Я ☞ Primitives ☞ Progress

Supertype (Progress error item) ~ error S item

Aliases: Error, Probably

   Continue: item `AR_` Progress error item
Intrerrupt: error `AR_` Progress error item
     Error: error `AR_` Progress error item
  Valid: item `AR_____` Progress error item
   Ok: item `AR_______` Progress error item

Could be rewrapped to a Boolean, Optional since it’s a Sum.

Useful for computations that could be interrupted by errors:

Valid _ `yo` Valid `AR__` Valid (Valid _)
Valid _ `yok` Try `ha` Valid `AR___` Valid _
Error _ `yok` Try `ha` Valid `AR___` Error _
Valid _ `yok` Try `ha` Error `AR___` Error _

Can be used as a jointed effect with State.

State _ `JNT` Error