Text.Regex.Applicative

Documentation

data RE s a

Type of regular expressions that recognize symbols of type s and produce a result of type a.

Regular expressions can be built using Functor, Applicative and Alternative instances in the following natural way:

• f <$> ra matches iff ra matches, and its return value is the result of applying f to the return value of ra.
• pure x matches the empty string (i.e. it does not consume any symbols), and its return value is x
• rf <*> ra matches a string iff it is a concatenation of two strings: one matched by rf and the other matched by ra. The return value is f a, where f and a are the return values of rf and ra respectively.
• ra <|> rb matches a string which is accepted by either ra or rb. It is left-biased, so if both can match, the result of ra is used.
• empty is a regular expression which does not match any string.
• many ra matches concatenation of zero or more strings matched by ra and returns the list of ra's return values on those strings.

Instances

Functor (RE s)

Applicative (RE s)

Alternative (RE s)

sym :: Eq s => s -> RE s s

Matches and returns the given symbol

psym :: (s -> Bool) -> RE s s

Matches and returns a single symbol which satisfies the predicate

anySym :: RE s s

Matches and returns any single symbol

reFoldl :: (b -> a -> b) -> b -> RE s a -> RE s b

Greedily matches zero or more symbols, which are combined using the given folding function

(=~) :: [s] -> RE s a -> Maybe a

Attempts to match a string of symbols against the regular expression

module Control.Applicative