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Specify options for controlling ech compilation
- Option Name (Atom)
- If Option should be on ('on') or off ('off'), or an integer between 1 and 11
Allows the user to set options that affect the way the CHRs are compiled.
These options can be turned on or off, with the default state being on.
The options controls if certain run-time safety checks are performed or
not. With the option off, the associated safety check will not be generated
for the CHR code when compiled. Such code can run more efficiently, but
can lead to incorrect behaviour that the checks would have been able to
- When executing a guard in a CHR rule, checks are performed
so that if a guard goal attemps to touch a global variable (i.e. a
variable which occurs in the rule head), the guard will fail. With
this option set to `off', then the checks are not performed.
- Before adding a user-defined CHR constraint to the constraint
store, a check is performed to see if the particular constraint
(i.e. with exactly the same variables) is already in the store.
If this option is set to `off', then the check is not performed.
The user can explicitly check if a constraint is in store by the
- On_or_Off is an integer between 1 and 11, specifying the
default priority for CHR constraints generated by the compiler.
It also specifies the priority that at_lower/at_higher
declarations will be calculated from in the constraints/1
declarations. Note that all priorities are determined at the
point of the constraint declaration and is not affected by any
subsequent changes in chr_priority.
This predicate is sensitive to its module context (tool predicate, see @/2).