Simple TheCocktailDB example

bigos · October 17, 2025, 2:15pm

Now and then I try to make progress with PureScript. While I do not buy the condemnation of Elm, I see situations where I could benefit from PureScript. During my last attempt to make progress with PureScript I managed to figure out how to use flags and send POST requests. This time I want to create a simple client for https://www.thecocktaildb.com/ .
After the initial rage of coming back to PureScript after a while, and encountering the infamous error messages, I persevered and got the flags working again.

github.com

bigos/trying-elm-ui/blob/7175fad56c929d58bdf0c7dcedc4c31fd78fd153/vendor/purescript/cocktails/src/App/Cocktails.purs#L16


      
          import Halogen.HTML.Events as HE
          import Data.Int (fromString)
          import Data.Maybe (Maybe, fromMaybe)
          import Data.String (joinWith)
          
          
type State =
            { count :: Int
            , flags :: Flags
            }
          
          
type Flags =
            { start :: Maybe String
            , logname :: Maybe String
            , base_url :: Maybe String
            }
          
          
data Action = Increment
          
          
initialState :: Flags -> State
          initialState flags =
            { count:

I was impressed by quick progress of the Elm example

github.com

bigos/trying-elm-ui/blob/7175fad56c929d58bdf0c7dcedc4c31fd78fd153/vendor/elm/cocktails/src/Cocktails.elm#L121


      
                          |> Maybe.withDefault Element.none
                      ]
          
          

          
clearButton : Select.ClearButton msg
          clearButton =
              Select.clearButton [ Element.alignRight, Element.centerY, Element.moveLeft 12 ]
                  (Element.el [ Font.size 10, Region.description "clear selection" ] (Element.text "❌"))
          
          

          
drinkView : Cocktail -> Element Msg
          drinkView cocktail =
              Element.column
                  [ Element.spacing 30
                  , Font.size 20
                  , Background.color (Element.rgb 0.9 0.9 0.9)
                  , Element.padding 40
                  , Border.rounded 10
                  ]
                  [ Element.el
                      [ Font.bold

And would like to achieve something similar this time, and perhaps see how far I could go trying to improve over the elm example.

Has anybody done something similar that can be used as an example?

bigos · October 18, 2025, 3:22am

github.com

bigos/trying-elm-ui/blob/master/vendor/purescript/cocktails/src/App/Cocktails.purs

module App.Cocktails where

import Prelude

-- import Affjax.RequestBody as AXRB
import Data.Argonaut (decodeJson)
-- import Data.Argonaut.Core (Json)
import Data.Argonaut.Decode.Error (printJsonDecodeError)
import Data.Array as DA
import Data.Generic.Rep (class Generic)
import Data.List (List, length)
-- import Data.Show (show)
import Data.Show.Generic (genericShow)
-- import Data.String (joinWith)
-- import Data.String as DS
-- import Data.String.Utils (endsWith)
import Effect.Aff.Class (class MonadAff)
-- import Halogen.Component (Component)
-- import Halogen.HTML.Core (HTML)
import Affjax.ResponseFormat as AXRF

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little progress

bigos · October 18, 2025, 11:19am

To what extent should I ignore function signatures? There are situations where they are not helpful at all and send you down the wrong path. The compiler is unable to suggest a type signature that will allow the code to compile.

The example:
https://purescript-halogen.github.io/purescript-halogen/guide/03-Performing-Effects.html
is not helpful.

The imports do not show how to use H.HalogenM
How many of those examples are wrong? What is the point of having type signatures in some places and is there a way to suppress the missing type signatures?

garyb · October 18, 2025, 5:52pm

I value type signatures rather highly. I write them before writing implementations, doing so helps me think about what the code is going to need in terms of inputs and what shape I want the output to be. It then also acts as a check to see if what I’ve done is what I intended to do, while I’m working on the implementation.

bigos · October 18, 2025, 6:17pm

They are useful, where they are useful. But at times, they give me nonsense and prevent me from compiling the code.

How should I handle the contradictions? How much should I battle the type signatures before giving up?