Re: [Haskell-cafe] type inference and named fields

On Thu, 23 Jun 2005, Christian Maeder wrote:

Malcolm Wallace wrote:

...

...

voidcast :: Fields a -> Fields Void voidcast v@(VariantWithTwo{}) = v { field1 = Void , field2 = Void } voidcast v@(VariantWithOne{}) = v { field1 = Void }

I would not expect that updating only field1 can change the type of v. The right thing is to construct a new value. This looks as follows with record syntax:

voidcast VariantWithTwo{} = VariantWithTwo { field1 = Void , field2 = Void } voidcast VariantWithOne{} = VariantWithOne { field1 = Void }

Erm, I have overlooked this, too. So my update function proposal doesn't affect the type aspect of record update syntax.