Update whole Component.Set

Single component mapping, Same asList.map - only for Component.Set inside World

gravitySystem =
    Logic.System.step (Vec2.add gravity) accelerationSpec

Step over all entities that have both components.

Example:

system =
    Logic.System.step2
        (\( v, _ ) ( p, setP ) -> setP (Vec2.add v p))
        velocitySpec
        positionSpec

Same as step2 only with 3 components

Same as step2 only with 4 components

Same as step2 only with 5 components

Reduce an Component.Set from the left.

Example count how much enemies left in world:

enemySet =
    enemySpec.get world


count =
    foldl (\_ -> (+) 1) enemySet 0

Step over all entities that have both components and reduce an Component.Sets from the left.

Same as foldl2 only with 3 components

Same as foldl2 only with 4 components

Same as foldl2 only with 5 components

Variant of foldl that passes the index of the current element to the step function.

indexedFoldl is to foldl as List.indexedMap is to List.map.

Same as indexedFoldl2 only with 3 components

Same as indexedFoldl2 only with 4 components

Same as indexedFoldl2 only with 5 components

Just nice helper function to pipe into systems

update msg world =
    world
        |> system1
        |> applyIf (msg === KeyUp "a") systemMoveLeft
        |> system2

Same as applyIf, but works with Maybe

update msg world =
    world
        |> system1
        |> applyMaybe (decode saveDecoder msg) loadGame
        |> system2