Documentation

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"))