Data.Pattern.Any

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.

Quasiquoters

anypat

Arguments

:: QuasiQuoter

The quasiquoter that can be used as 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.

maypat

Arguments

:: QuasiQuoter

The quasiquoter that can be used as 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.

derive variable names names from patterns

patVars

Arguments

:: Pat

The Pattern to inspect.

-> [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.

patVars'

Arguments

:: Pat

The Pattern to inspect.

-> [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.