withFocusRing

Arguments

:: (Eq n, Named a n)

=> FocusRing n

The focus ring to use as the source of focus state.

-> (Bool -> a -> b)

A function that takes a value and its focus state.

-> a

The wiget state value that we need to check for focus.

-> b

The rest of the computation.

This function is a convenience function to look up a widget state value's resource name in a focus ring and set its focus setting according to the focus ring's state. This function determines whether a given widget state value is the focus of the ring and passes the resulting boolean to a rendering function, along with the state value (a), to produce whatever comes next (b).

Focus-aware widgets have rendering functions that should be usable with this combinator; see List and Edit.

focusRingModify :: (CList n -> CList n) -> FocusRing n -> FocusRing n

Modify the internal circular list structure of a focus ring directly. This function permits modification of the circular list using the rich Data.CircularList API.