Text completions with match highlighting

complete.elm

import Debug
import List
import String

type alias Match = {full: String, before: String, match: String, after: String}

score : Match -> Int
score {before} = String.length before

match : String -> String -> Maybe Match
match sub sup =
  case List.head (String.indexes sub sup) of
    Nothing -> Nothing
    Just start ->
      let end = start + String.length sub
      in Just {full = sup,
               before = String.slice 0 start sup,
               match = sub,
               after = String.slice end (String.length sup) sup}

matches : String -> List String -> List Match
matches sub sups =
  List.sort sups |> List.filterMap (match sub) |> List.sortBy score
  
_ = Debug.log "matches" (matches "foo" ["Arfoo","foo","bfoobar","fogey","golf","","fookin"])