regex-tdfa-1.1.1: Replaces/Enhances Text.Regex Contents Index

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

data Pattern = PEmpty | PGroup (Maybe GroupIndex) Pattern | POr [Pattern] | PConcat [Pattern] | PQuest Pattern | PPlus Pattern | PStar Bool Pattern | PBound Int (Maybe Int) Pattern | PCarat { getDoPa :: DoPa } | PDollar { getDoPa :: DoPa } | PDot { getDoPa :: DoPa } | PAny { getDoPa :: DoPa getPatternSet :: PatternSet } | PAnyNot { getDoPa :: DoPa getPatternSet :: PatternSet } | PEscape { getDoPa :: DoPa getPatternChar :: Char } | PChar { getDoPa :: DoPa getPatternChar :: Char } | PNonCapture Pattern | PNonEmpty Pattern data PatternSet = PatternSet (Maybe (Set Char)) (Maybe (Set PatternSetCharacterClass)) (Maybe (Set PatternSetCollatingElement)) (Maybe (Set PatternSetEquivalenceClass)) newtype PatternSetCharacterClass = PatternSetCharacterClass { unSCC :: String } newtype PatternSetCollatingElement = PatternSetCollatingElement { unSCE :: String } newtype PatternSetEquivalenceClass = PatternSetEquivalenceClass { unSEC :: String } type GroupIndex = Int newtype DoPa = DoPa { dopaIndex :: Int } showPattern :: Pattern -> String starTrans :: Pattern -> Pattern starTrans' :: Pattern -> Pattern simplify' :: Pattern -> Pattern dfsPattern :: (Pattern -> Pattern) -> Pattern -> Pattern

Documentation

data Pattern

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 getDoPa :: DoPa PDollar getDoPa :: DoPa PDot getDoPa :: DoPa PAny getDoPa :: DoPa getPatternSet :: PatternSet PAnyNot getDoPa :: DoPa getPatternSet :: PatternSet PEscape getDoPa :: DoPa getPatternChar :: Char PChar getDoPa :: DoPa getPatternChar :: Char PNonCapture Pattern PNonEmpty Pattern Instances Eq Pattern Show Pattern

data PatternSet

Constructors PatternSet (Maybe (Set Char)) (Maybe (Set PatternSetCharacterClass)) (Maybe (Set PatternSetCollatingElement)) (Maybe (Set PatternSetEquivalenceClass)) Instances Eq PatternSet Show PatternSet

newtype PatternSetCharacterClass

Constructors PatternSetCharacterClass unSCC :: String Instances Eq PatternSetCharacterClass Ord PatternSetCharacterClass Show PatternSetCharacterClass

newtype PatternSetCollatingElement

Constructors PatternSetCollatingElement unSCE :: String Instances Eq PatternSetCollatingElement Ord PatternSetCollatingElement Show PatternSetCollatingElement

newtype PatternSetEquivalenceClass

Constructors PatternSetEquivalenceClass unSEC :: String Instances Eq PatternSetEquivalenceClass Ord PatternSetEquivalenceClass Show PatternSetEquivalenceClass

type GroupIndex = Int

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

newtype DoPa

Used to track elements of the pattern that accept characters or are anchors Constructors DoPa dopaIndex :: Int Instances Enum DoPa Eq DoPa Ord DoPa Show DoPa

showPattern :: Pattern -> String

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

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

simplify' :: Pattern -> Pattern

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

dfsPattern

:: Pattern -> Pattern The transformation function -> Pattern The Pattern to transform -> Pattern The transformed Pattern Apply a Pattern transfomation function depth first

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