Safe Haskell	None
Language	Haskell2010

Brick.AttrMap

Contents

Construction
Inspection
Finding attributes from names
Manipulating attribute maps

Description

This module provides types and functions for managing an attribute map which maps attribute names (AttrName) to attributes (Attr). This module is designed to be used with the OverloadedStrings language extension to permit easy construction of AttrName values and you should also use mappend (<>) to combine names.

Attribute maps work by mapping hierarchical attribute names to attributes and inheriting parent names' attributes when child names specify partial attributes. Hierarchical names are created with mappend:

let n = attrName "parent" <> attrName "child"

Attribute names are mapped to attributes, but some attributes may be partial (specify only a foreground or background color). When attribute name lookups occur, the attribute corresponding to a more specific name ('parent <> child' as above) is sucessively merged with the parent attribute (parent as above) all the way to the "root" of the attribute map, the map's default attribute. In this way, more specific attributes inherit what they don't specify from more general attributes in the same hierarchy. This allows more modularity and less repetition in specifying how elements of your user interface take on different attributes.

Synopsis

data AttrMap
data AttrName
attrMap :: Attr -> [(AttrName, Attr)] -> AttrMap
forceAttrMap :: Attr -> AttrMap
attrName :: String -> AttrName
attrNameComponents :: AttrName -> [String]
attrMapLookup :: AttrName -> AttrMap -> Attr
setDefaultAttr :: Attr -> AttrMap -> AttrMap
getDefaultAttr :: AttrMap -> Attr
applyAttrMappings :: [(AttrName, Attr)] -> AttrMap -> AttrMap
mergeWithDefault :: Attr -> AttrMap -> Attr
mapAttrName :: AttrName -> AttrName -> AttrMap -> AttrMap
mapAttrNames :: [(AttrName, AttrName)] -> AttrMap -> AttrMap

Documentation

data AttrMap Source #

An attribute map which maps AttrName values to Attr values.

Instances

Show AttrMap Source #
Instance details Defined in Brick.AttrMap Methods showsPrec :: Int -> AttrMap -> ShowS # show :: AttrMap -> String # showList :: [AttrMap] -> ShowS #
Generic AttrMap Source #
Instance details Defined in Brick.AttrMap Associated Types type Rep AttrMap :: Type -> Type # Methods from :: AttrMap -> Rep AttrMap x # to :: Rep AttrMap x -> AttrMap #
NFData AttrMap Source #
Instance details Defined in Brick.AttrMap Methods rnf :: AttrMap -> () #
type Rep AttrMap Source #
Instance details Defined in Brick.AttrMap type Rep AttrMap = D1 (MetaData "AttrMap" "Brick.AttrMap" "brick-0.49-2yaIfapxp1L2Hh33OZcwJh" False) (C1 (MetaCons "AttrMap" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 Attr) :*: S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (Map AttrName Attr))) :+: C1 (MetaCons "ForceAttr" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 Attr)))

data AttrName Source #

An attribute name. Attribute names are hierarchical; use mappend (<>) to assemble them. Hierarchy in an attribute name is used to represent increasing levels of specificity in referring to the attribute you want to use for a visual element, with names to the left being general and names to the right being more specific. For example:

"window" <> "border"
"window" <> "title"
"header" <> "clock" <> "seconds"

Instances

Eq AttrName Source #
Instance details Defined in Brick.AttrMap Methods (==) :: AttrName -> AttrName -> Bool # (/=) :: AttrName -> AttrName -> Bool #
Ord AttrName Source #
Instance details Defined in Brick.AttrMap Methods compare :: AttrName -> AttrName -> Ordering # (<) :: AttrName -> AttrName -> Bool # (<=) :: AttrName -> AttrName -> Bool # (>) :: AttrName -> AttrName -> Bool # (>=) :: AttrName -> AttrName -> Bool # max :: AttrName -> AttrName -> AttrName # min :: AttrName -> AttrName -> AttrName #
Read AttrName Source #
Instance details Defined in Brick.AttrMap Methods readsPrec :: Int -> ReadS AttrName # readList :: ReadS [AttrName] # readPrec :: ReadPrec AttrName # readListPrec :: ReadPrec [AttrName] #
Show AttrName Source #
Instance details Defined in Brick.AttrMap Methods showsPrec :: Int -> AttrName -> ShowS # show :: AttrName -> String # showList :: [AttrName] -> ShowS #
IsString AttrName Source #
Instance details Defined in Brick.AttrMap Methods fromString :: String -> AttrName #
Generic AttrName Source #
Instance details Defined in Brick.AttrMap Associated Types type Rep AttrName :: Type -> Type # Methods from :: AttrName -> Rep AttrName x # to :: Rep AttrName x -> AttrName #
Semigroup AttrName Source #
Instance details Defined in Brick.AttrMap Methods (<>) :: AttrName -> AttrName -> AttrName # sconcat :: NonEmpty AttrName -> AttrName # stimes :: Integral b => b -> AttrName -> AttrName #
Monoid AttrName Source #
Instance details Defined in Brick.AttrMap Methods mempty :: AttrName # mappend :: AttrName -> AttrName -> AttrName # mconcat :: [AttrName] -> AttrName #
NFData AttrName Source #
Instance details Defined in Brick.AttrMap Methods rnf :: AttrName -> () #
GetAttr AttrName Source #
Instance details Defined in Brick.Markup Methods getAttr :: AttrName -> RenderM n Attr Source #
type Rep AttrName Source #
Instance details Defined in Brick.AttrMap type Rep AttrName = D1 (MetaData "AttrName" "Brick.AttrMap" "brick-0.49-2yaIfapxp1L2Hh33OZcwJh" False) (C1 (MetaCons "AttrName" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 [String])))

Construction

attrMap Source #

Arguments

:: Attr	The map's default attribute to be returned when a name lookup fails, and the attribute that will be merged with successful lookups.
-> [(AttrName, Attr)]	The map's initial contents.
-> AttrMap

Create an attribute map.

forceAttrMap :: Attr -> AttrMap Source #

Create an attribute map in which all lookups map to the same attribute.

attrName :: String -> AttrName Source #

Create an attribute name from a string.

Inspection

attrNameComponents :: AttrName -> [String] Source #

Get the components of an attribute name.

Finding attributes from names

attrMapLookup :: AttrName -> AttrMap -> Attr Source #

Look up the specified attribute name in the map. Map lookups proceed as follows. If the attribute map is forcing all lookups to a specific attribute, that attribute is returned. If the attribute name is empty, the map's default attribute is returned. If the attribute name is non-empty, very subsequence of names from the specified name are used to perform a lookup, and the results are combined as in mergeWithDefault, with more specific results taking precedence over less specific ones.

For example:

attrMapLookup ("foo" <> "bar") (attrMap a []) == a
attrMapLookup ("foo" <> "bar") (attrMap (bg blue) [("foo" <> "bar", fg red)]) == red `on` blue
attrMapLookup ("foo" <> "bar") (attrMap (bg blue) [("foo" <> "bar", red on cyan)]) == red `on` cyan
attrMapLookup ("foo" <> "bar") (attrMap (bg blue) [("foo" <> "bar", fg red), ("foo", bg cyan)]) == red `on` cyan
attrMapLookup ("foo" <> "bar") (attrMap (bg blue) [("foo", fg red)]) == red `on` blue

Manipulating attribute maps

setDefaultAttr :: Attr -> AttrMap -> AttrMap Source #

Set the default attribute value in an attribute map.

getDefaultAttr :: AttrMap -> Attr Source #

Get the default attribute value in an attribute map.

applyAttrMappings :: [(AttrName, Attr)] -> AttrMap -> AttrMap Source #

Insert a set of attribute mappings to an attribute map.

mergeWithDefault :: Attr -> AttrMap -> Attr Source #

Given an attribute and a map, merge the attribute with the map's default attribute. If the map is forcing all lookups to a specific attribute, the forced attribute is returned without merging it with the one specified here. Otherwise the attribute given here is merged with the attribute map's default attribute in that any aspect of the specified attribute that is not provided falls back to the map default. For example,

mergeWithDefault (fg blue) $ attrMap (bg red) []

returns

blue `on` red

mapAttrName :: AttrName -> AttrName -> AttrMap -> AttrMap Source #

Update an attribute map such that a lookup of ontoName returns the attribute value specified by fromName. This is useful for composite widgets with specific attribute names mapping those names to the sub-widget's expected name when calling that sub-widget's rendering function. See the ProgressBarDemo for an example usage, and overrideAttr for an alternate syntax.

mapAttrNames :: [(AttrName, AttrName)] -> AttrMap -> AttrMap Source #

Map several attributes to return the value associated with an alternate name. Applies mapAttrName across a list of mappings.