[Haskell-cafe] Sending bottom to his room

[Cristian Baboi]

In The Implementation of Functional Programming Languages by S.P. Jones,  
section 2.5.3, page 32 it is written:


Eval [[*]] a b = a x b
Eval [[*]] _|_ b = _|_
Eval [[*]] a _|_ = _|_

but in section 2.5.2 it is said that _|_ is an element of the value domain.
What business does it have on the left side of the '=' ?

Can you help me send him to his room ?