[Haskell-cafe] howto catamorph monoid (was Re: Is there already an abstraction for this?

On 10/18/08 16:48, Larry Evans wrote: [snip]

I'm trying to apply this to a simple boolean simplifier shown in the attachment. This attachment is the same as the previous except, instead of a boolean algebra, an monoid is used. [snip] The output of the last line of attachment is:

[snip] mon_eval:1*1*v0=(:*) (Op0 (OpCon MonoidOne)) (Op0 (OpVar V0))

however, what I want is a complete reduction to:

(OpVar V0)

As in the previous line beginning with mon_eval: mon_eval:1*v0=Op0 (OpVar V0)

How can this be done using catamorphisms?

Same question w.r.t. this attachment. TIA. -Larry