| Safe Haskell | None |
|---|
Control.PatternArrows
Description
Arrows for Pretty Printing
- newtype Pattern u a b = Pattern {
- runPattern :: Kleisli (StateT u Maybe) a b
- pattern :: Pattern u a b -> u -> a -> Maybe b
- mkPattern :: (a -> Maybe b) -> Pattern u a b
- mkPattern' :: (a -> StateT u Maybe b) -> Pattern u a b
- chainl :: Pattern u a (a, a) -> (r -> r -> r) -> Pattern u a r -> Pattern u a r
- chainr :: Pattern u a (a, a) -> (r -> r -> r) -> Pattern u a r -> Pattern u a r
- wrap :: Pattern u a (s, a) -> (s -> r -> r) -> Pattern u a r -> Pattern u a r
- split :: Pattern u a (s, t) -> (s -> t -> r) -> Pattern u a r
- data OperatorTable u a r = OperatorTable {
- runOperatorTable :: [[Operator u a r]]
- data Operator u a r where
- buildPrettyPrinter :: OperatorTable u a r -> Pattern u a r -> Pattern u a r
Documentation
A first-order pattern match
A pattern is a Kleisli arrow for the StateT Maybe monad. That is, patterns can fail, and can carry user-defined state.
Constructors
| Pattern | |
Fields
| |
pattern :: Pattern u a b -> u -> a -> Maybe bSource
Run a pattern with an input and initial user state
Returns Nothing if the pattern fails to match
mkPattern' :: (a -> StateT u Maybe b) -> Pattern u a bSource
Construct a pattern from a stateful function
chainl :: Pattern u a (a, a) -> (r -> r -> r) -> Pattern u a r -> Pattern u a rSource
Construct a pattern which recursively matches on the left-hand-side
chainr :: Pattern u a (a, a) -> (r -> r -> r) -> Pattern u a r -> Pattern u a rSource
Construct a pattern which recursively matches on the right-hand side
wrap :: Pattern u a (s, a) -> (s -> r -> r) -> Pattern u a r -> Pattern u a rSource
Construct a pattern which recursively matches on one-side of a tuple
split :: Pattern u a (s, t) -> (s -> t -> r) -> Pattern u a rSource
Construct a pattern which matches a part of a tuple
data OperatorTable u a r Source
A table of operators
Constructors
| OperatorTable | |
Fields
| |
data Operator u a r whereSource
An operator:
AssocL- A left-associative operator
AssocR- A right-associative operator
Wrap- A prefix-like or postfix-like operator
Split- A prefix-like or postfix-like operator which does not recurse into its operand
buildPrettyPrinter :: OperatorTable u a r -> Pattern u a r -> Pattern u a rSource
Build a pretty printer from an operator table and an indecomposable pattern