Maude-help mailing list

[wilson <wmtan00 AT gmail.com>]

Hello Maude Help,

Is there an existing way of implementing "chained rules" in Maude?

What I basically want is the conditional application of a rule depending 
on the previous application of another rule.

For example

   rl [1] : ... .
   rl [2] : ... .

I want rule 2 to be considered only if 1 was applied previously.

I'm aiming in the long run to be able to "defer" the application of 
rewriting rules. For instance, I want a rule to be applied only on the 
third application possibility found. Thus I would need to count the 
instances the rule could have been applied. In pseudo C formalism, 
something like

   rl [mate-non-applied] :
   {
       equation => equation . --- do nothing
       iterator = iterator + 1
   }

   crl [mate-applied]:
   {
       equation => rewritten equation .
       iterator = 0
   }
   if iterator > 2 .

I must admit, I'm having problems with making the rule "do nothing but 
increment the iterator". I could make the iteration a separate 
conditional rule, but then I can't make it dependent on the 
"application" of the "do nothing" rule(hence, my original question on 
"chained rules").

Could this be done with current Maude? Or do I have to do some tweaking 
with the Maude source code?

Thanks a lot, guys.