[Haskell-cafe] Record updates

[Malcolm Wallace]

> Now suppose that foo3 :: [Int], and I want to prepend 5 to it. I end  
> up having to write something like
>
> let v1 = v0 {foo3 = 5 : (foo3 v0)}

There used to be a feature in pre-Haskell'98 called "named field  
puns", which allows to use a shorter form of field access.  Your  
example would come out as

   f v0{foo3} =
     let v1 = v0 {foo3 = 5: foo3} in ...

Have a look in the Haskell-1.4 Language Report to see how it works.   
The behaviour is still supported as an extension by Hugs (-98), nhc98  
(-puns), and ghc (-XNamedFieldPuns).

Regards,
     Malcolm