Test rules to make sure they are valid

[mnapoli]

When a UI is responsible for generating some rules, we need to make sure they are valid (that they will execute correctly). Is there a way to "test" that some rules are valid?

What I thought of is trying to compile them with the compiler that Rulerz uses, but:

• is that enough to make sure they are valid (i.e. no syntax errors)
• in $compiler->compile($rule, $targetCompiler) can I simply use ArrayVisitor (most basic one) or do I need to set up something more complex?

And finally would it make sense to add that to Rulerz directly?

[mnapoli]

What I did for now and that seems to work:

        try {
            $this->rulerzCompiler->compile($rules, new ArrayVisitor);
        } catch (UnexpectedToken $e) {
            throw new InvalidRules('Invalid promotion rules: ' . $rules, 0, $e);
        }

[K-Phoen]

Is there a way to "test" that some rules are valid?

To consider a rule as "valid", it must:

• be syntactically correct
• use only existing operators
• use only existing variables/accesses

I've already implemented these verifications in wallabag to check that the tagging rules written by users are valid.

I've written a RuleValidator that compiles the rule, and I use the resulting model to check that all the used variables and operators are allowed. As there is no way to automatically know which variables and operators are allowed, I used a whitelist.

[K-Phoen]

@mnapoli do you need additional input on this?

[mnapoli]

Nope thanks, we've used the trick I shown above for now.