Example of Nested Routes (with parameters) in Bogdanp/elm-route 4.0.0 and Elm 0.18

gistfile1.txt

module Routes exposing (..)
import Navigation exposing (Location)
import Route exposing (..)
import Combine exposing ((<$),(*>),(<$>))
import Combine.Num

type Sitemap
    = ProfileR String Profile
    | NotFoundR
    
type Profile
    = AboutMe
    | Projects
    | Project Int

show : Profile -> String
show profile =
    case profile of
        AboutMe ->
            ""
        Projects ->
            "projects"
        Project i ->
            "project/" ++ Basics.toString i
            
profile : Combine.Parser s Profile
profile =
    Combine.choice
        [
        -- beware! the order is very important here and one wrong step may mean that the route is never found!
        , Project <$> (Combine.string "project/" *> Combine.Num.int)
        , Projects <$ Combine.string "projects"
        , AboutMe <$ Combine.string ""
        ]
        
profileR =
    ProfileR := static "people" </> string </> custom profile
    

sitemap =
    router [ profileR ]

toString : Sitemap -> String
toString r =
    case r of   
        ProfileR username p ->
            reverse profileR [ username, show p ]

        NotFoundR ->
            Debug.crash "cannot render NotFound"