bug in language definition (strictness)

[Malcolm Wallace]

> If, as I understand it, you are relying on the fact that seq's first  
> argument is evaluted before its second, then you really want pseq  
> rather than seq.
>
> In GHC we provide a way to do what you want (pseq), I'm just not  
> convinced it should be the required behaviour of seq.

Whilst looking for something else, I have discovered that the official  
list of changes from Haskell 1.2 to Haskell 1.3 has this explicit  
statement:

"The seq function evaluates its first argument before returning the  
second one."
         http://haskell.org/definition/from12to13.html

In addition, the 1.3 and 1.4 Reports, in describing how seq should be  
understood for any particular type, states:

"The _case_ is used to force evaluation of the first argument to `seq`  
before returning the second argument."

The Haskell'98 committee decided to remove the Eval class (that had  
seq as one of its methods), see http://www.cs.chalmers.se/~rjmh/Haskell/Messages/Decision.cgi?id=204

I assume that it was simply inattention whilst editing the Report  
text, that caused the removal of the official requirement that seq  
evaluate its first argument before its second, because I can find no  
discussion by the committee that suggested such an important change.

If you can point me to the committee discussion that led to changing  
this requirement, I would be grateful.

Regards,
     Malcolm