Text.Regex.TDFA.Pattern

Contents

Internal use
Internal use, Operations to support debugging under ghci

Description

This Text.Regex.TDFA.Pattern module provides the Pattern data type and its subtypes. This Pattern type is used to represent the parsed form of a Regular Expression.

Synopsis

Documentation

data Pattern Source

Pattern is the type returned by the regular expression parser. This is consumed by the CorePattern module and the tender leaves are nibbled by the TNFA module.

Constructors

PEmpty
PGroup (Maybe GroupIndex) Pattern
POr [Pattern]
PConcat [Pattern]
PQuest Pattern
PPlus Pattern
PStar Bool Pattern
PBound Int (Maybe Int) Pattern
PCarat
Fields getDoPa :: DoPa
PDollar
Fields getDoPa :: DoPa
PDot
Fields getDoPa :: DoPa
PAny
Fields getDoPa :: DoPa getPatternSet :: PatternSet
PAnyNot
Fields getDoPa :: DoPa getPatternSet :: PatternSet
PEscape
Fields getDoPa :: DoPa getPatternChar :: Char
PChar
Fields getDoPa :: DoPa getPatternChar :: Char
PNonCapture Pattern
PNonEmpty Pattern

Instances

Eq Pattern
Show Pattern

data PatternSet Source

Constructors

PatternSet (Maybe (Set Char)) (Maybe (Set PatternSetCharacterClass)) (Maybe (Set PatternSetCollatingElement)) (Maybe (Set PatternSetEquivalenceClass))

Instances

Eq PatternSet
Show PatternSet

newtype PatternSetCharacterClass Source

Constructors

PatternSetCharacterClass
Fields unSCC :: String

Instances

Eq PatternSetCharacterClass
Ord PatternSetCharacterClass
Show PatternSetCharacterClass

newtype PatternSetCollatingElement Source

Constructors

PatternSetCollatingElement
Fields unSCE :: String

Instances

Eq PatternSetCollatingElement
Ord PatternSetCollatingElement
Show PatternSetCollatingElement

newtype PatternSetEquivalenceClass Source

Constructors

PatternSetEquivalenceClass
Fields unSEC :: String

Instances

Eq PatternSetEquivalenceClass
Ord PatternSetEquivalenceClass
Show PatternSetEquivalenceClass

type GroupIndex = Int Source

GroupIndex is for indexing submatches from capturing parenthesized groups (PGroup/Group)

newtype DoPa Source

Used to track elements of the pattern that accept characters or are anchors

Constructors

DoPa
Fields dopaIndex :: Int

Instances

Enum DoPa
Eq DoPa
Ord DoPa
Show DoPa

showPattern :: Pattern -> String Source

I have not been checking, but this should have the property that parsing the resulting string should result in an identical Pattern. This is not true if starTrans has created PNonCapture and PNonEmpty values or a (PStar False). The contents of a [ ] grouping are always shown in a sorted canonical order.

Internal use

starTrans :: Pattern -> Pattern Source

Do the transformation and simplification in a single traversal. This removes the PPlus, PQuest, and PBound values, changing to POr and PEmpty and PStar True/False. For some PBound values it adds PNonEmpty and PNonCapture semantic marker. It also simplifies to flatten out nested POr and PConcat instances and eliminate some uneeded PEmpty values.

Internal use, Operations to support debugging under ghci

starTrans' :: Pattern -> Pattern Source

simplify' :: Pattern -> Pattern Source

Function to transform a pattern into an equivalent, but less redundant form. Nested POr and PConcat are flattened. PEmpty is propagated.

dfsPattern Source

Arguments

:: (Pattern -> Pattern)	The transformation function
-> Pattern	The Pattern to transform
-> Pattern	The transformed Pattern

Apply a Pattern transfomation function depth first