| Maintainer | hapytexeu+gh@gmail.com |
|---|---|
| Stability | experimental |
| Portability | POSIX |
| Safe Haskell | Safe-Inferred |
| Language | Haskell2010 |
Data.Pattern.Any
Description
The module exposes two QuasiQuoters named anypat and maypat that allow compiling separate patterns into a single (view) pattern that
will fire in case any of the patterns matches. If there are any variable names, it will match these. For the anypat it requires that all
variables occur in all patterns. For maypat that is not a requirement. For both QuasiQuoters, it is however required that the variables
have the same type in each pattern.
Synopsis
- anypat :: QuasiQuoter
- maypat :: QuasiQuoter
- rangepat :: QuasiQuoter
- patVars :: Pat -> [Name]
- patVars' :: Pat -> [Name] -> [Name]
- data RangeObj a
- = FromRange a
- | FromThenRange a a
- | FromToRange a a
- | FromThenToRange a a a
- rangeToList :: Enum a => RangeObj a -> [a]
- inRange :: Enum a => RangeObj a -> a -> Bool
Quasiquoters
Arguments
| :: QuasiQuoter | The quasiquoter that can be used as expression and pattern. |
A quasquoter to specify multiple patterns that will succeed if any of the patterns match. All patterns should have the same set of variables and these should have the same type, otherwise a variable would have two different types, and if a variable is absent in one of the patterns, the question is what to pass as value.
Arguments
| :: QuasiQuoter | The quasiquoter that can be used as expression and pattern. |
A quasiquoter to specify multiple patterns that will succeed if any of these patterns match. Patterns don't have to have the same variable names but if a variable is shared over the
different patterns, it should have the same type. In case a variable name does not appear in all patterns, it will be passed as a Maybe to the clause with Nothing if a pattern matched
without that variable name, and a Just if the (first) pattern that matched had such variable.
Arguments
| :: QuasiQuoter | The quasiquoter that can be used as expression and pattern. |
A QuasiQuoter to parse a range expression to a RangeObj. In case the QuasiQuoter is used for a pattern,
it compiles into a view pattern that will work if the element is a member of the RangeObj.
derive variable names names from patterns
Arguments
| :: Pat | The |
| -> [Name] | The list of variable names that is used to collect (fragments) of the pattern. |
Provides a list of variable names for a given Pattern. The list is not sorted. If the same variable name occurs multiple times (which does not make much sense), it will be listed multiple times.
Arguments
| :: Pat | The |
| -> [Name] | The list of remaining elements that is added as tail. |
| -> [Name] | The list of variable names that is used to collect (fragments) of the pattern. |
Provides a list of variable names for a given Pattern. The list is not sorted. If the same variable name occurs multiple times (which does not make much sense), it will be listed multiple times.
Range objects
A RangeObj that specifies a range with a start value and optionally a step value and end value.
Constructors
| FromRange a | A |
| FromThenRange a a | A |
| FromToRange a a | A |
| FromThenToRange a a a | A |
Arguments
| :: Enum a | |
| => RangeObj a | The |
| -> [a] | A list of items the |
Convert the RangeObj to a list of the values defined by the range.
Arguments
| :: Enum a | |
| => RangeObj a | The |
| -> a | The element for which we check the membership. |
| -> Bool |
Check if the given value is in the given RangeObj. This function has some caveats, especially with floating points or other Enum instances
where fromEnum and toEnum are no bijections. For example for floating points, `12.5` and `12.2` both map on the same item, as a result, the enum
will fail to work properly.