| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
BNFC.Types.Regex
Description
Tools to manipulate regular expressions.
Synopsis
- data Regex
- pattern REmpty :: Regex
- pattern RAlt :: Regex -> Regex -> Regex
- pattern RSeq :: Regex -> Regex -> Regex
- nullable :: Regex -> Bool
- class Satisfiable a where
- satisfiable :: a -> Bool
- data CharClass = CMinus {}
- pattern CEmpty :: CharClass
- pattern CC :: CharClassUnion -> CharClass
- data CharClassUnion
- = CAny
- | CAlt [CharClassAtom]
- pattern CCEmpty :: CharClassUnion
- data CharClassAtom
- rChar :: Char -> Regex
- rSeq :: Regex -> Regex -> Regex
- rSeqs :: [Regex] -> Regex
- rAlt :: Regex -> Regex -> Regex
- rAlts :: [Regex] -> Regex
- rMinus :: Regex -> Regex -> Regex
- rStar :: Regex -> Regex
- rPlus :: Regex -> Regex
- rOpt :: Regex -> Regex
- cAlt :: CharClass -> CharClass -> Regex
- cMinus :: CharClass -> CharClass -> Regex
- cChar :: Char -> CharClass
- cAlts :: [Char] -> CharClass
- cDigit :: CharClass
- cLower :: CharClass
- cUpper :: CharClass
- cLetter :: CharClass
- cAny :: CharClass
- cAtom :: CharClassAtom -> CharClass
- ccuMinus :: CharClassUnion -> CharClassUnion -> Either CharClass CharClassUnion
- onlyOneChar :: CharClassUnion -> Bool
- isEmpty :: CharClassUnion -> Bool
Regular expressions
Regular expressions are constructed over character classes.
Use smart constructors to ensure invariants.
Constructors
| RChar CharClass | Atomic regular expression. |
| RAlts (List2 Regex) | Alternative/sum: List free of duplicates and |
| RMinus Regex Regex | Difference. Most lexer generators do not support difference in general, only at the level of character classes. LBNF has general difference, so it is represented here. |
| REps | Language of the empty word (empty sequence). |
| RSeqs (List2 Regex) | Sequence/product. List free of |
| RStar Regex | 0 or more repetitions.
|
| RPlus Regex | 1 or more repetitions.
|
| ROpt Regex | 0 or 1 repetitions.
|
Instances
| Eq Regex Source # | |
| Ord Regex Source # | |
Defined in BNFC.Types.Regex | |
| Show Regex Source # | |
| Satisfiable Regex Source # | |
Defined in BNFC.Types.Regex Methods satisfiable :: Regex -> Bool Source # | |
| ReifyRegex Regex Source # | |
Defined in BNFC.Check.Regex Methods reifyRegex :: Regex -> Reg Source # | |
| Print Regex Source # | |
| Print Regex Source # | |
| Print Regex Source # | |
nullable :: Regex -> Bool Source #
Check if a regular expression is nullable (accepts the empty string).
class Satisfiable a where Source #
Check if a regular expression matches at least one word.
For differences, this check may err on the positive side.
Methods
satisfiable :: a -> Bool Source #
Instances
| Satisfiable CharClassUnion Source # | |
Defined in BNFC.Types.Regex Methods satisfiable :: CharClassUnion -> Bool Source # | |
| Satisfiable CharClass Source # | |
Defined in BNFC.Types.Regex Methods satisfiable :: CharClass -> Bool Source # | |
| Satisfiable Regex Source # | |
Defined in BNFC.Types.Regex Methods satisfiable :: Regex -> Bool Source # | |
Character classes
Character classes are regular expressions that recognize
character sequences of length exactly one. These are often
distinguished from arbitrary regular expressions in lexer
generators, e.g. in alex.
We represent character classes as a difference of unions of atomic character classes.
Semantics: ⟦ CMinus ccYes ccNo ⟧ = ⟦ ccYes ⟧ ⟦ ccNo ⟧
Constructors
| CMinus | |
Fields
| |
Instances
| Eq CharClass Source # | |
| Ord CharClass Source # | |
Defined in BNFC.Types.Regex | |
| Show CharClass Source # | |
| Satisfiable CharClass Source # | |
Defined in BNFC.Types.Regex Methods satisfiable :: CharClass -> Bool Source # | |
| ReifyRegex CharClass Source # | |
Defined in BNFC.Check.Regex Methods reifyRegex :: CharClass -> Reg Source # | |
pattern CC :: CharClassUnion -> CharClass Source #
data CharClassUnion Source #
Possibly overlapping union of character classes.
Constructors
| CAny | Any character, LBNF |
| CAlt [CharClassAtom] | Any of the given (≥0) alternatives. List is free of duplicates. |
Instances
pattern CCEmpty :: CharClassUnion Source #
data CharClassAtom Source #
Atomic character class.
Constructors
| CChar Char | A single character. |
| CDigit |
|
| CLower | Lower case character, LBNF |
| CUpper | Upper case character, LBNF |
Instances
| Eq CharClassAtom Source # | |
Defined in BNFC.Types.Regex Methods (==) :: CharClassAtom -> CharClassAtom -> Bool Source # (/=) :: CharClassAtom -> CharClassAtom -> Bool Source # | |
| Ord CharClassAtom Source # | |
Defined in BNFC.Types.Regex Methods compare :: CharClassAtom -> CharClassAtom -> Ordering Source # (<) :: CharClassAtom -> CharClassAtom -> Bool Source # (<=) :: CharClassAtom -> CharClassAtom -> Bool Source # (>) :: CharClassAtom -> CharClassAtom -> Bool Source # (>=) :: CharClassAtom -> CharClassAtom -> Bool Source # max :: CharClassAtom -> CharClassAtom -> CharClassAtom Source # min :: CharClassAtom -> CharClassAtom -> CharClassAtom Source # | |
| Show CharClassAtom Source # | |
Defined in BNFC.Types.Regex | |
| Print CharClassAtom Source # | |
Defined in BNFC.Backend.Txt2Tags.Txt2Tags | |
| Print CharClassAtom Source # | |
Defined in BNFC.Backend.Latex.Latex | |
| Print CharClassAtom Source # | |
Defined in BNFC.Backend.Haskell.Lexer | |
Smart constructor for regular expressions.
Smart constructors for character classes.
cAtom :: CharClassAtom -> CharClass Source #
ccuMinus :: CharClassUnion -> CharClassUnion -> Either CharClass CharClassUnion Source #
Smart constructor for CharClass from difference..
Mutually reduce: (A - B) = (A B) - (B A)
onlyOneChar :: CharClassUnion -> Bool Source #
isEmpty :: CharClassUnion -> Bool Source #