CompositionExample.elm

bang : String -> String
bang str =
    str ++ “!”


uppercase : String -> String
uppercase str =
    String.toUpper str


{-| Simple Function 

in this function we're adding a couple of exclamation marks and
uppercasing as you can see, with all those parens it’s a bit noisy
-}
shout : String -> String
shout str =
    uppercase (bang (bang str))


{-| Returned Lambda Example 

we can change it to return a new function instead using lambda
notation (anonymous function) this is even worse than previously
for noise, but sort of explains what is going to happen next
-}
shout': String -> String
shout' =
   (\str -> uppercase(bang (bang str)))


{-| Function Composition Example

the above version essentially doing the same thing as this,
though now we don’t have the ugly floating variable or parens
-}
shout'' : String -> String
shout'' =
    uppercase << bang << bang


{-| Pipe Syntax Example

elm also offers another nice way of composing functions into a
pipeline, which some people find easier to read as it more closely
resembles chaining in oop langauges like js and ruby, and also the
pipe operator `|` in shell scripting.
-}
shout''' : String -> String
shout''' str =
    str
    |> uppercase
    |> bang
    |> bang