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concatMap :: Foldable t => (a -> [b]) -> t a -> [b]ghc-internal GHC.Internal.Data.List Map a function over all the elements of a container and concatenate the resulting lists.
Examples
Basic usage:>>> concatMap (take 3) [[1..], [10..], [100..], [1000..]] [1,2,3,10,11,12,100,101,102,1000,1001,1002]
>>> concatMap (take 3) (Just [1..]) [1,2,3]
concatMap :: (a -> [b]) -> [a] -> [b]ghc-internal GHC.Internal.Data.OldList Map a function returning a list over a list and concatenate the results. concatMap can be seen as the composition of concat and map.
concatMap f xs == (concat . map f) xs
Examples
>>> concatMap (\i -> [-i,i]) [] []
>>> concatMap (\i -> [-i, i]) [1, 2, 3] [-1,1,-2,2,-3,3]
>>> concatMap ('replicate' 3) [0, 2, 4] [0,0,0,2,2,2,4,4,4]fmapDefault :: Traversable t => (a -> b) -> t a -> t bghc-internal GHC.Internal.Data.Traversable This function may be used as a value for fmap in a Functor instance, provided that traverse is defined. (Using fmapDefault with a Traversable instance defined only by sequenceA will result in infinite recursion.)
fmapDefault f ≡ runIdentity . traverse (Identity . f)
foldMapDefault :: (Traversable t, Monoid m) => (a -> m) -> t a -> mghc-internal GHC.Internal.Data.Traversable This function may be used as a value for foldMap in a Foldable instance.
foldMapDefault f ≡ getConst . traverse (Const . f)
concatMap :: (a -> [b]) -> [a] -> [b]ghc-internal GHC.Internal.List Map a function returning a list over a list and concatenate the results. concatMap can be seen as the composition of concat and map.
concatMap f xs == (concat . map f) xs
Examples
>>> concatMap (\i -> [-i,i]) [] []
>>> concatMap (\i -> [-i, i]) [1, 2, 3] [-1,1,-2,2,-3,3]
>>> concatMap ('replicate' 3) [0, 2, 4] [0,0,0,2,2,2,4,4,4]contextGetFontMap :: (HasCallStack, MonadIO m, IsContext a) => a -> m (Maybe FontMap)gi-pango GI.Pango.Objects.Context Gets the PangoFontMap used to look up fonts for this context. Since: 1.6
contextSetFontMap :: (HasCallStack, MonadIO m, IsContext a, IsFontMap b) => a -> Maybe b -> m ()gi-pango GI.Pango.Objects.Context Sets the font map to be searched when fonts are looked-up in this context. This is only for internal use by Pango backends, a PangoContext obtained via one of the recommended methods should already have a suitable font map.
fontGetFontMap :: (HasCallStack, MonadIO m, IsFont a) => Maybe a -> m (Maybe FontMap)gi-pango GI.Pango.Objects.Font Gets the font map for which the font was created. Note that the font maintains a *weak* reference to the font map, so if all references to font map are dropped, the font map will be finalized even if there are fonts created with the font map that are still alive. In that case this function will return Nothing. It is the responsibility of the user to ensure that the font map is kept alive. In most uses this is not an issue as a PangoContext holds a reference to the font map. Since: 1.10
module GI.Pango.Objects.
FontMap A PangoFontMap represents the set of fonts available for a particular rendering system. This is a virtual object with implementations being specific to particular rendering systems.
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gi-pango GI.Pango.Objects.FontMap Memory-managed wrapper type.