regex -package:regex-compat

Match requests using a regular expression. Named captures are not yet supported.

>>> :{
let server = S.get (S.regex "^/f(.*)r$") $ do
cap <- S.pathParam "1"
S.text cap
in do
withScotty server $ curl "http://localhost:3000/foo/bar"
:}
"oo/ba"

Compile a regular expression with the given options. This function throws a ParseError if the pattern is invalid, so it is best for use when the pattern is statically known.

Compile a regular expression with the given options. This function throws a ParseError if the pattern is invalid. The Regex is initialized with empty text to search against.

Toolkit for regex-base A regular expression toolkit for regex-base with compile-time checking of RE syntax, data types for matches and captures, a text replacement toolkit, portable options, high-level AWK-like tools for building text processing apps, regular expression macros with parsers and test bench, comprehensive documentation, tutorials and copious examples.

Builds a traversal over text using a Regex pattern It's a QuasiQuoter which creates a Traversal out of the given regex string. It's equivalent to calling regexing on a Regex created using the re QuasiQuoter. The "real" type is:

regex :: Regex -> IndexedTraversal' Int BS.ByteString Match

It's a traversal which selects Matches; compose it with match or groups to get the relevant parts of your match.

>>> txt = "raindrops on roses and whiskers on kittens"

Search

>>> has ([regex|whisk|]) txt
True

Get matches

>>> txt ^.. [regex|\br\w+|] . match
["raindrops","roses"]

Edit matches

>>> txt & [regex|\br\w+|] . match %~ Char8.intersperse '-' . Char8.map toUpper
"R-A-I-N-D-R-O-P-S on R-O-S-E-S and whiskers on kittens"

Get Groups

>>> txt ^.. [regex|(\w+) on (\w+)|] . groups
[["raindrops","roses"],["whiskers","kittens"]]

Edit Groups

>>> txt & [regex|(\w+) on (\w+)|] . groups %~ reverse
"roses on raindrops and kittens on whiskers"

Get the third match

>>> txt ^? [regex|\w+|] . index 2 . match
Just "roses"

Edit matches

>>> txt & [regex|\br\w+|] . match %~ Char8.intersperse '-' . Char8.map toUpper
"R-A-I-N-D-R-O-P-S on R-O-S-E-S and whiskers on kittens"

Get Groups

>>> txt ^.. [regex|(\w+) on (\w+)|] . groups
[["raindrops","roses"],["whiskers","kittens"]]

Edit Groups

>>> txt & [regex|(\w+) on (\w+)|] . groups %~ reverse
"roses on raindrops and kittens on whiskers"

Get the third match

>>> txt ^? [regex|\w+|] . index 2 . match
Just "roses"

Match integers, Read them into ints, then sort them in-place dumping them back into the source text afterwards.

>>> "Monday: 29, Tuesday: 99, Wednesday: 3" & partsOf ([regex|\d+|] . match . from packedChars . _Show @Int) %~ sort
"Monday: 3, Tuesday: 29, Wednesday: 99"

To alter behaviour of the regex you may wish to pass PCREOptions when compiling it. The default behaviour may seem strange in certain cases; e.g. it operates in 'single-line' mode. You can compile the Regex separately and add any options you like, then pass the resulting Regex into regex; Alternatively can make your own version of the QuasiQuoter with any options you want embedded by using mkRegexQQ.

Builds a traversal over text using a Regex pattern It's a QuasiQuoter which creates a Traversal out of the given regex string. It's equivalent to calling regexing on a Regex created using the re QuasiQuoter. The "real" type is:

regex :: Regex -> IndexedTraversal' Int T.Text Match

It's a traversal which selects Matches; compose it with match or groups to get the relevant parts of your match.

>>> txt = "raindrops on roses and whiskers on kittens"

Search

>>> has ([regex|whisk|]) txt
True

Get matches

>>> txt ^.. [regex|\br\w+|] . match
["raindrops","roses"]

Edit matches

>>> txt & [regex|\br\w+|] . match %~ T.intersperse '-' . T.toUpper
"R-A-I-N-D-R-O-P-S on R-O-S-E-S and whiskers on kittens"

Get Groups

>>> txt ^.. [regex|(\w+) on (\w+)|] . groups
[["raindrops","roses"],["whiskers","kittens"]]

Edit Groups

>>> txt & [regex|(\w+) on (\w+)|] . groups %~ reverse
"roses on raindrops and kittens on whiskers"

Get the third match

>>> txt ^? [regex|\w+|] . index 2 . match
Just "roses"

Edit matches

>>> txt & [regex|\br\w+|] . match %~ T.intersperse '-' . T.toUpper
"R-A-I-N-D-R-O-P-S on R-O-S-E-S and whiskers on kittens"

Get Groups

>>> txt ^.. [regex|(\w+) on (\w+)|] . groups
[["raindrops","roses"],["whiskers","kittens"]]

Edit Groups

>>> txt & [regex|(\w+) on (\w+)|] . groups %~ reverse
"roses on raindrops and kittens on whiskers"

Get the third match

>>> txt ^? [regex|\w+|] . index 2 . match
Just "roses"

Match integers, Read them into ints, then sort them in-place dumping them back into the source text afterwards.

>>> "Monday: 29, Tuesday: 99, Wednesday: 3" & partsOf ([regex|\d+|] . match . unpacked . _Show @Int) %~ sort
"Monday: 3, Tuesday: 29, Wednesday: 99"

To alter behaviour of the regex you may wish to pass PCREOptions when compiling it. The default behaviour may seem strange in certain cases; e.g. it operates in 'single-line' mode. You can compile the Regex separately and add any options you like, then pass the resulting Regex into regex; Alternatively can make your own version of the QuasiQuoter with any options you want embedded by using mkRegexQQ. regex :: Regex -> IndexedTraversal' Int T.Text RBS.Match

An indexed Traversal for matched part with regexp.

>>> "foo bar baz" ^? regex [r|b.*r|]
Just (MatchPart {_matchedString = "bar", _captures = []})

>>> "foo bar baz" ^? regex [r|hoge|]
Nothing

You can access to the matched string by using matchedString:

>>> "foo bar baz" ^? regex [r|b.*r|] . matchedString
Just "bar"

Multiple result:

>>> "foo bar baz" ^.. regex [r|b[^ ]+|] . matchedString
["bar","baz"]

Replace:

>>> "foo bar baz" & regex [r|b[^ ]+|] . matchedString .~ "nya"
"foo nya nya"

Indexing:

>>> "foo bar baz" ^.. regex [r|b[^ ]+|] . index 1 . matchedString
["baz"]

>>> "foo bar baz" & regex [r|b[^ ]+|] . index 1 . matchedString .~ "nya"
"foo bar nya"

Captures:

>>> "foo00 bar01 baz02" ^.. regex [r|([a-z]+)([0-9]+)|] . captures
[["foo","00"],["bar","01"],["baz","02"]]

>>> "foo00 bar01 baz02" ^.. regex [r|([a-z]+)([0-9]+)|] . captures . traversed . index 1
["00","01","02"]

Note: This is not a legal Traversal, unless you are very careful not to invalidate the predicate on the target. For example, if you replace the matched part with a string which is not match with the regex, the second Traversal law is violated.

let l = regex [r|t.*t|] . matchedString
over l (++ "peta") . over l (++ "nya") /= over l ((++ "peta") . (++ "nya"))
over l (++ "put") . over l (++ "hot") == over l ((++ "put") . (++ "hot"))

As an expression

regex :: (Alternative f) => String -> Text -> f (Captures info)

if there are parenthesized captures, or

regex :: (Alternative f) => String -> Text -> f Text

if there are none. In other words, if there is more than the 0th capture, this behaves like captures (except returning an opaque Captures instead of a NonEmpty list), otherwise it behaves like match. To retrieve an individual capture from a Captures, use capture.

case [regex|(?<y>\d{4})-(?<m>\d{2})-(?<d>\d{2})|] "submitted 2020-10-20" of
Just cs ->
let date = capture @0 cs
year = read @Int $ Text.unpack $ capture @"y" cs
...

forM_ @Maybe ([regex|\s+$|] line) $ \spaces ->
printf "line has trailing spaces (%d characters)\n" (Text.length spaces)

As a pattern

This matches when the regex first matches. Any named captures are bound to variables of the same names.

case "submitted 2020-10-20" of
[regex|(?<y>\d{4})-(?<m>\d{2})-(?<d>\d{2})|] ->
let year = read @Int $ Text.unpack y
...

Note that it is not possible to access the 0th capture this way. As a workaround, explicitly capture the whole pattern and name it. If there are no named captures, this simply acts as a guard.

Make a new regex but abort on an error in the regex string itself.

The TDFA backend specific Regex type, used by this module's RegexOptions and RegexMaker.

A compiled regular expression.

A GRegex is the "compiled" form of a regular expression pattern. GRegex implements regular expression pattern matching using syntax and semantics similar to Perl regular expression. See the PCRE documentation) for the syntax definition. Some functions accept a startPosition argument, setting it differs from just passing over a shortened string and setting RegexMatchFlagsNotbol in the case of a pattern that begins with any kind of lookbehind assertion. For example, consider the pattern "\Biss\B" which finds occurrences of "iss" in the middle of words. ("\B" matches only if the current position in the subject is not a word boundary.) When applied to the string "Mississipi" from the fourth byte, namely "issipi", it does not match, because "\B" is always false at the start of the subject, which is deemed to be a word boundary. However, if the entire string is passed , but with startPosition set to 4, it finds the second occurrence of "iss" because it is able to look behind the starting point to discover that it is preceded by a letter. Note that, unless you set the RegexCompileFlagsRaw flag, all the strings passed to these functions must be encoded in UTF-8. The lengths and the positions inside the strings are in bytes and not in characters, so, for instance, "\xc3\xa0" (i.e. "à") is two bytes long but it is treated as a single character. If you set RegexCompileFlagsRaw the strings can be non-valid UTF-8 strings and a byte is treated as a character, so "\xc3\xa0" is two bytes and two characters long. When matching a pattern, "\n" matches only against a "\n" character in the string, and "\r" matches only a "\r" character. To match any newline sequence use "\R". This particular group matches either the two-character sequence CR + LF ("\r\n"), or one of the single characters LF (linefeed, U+000A, "\n"), VT vertical tab, U+000B, "\v"), FF (formfeed, U+000C, "\f"), CR (carriage return, U+000D, "\r"), NEL (next line, U+0085), LS (line separator, U+2028), or PS (paragraph separator, U+2029). The behaviour of the dot, circumflex, and dollar metacharacters are affected by newline characters, the default is to recognize any newline character (the same characters recognized by "\R"). This can be changed with G_REGEX_NEWLINE_CR, G_REGEX_NEWLINE_LF and G_REGEX_NEWLINE_CRLF compile options, and with G_REGEX_MATCH_NEWLINE_ANY, G_REGEX_MATCH_NEWLINE_CR, G_REGEX_MATCH_NEWLINE_LF and G_REGEX_MATCH_NEWLINE_CRLF match options. These settings are also relevant when compiling a pattern if G_REGEX_EXTENDED is set, and an unescaped "#" outside a character class is encountered. This indicates a comment that lasts until after the next newline. Creating and manipulating the same GRegex structure from different threads is not a problem as GRegex does not modify its internal state between creation and destruction, on the other hand GMatchInfo is not threadsafe. The regular expressions low-level functionalities are obtained through the excellent PCRE library written by Philip Hazel. Since: 2.14

Memory-managed wrapper type.

A compiled regular expression

A compiled regular expression. Regex values are usually constructed using the regex or regex' functions. This type is also an instance of IsString, so if you have the OverloadedStrings language extension enabled, you can construct a Regex by simply writing the pattern in quotes (though this does not allow you to specify any Options).

Regular expression support for Unicode, implemented as bindings to the International Components for Unicode (ICU) libraries. The syntax and behaviour of ICU regular expressions are Perl-like. For complete details, see the ICU User Guide entry at http://userguide.icu-project.org/strings/regexp. Note: The functions in this module are not thread safe. For thread safe use, see clone below, or use the pure functions in Data.Text.ICU.

A compiled regular expression. Regex values are usually constructed using the regex or regex' functions. This type is also an instance of IsString, so if you have the OverloadedStrings language extension enabled, you can construct a Regex by simply writing the pattern in quotes (though this does not allow you to specify any Options).

An abstract pointer to a compiled PCRE Regex structure The structure allocated by the PCRE library will be deallocated automatically by the Haskell storage manager.

The first string is the regex pattern, the second is the regex options string. Options are identified by characters, which must be listed in alphabetical order. Valid options are *i* for case insensitive matching, *m* for multiline matching, *x* for verbose mode, *l* to make \w, \W, etc. locale dependent, *s* for dotall mode ("." matches everything), and *u* to make \w, \W, etc. match unicode.