match on a specific string

match on any string

apply a function to the remainder of the segments

useful if you want to just do normal pattern matching: > > foo ["foo", "bar"] = Right (Foo Bar) > foo ["baz"] = Right Baz > foo _ = Left "parse error"

patternParse foo

run a URLParser on a list of path segments

returns Left "parse error" on failure.

returns Right a on success

Simple parsing and rendering for a type to and from URL path segments.

If you're using GHC 7.2 or later, you can use DeriveGeneric to derive instances of this class:

{-# LANGUAGE DeriveGeneric #-}
data Sitemap = Home | BlogPost Int deriving Generic
instance PathInfo Sitemap

This results in the following instance:

instance PathInfo Sitemap where
    toPathSegments Home = ["home"]
    toPathSegments (BlogPost x) = "blog-post" : toPathSegments x
    fromPathSegments = Home <$ segment "home"
                   <|> BlogPost <$ segment "blog-post" <*> fromPathSegments

And here it is in action:

>>> toPathInfo (BlogPost 123)
"/blog-post/123"
>>> fromPathInfo "/blog-post/123" :: Either String Sitemap
Right (BlogPost 123)

To instead derive instances using TemplateHaskell, see web-routes-th.

convert url into the path info portion of a URL

convert url + params into the path info portion of a URL + a query string

parse a String into url using PathInfo.

returns Left "parse error" on failure

returns Right url on success

turn a routing function into a Site value using the PathInfo class

show Parsec ParseError using terms that relevant to parsing a url

Representable types of kind *. This class is derivable in GHC with the DeriveGeneric flag on.