Text.Regex.XMLSchema.String

hxt-regex-xmlschema-9.2.0.7: A regular expression library for W3C XML Schema regular expressions

Copyright | Copyright (C) 2010- Uwe Schmidt
License | MIT
Maintainer | Uwe Schmidt <uwe@fh-wedel.de>
Stability | stable
Portability | portable
Safe Haskell | Safe-Inferred
Language | Haskell2010

Text.Regex.XMLSchema.String

Description

Deprecated: use the more general `Generic` instead

Convenient functions for W3C XML Schema Regular Expression Matcher for Strings. A specialisation of Text.Regex.XMLSchema.Generic as compatibility module to old non generic version

Grammar can be found under http://www.w3.org/TR/xmlschema11-2/#regexs

Synopsis

- type Regex = GenRegex String
- grep :: String -> [String] -> [String]
- grepExt :: String -> [String] -> [String]
- grepRE :: Regex -> [String] -> [String]
- grepREwithLineNum :: Regex -> [String] -> [(Int, String)]
- match :: String -> String -> Bool
- matchExt :: String -> String -> Bool
- matchSubex :: String -> String -> [(String, String)]
- sed :: (String -> String) -> String -> String -> String
- sedExt :: (String -> String) -> String -> String -> String
- split :: String -> String -> (String, String)
- splitExt :: String -> String -> (String, String)
- splitSubex :: String -> String -> ([(String, String)], String)
- tokenize :: String -> String -> [String]
- tokenizeExt :: String -> String -> [String]
- tokenize' :: String -> String -> [Either String String]
- tokenizeExt' :: String -> String -> [Either String String]
- tokenizeSubex :: String -> String -> [(String, String)]
- matchRE :: Regex -> String -> Bool
- matchSubexRE :: Regex -> String -> [(String, String)]
- sedRE :: (String -> String) -> Regex -> String -> String
- splitRE :: Regex -> String -> Maybe (String, String)
- splitSubexRE :: Regex -> String -> Maybe ([(String, String)], String)
- tokenizeRE :: Regex -> String -> [String]
- tokenizeRE' :: Regex -> String -> [Either String String]
- tokenizeSubexRE :: Regex -> String -> [(String, String)]
- mkZero :: s -> GenRegex s
- mkUnit :: GenRegex s
- mkSym1 :: StringLike s => Char -> GenRegex s
- mkSymRng :: StringLike s => Char -> Char -> GenRegex s
- mkWord :: StringLike s => [Char] -> GenRegex s
- mkDot :: GenRegex s
- mkStar :: StringLike s => GenRegex s -> GenRegex s
- mkAll :: StringLike s => GenRegex s
- mkAlt :: StringLike s => GenRegex s -> GenRegex s -> GenRegex s
- mkElse :: StringLike s => GenRegex s -> GenRegex s -> GenRegex s
- mkSeq :: GenRegex s -> GenRegex s -> GenRegex s
- mkSeqs :: [GenRegex s] -> GenRegex s
- mkRep :: StringLike s => Int -> GenRegex s -> GenRegex s
- mkRng :: StringLike s => Int -> Int -> GenRegex s -> GenRegex s
- mkOpt :: StringLike s => GenRegex s -> GenRegex s
- mkDiff :: StringLike s => GenRegex s -> GenRegex s -> GenRegex s
- mkIsect :: StringLike s => GenRegex s -> GenRegex s -> GenRegex s
- mkExor :: StringLike s => GenRegex s -> GenRegex s -> GenRegex s
- mkCompl :: StringLike s => GenRegex s -> GenRegex s
- mkBr :: s -> GenRegex s -> GenRegex s
- isZero :: GenRegex s -> Bool
- errRegex :: StringLike s => GenRegex s -> s
- parseRegex :: StringLike s => s -> GenRegex s
- parseRegexExt :: StringLike s => s -> GenRegex s
- parseContextRegex :: StringLike s => (String -> GenRegex s) -> s -> GenRegex s

# Documentation

type Regex = GenRegex String #

grep :: String -> [String] -> [String] #

grep like filter for lists of strings

The regular expression may be prefixed with the usual context spec "^" for start of string, and "\<" for start of word. and suffixed with "$" for end of text and "\>" end of word. Word chars are defined by the multi char escape sequence "\w"

Examples

    grep "a"    ["_a_", "_a", "a_", "a", "_"]      => ["_a_", "_a", "a_", "a"]
    grep "^a"   ["_a_", "_a", "a_", "a", "_"]      => ["a_", "a"]
    grep "a$"   ["_a_", "_a", "a_", "a", "_"]      => ["_a", "a"]
    grep "^a$"  ["_a_", "_a", "a_", "a", "_"]      => ["a"]
    grep "\\<a" ["x a b", " ax ", " xa ", "xab"]   => ["x a b", " ax "]
    grep "a\\>" ["x a b", " ax ", " xa ", "xab"]   => ["x a b", " xa "]

grepExt :: String -> [String] -> [String] #

grep with extended regular expressions

grepRE :: Regex -> [String] -> [String] #

grep with already prepared Regex (ususally with `parseContextRegex`)

grepREwithLineNum :: Regex -> [String] -> [(Int, String)] #

grep with Regex and line numbers

match :: String -> String -> Bool #

convenient function for `matchRE`

Examples:

    match "x*" "xxx" = True
    match "x" "xxx"  = False
    match "[" "xxx"  = False

matchExt :: String -> String -> Bool #

match with extended regular expressions

matchSubex :: String -> String -> [(String, String)] #

convenient function for `matchRE`

Examples:

    matchSubex "({1}x*)"                 "xxx"      = [("1","xxx")]
    matchSubex "({1}x*)"                 "y"        = []
    matchSubex "({w}[0-9]+)x({h}[0-9]+)" "800x600"  = [("w","800"),("h","600")]
    matchSubex "[" "xxx"                            = []

sed :: (String -> String) -> String -> String -> String #

convenient function for `sedRE`

examples:

    sed (const "b") "a" "xaxax"       = "xbxbx"
    sed (\ x -> x ++ x) "a" "xax"     = "xaax"
    sed undefined       "[" "xxx"     = "xxx"

sedExt :: (String -> String) -> String -> String -> String #

split :: String -> String -> (String, String) #

convenient function for `splitRE`

examples:

    split "a*b" "abc" = ("ab","c")
    split "a*"  "bc"  = ("", "bc")    -- "a*" matches ""
    split "a+"  "bc"  = ("", "bc")    -- "a+" does not match, no split
    split "["   "abc" = ("", "abc")   -- "["  syntax error, no split

splitExt :: String -> String -> (String, String) #

split with extended syntax

splitSubex :: String -> String -> ([(String, String)], String) #

convenient function for `splitSubex`, uses extended syntax

examples:

    splitSubex "({1}a*)b"  "abc" = ([("1","a")],"c")
    splitSubex "({2}a*)"   "bc"  = ([("2","")], "bc")
    splitSubex "({1}a|b)+" "abc" = ([("1","a"),("1","b")],"c")        -- subex 1 matches 2 times

    splitSubex ".*({x}a*)" "aa"  = ([("x",""),("x","a"),("x","aa")],"")
                                                                      -- nondeterminism: 3 matches for a*

    splitSubex "({1}do)|({2}[a-z]+)" "do you know"
                                   = ([("1","do"),("2","do")]," you know")
                                                                      -- nondeterminism: 2 matches for do

    splitSubex "({1}do){|}({2}[a-z]+)" "do you know"
                                   = ([("1","do")]," you know")
                                                                      -- no nondeterminism with {|}: 1. match for do

    splitSubex "({1}a+)"   "bcd" = ([], "bcd")                        -- no match
    splitSubex "["         "abc" = ([], "abc")                        -- syntax error

tokenize :: String -> String -> [String] #

split a string into tokens (words) by giving a regular expression which all tokens must match.

Convenient function for `tokenizeRE`

This can be used for simple tokenizers. It is recommended to use regular expressions where the empty word does not match. Else there will appear a lot of probably useless empty tokens in the output. All none matching chars are discarded. If the given regex contains syntax errors, `Nothing` is returned

examples:

    tokenize "a" "aabba"      = ["a","a","a"]
    tokenize "a*" "aaaba"     = ["aaa","a"]
    tokenize "a*" "bbb"       = ["","",""]
    tokenize "a+" "bbb"       = []

    tokenize "a*b" ""         = []
    tokenize "a*b" "abc"      = ["ab"]
    tokenize "a*b" "abaab ab" = ["ab","aab","ab"]

    tokenize "[a-z]{2,}|[0-9]{2,}|[0-9]+[.][0-9]+" "ab123 456.7abc"
                              = ["ab","123","456.7","abc"]

    tokenize "[a-z]*|[0-9]{2,}|[0-9]+[.][0-9]+" "cab123 456.7abc"
                              = ["cab","123","456.7","abc"]

    tokenize "[^ \t\n\r]*" "abc def\t\n\rxyz"
                              = ["abc","def","xyz"]

    tokenize ".*"   "\nabc\n123\n\nxyz\n"
                              = ["","abc","123","","xyz"]

    tokenize ".*"             = lines

    tokenize "[^ \t\n\r]*"    = words

tokenizeExt :: String -> String -> [String] #

tokenize with extended syntax

tokenize' :: String -> String -> [Either String String] #

convenient function for `tokenizeRE'`

When the regular expression parses as Zero, `[Left input]` is returned, that means no tokens are found

tokenizeExt' :: String -> String -> [Either String String] #

tokenizeSubex :: String -> String -> [(String, String)] #

convenient function for `tokenizeSubexRE` a string

examples:

    tokenizeSubex "({name}[a-z]+)|({num}[0-9]{2,})|({real}[0-9]+[.][0-9]+)"
                    "cab123 456.7abc"
                                     = [("name","cab")
                                       ,("num","123")
                                       ,("real","456.7")
                                       ,("name","abc")]

    tokenizeSubex "({real}({n}[0-9]+)([.]({f}[0-9]+))?)"
                    "12.34"          = [("real","12.34")
                                       ,("n","12")
                                       ,("f","34")]

    tokenizeSubex "({real}({n}[0-9]+)([.]({f}[0-9]+))?)"
                     "12 34"         = [("real","12"),("n","12")
                                       ,("real","34"),("n","34")]

    tokenizeSubex "({real}({n}[0-9]+)(([.]({f}[0-9]+))|({f})))"
                     "12 34.56"      = [("real","12"),("n","12"),("f","")
                                       ,("real","34.56"),("n","34"),("f","56")]

matchRE :: Regex -> String -> Bool #

match a string with a regular expression

matchSubexRE :: Regex -> String -> [(String, String)] #

match a string with a regular expression and extract subexpression matches

sedRE :: (String -> String) -> Regex -> String -> String #

sed like editing function

All matching tokens are edited by the 1. argument, the editing function, all other chars remain as they are

splitRE :: Regex -> String -> Maybe (String, String) #

split a string by taking the longest prefix matching a regular expression

`Nothing` is returned in case there is no matching prefix, else the pair of prefix and rest is returned

splitSubexRE :: Regex -> String -> Maybe ([(String, String)], String) #

split a string by removing the longest prefix matching a regular expression and then return the list of subexpressions found in the matching part

`Nothing` is returned in case of no matching prefix, else the list of pairs of labels and submatches and the rest is returned

tokenizeRE :: Regex -> String -> [String] #

The function, that does the real work for `tokenize`

tokenizeRE' :: Regex -> String -> [Either String String] #

split a string into tokens and delimierter by giving a regular expression wich all tokens must match

This is a generalisation of the above `tokenizeRE` functions. The none matching char sequences are marked with `Left`, the matching ones are marked with `Right`

If the regular expression contains syntax errors `Nothing` is returned

The following Law holds:

    concat . map (either id id) . tokenizeRE' re == id

tokenizeSubexRE :: Regex -> String -> [(String, String)] #

split a string into tokens (pair of labels and words) by giving a regular expression containing labeled subexpressions.

This function should not be called with regular expressions without any labeled subexpressions. This does not make sense, because the result list will always be empty.

Result is the list of matching subexpressions This can be used for simple tokenizers. At least one char is consumed by parsing a token. The pairs in the result list contain the matching substrings. All none matching chars are discarded. If the given regex contains syntax errors, `Nothing` is returned

mkZero :: s -> GenRegex s #

construct the r.e. for the empty set. An (error-) message may be attached

mkUnit :: GenRegex s #

construct the r.e. for the set containing the empty word

mkSym1 :: StringLike s => Char -> GenRegex s #

construct an r.e. for a single char set

mkSymRng :: StringLike s => Char -> Char -> GenRegex s #

construct an r.e. for an intervall of chars

mkWord :: StringLike s => [Char] -> GenRegex s #

mkSym generaized for strings

mkDot :: GenRegex s #

construct an r.e. for the set of all Unicode chars

mkStar :: StringLike s => GenRegex s -> GenRegex s #

construct r.e. for r*

mkAll :: StringLike s => GenRegex s #

construct an r.e. for the set of all Unicode words

mkAlt :: StringLike s => GenRegex s -> GenRegex s -> GenRegex s #

construct the r.e for r1|r2

mkElse :: StringLike s => GenRegex s -> GenRegex s -> GenRegex s #

construct the r.e. for r1{|}r2 (r1 orElse r2).

This represents the same r.e. as r1|r2, but when collecting the results of subexpressions in (...) and r1 succeeds, the subexpressions of r2 are discarded, so r1 matches are prioritized

example

    splitSubex "({1}x)|({2}.)"   "x" = ([("1","x"),("2","x")], "")

    splitSubex "({1}x){|}({2}.)" "x" = ([("1","x")], "")

mkSeq :: GenRegex s -> GenRegex s -> GenRegex s #

Construct the sequence r.e. r1.r2

mkSeqs :: [GenRegex s] -> GenRegex s #

mkSeq extened to lists

mkRep :: StringLike s => Int -> GenRegex s -> GenRegex s #

Construct repetition r{i,}

mkRng :: StringLike s => Int -> Int -> GenRegex s -> GenRegex s #

Construct range r{i,j}

mkOpt :: StringLike s => GenRegex s -> GenRegex s #

Construct option r?

mkDiff :: StringLike s => GenRegex s -> GenRegex s -> GenRegex s #

Construct difference r.e.: r1 {\} r2

example

    match "[a-z]+{\\}bush" "obama"     = True
    match "[a-z]+{\\}bush" "clinton"   = True
    match "[a-z]+{\\}bush" "bush"      = False     -- not important any more

mkIsect :: StringLike s => GenRegex s -> GenRegex s -> GenRegex s #

Construct r.e. for intersection: r1 {&} r2

example

    match ".*a.*{&}.*b.*" "-a-b-"  = True
    match ".*a.*{&}.*b.*" "-b-a-"  = True
    match ".*a.*{&}.*b.*" "-a-a-"  = False
    match ".*a.*{&}.*b.*" "---b-"  = False

mkExor :: StringLike s => GenRegex s -> GenRegex s -> GenRegex s #

Construct r.e. for exclusive or: r1 {^} r2

example

    match "[a-c]+{^}[c-d]+" "abc"  = True
    match "[a-c]+{^}[c-d]+" "acdc" = False
    match "[a-c]+{^}[c-d]+" "ccc"  = False
    match "[a-c]+{^}[c-d]+" "cdc"  = True

mkCompl :: StringLike s => GenRegex s -> GenRegex s #

Construct the Complement of an r.e.: whole set of words - r

mkBr :: s -> GenRegex s -> GenRegex s #

Construct a labeled subexpression: ({label}r)

isZero :: GenRegex s -> Bool #

errRegex :: StringLike s => GenRegex s -> s #

parseRegex :: StringLike s => s -> GenRegex s #

parse a standard W3C XML Schema regular expression

parseRegexExt :: StringLike s => s -> GenRegex s #

parse an extended syntax W3C XML Schema regular expression

The Syntax of the W3C XML Schema spec is extended by further useful set operations, like intersection, difference, exor. Subexpression match becomes possible with "named" pairs of parentheses. The multi char escape sequence \a represents any Unicode char, The multi char escape sequence \A represents any Unicode word, (\A = \a*). All syntactically wrong inputs are mapped to the Zero expression representing the empty set of words. Zero contains as data field a string for an error message. So error checking after parsing becomes possible by checking against Zero (`isZero` predicate)

parseContextRegex :: StringLike s => (String -> GenRegex s) -> s -> GenRegex s #

parse a regular expression surrounded by contenxt spec

a leading `^` denotes start of text, a trailing `$` denotes end of text, a leading `\<` denotes word start, a trailing `\>` denotes word end.

The 1. param ist the regex parser (`parseRegex` or `parseRegexExt`)