where fd constraints go

[Hak-Jin Kim]

Hello,

For fd programming, I wonder where fd constraints for problem representation
go.
According to a document, all constraints are entailed to constraint of the
form, X in r, and the constraint store keeps such constraints.  Then where
original constraints go?  They go to 'global stack'?

Also I like to put a different type of constraint such as
 'fd_constraint --> call an imperative function'. Here the fd_constraint is
not affected by consistency checking.  What I need is to check the truth
value.  That is, if the antecedent has true, the imperative function in the
consequence should be executed; otherwise, it is ignored.  Can this kind be
constructed in the current gprolog fd constraint system?

Thirdly, is there any detailed document about the user defined fd constraint
using fd2c?

Any comment will be helpful to me.  Thanks in advance.

hakjin