:: a -> Maybe a -> a -package:yesod-paginator -package:loc -package:type-hint package:hledger

The fromMaybe function takes a default value and a Maybe value. If the Maybe is Nothing, it returns the default value; otherwise, it returns the value contained in the Maybe.

Examples

Basic usage:

>>> fromMaybe "" (Just "Hello, World!")
"Hello, World!"

>>> fromMaybe "" Nothing
""

Read an integer from a string using readMaybe. If we fail to parse an integer, we want to return 0 by default:

>>> import Text.Read ( readMaybe )

>>> fromMaybe 0 (readMaybe "5")
5

>>> fromMaybe 0 (readMaybe "")
0

An alternative name for fromMaybe, to fit the naming scheme of this package. Generally using fromMaybe directly would be considered better style.

Replace all locations in the input with the same value. The default definition is fmap . const, but this may be overridden with a more efficient version.