elm-generic-dict

elm-generic-dict can be used to codegen dictionaries with arbitrary types as keys. It is meant to be used as a library with elm-codegen.

The dictionaries don't contain functions, and the API (of the generated code) doesn't require you to pass any function.

The main disadvantage of using this approach is code duplication, while the advantages are:

1. does not contain functions (useful for debugging and usage in lamdera),
2. does not require passing in functions when using it (cleaner API, no possibility of mistakes),
3. live code inclusion will trim unused functions.

Example

Say you'd like a Dict of UUID.UUID:

• First, follow elm-codegen's docs, on installing packages
• edit the codegen/Generate.elm to look something like

module Generate exposing (main)

import Elm
import Elm.Annotation as Type
import Gen.CodeGen.Generate as Generate
import Gen.UUID
import GenericDict


main : Program {} () ()
main =
    Generate.run
        [ customDictFile
        ]


customDictFile : Elm.File
customDictFile =
    GenericDict.init
        { keyType = Gen.UUID.annotation_.uUID
        , namespace = []
        , toComparable = Gen.UUID.toString
        }
        |> GenericDict.withTypeName "UuidDict"
        |> GenericDict.generateFile

• run elm-codegen run to have it create the generated/UuidDict.elm
• update your elm.json to include generated/ as a source-directory
• import it as Import UuidDict exposing (UuidDict) to use it like a UuidDict a