Patterns

This module describes the patterns supported by Relapse.

It also contains some simple functions for the map of references that a Relapse grammar consists of.

Finally it also contains some very simple pattern functions.

Documentation

data Pattern

Pattern recursively describes a Relapse Pattern.

Constructors

Empty

ZAny

Node (Expr Bool) Pattern

Or Pattern Pattern

And Pattern Pattern

Not Pattern

Concat Pattern Pattern

Interleave Pattern Pattern

ZeroOrMore Pattern

Optional Pattern

Contains Pattern

Reference String

Instances

Eq Pattern

Methods

(==) :: Pattern -> Pattern -> Bool

(/=) :: Pattern -> Pattern -> Bool

Ord Pattern

Methods

compare :: Pattern -> Pattern -> Ordering

(<) :: Pattern -> Pattern -> Bool

(<=) :: Pattern -> Pattern -> Bool

(>) :: Pattern -> Pattern -> Bool

(>=) :: Pattern -> Pattern -> Bool

max :: Pattern -> Pattern -> Pattern

min :: Pattern -> Pattern -> Pattern

Show Pattern

Methods

showsPrec :: Int -> Pattern -> ShowS

show :: Pattern -> String

showList :: [Pattern] -> ShowS

data Refs

Refs is a map from reference name to pattern and describes a relapse grammar.

Instances

Eq Refs

Methods

(==) :: Refs -> Refs -> Bool

(/=) :: Refs -> Refs -> Bool

Show Refs

Methods

showsPrec :: Int -> Refs -> ShowS

show :: Refs -> String

showList :: [Refs] -> ShowS

emptyRef :: Refs

emptyRef returns an empty reference map.

union :: Refs -> Refs -> Refs

union returns the union of two reference maps.

newRef :: String -> Pattern -> Refs

newRef returns a new reference map given a single pattern and its reference name.

reverseLookupRef :: Pattern -> Refs -> Maybe String

reverseLookupRef returns the reference name for a given pattern.

lookupRef :: Refs -> String -> Pattern

lookupRef looks up a pattern in the reference map, given a reference name.

hasRecursion :: Refs -> Bool

hasRecursion returns whether an relapse grammar has any recursion, starting from the "main" reference.

nullable :: Refs -> Pattern -> Bool

The nullable function returns whether a pattern is nullable. This means that the pattern matches the empty string.

unescapable :: Pattern -> Bool

unescapable is used for short circuiting. A part of the tree can be skipped if all patterns are unescapable.