Creating `Atom`s

[peacememories]

We're using the rust clingo bindings to generate grounded programs that we would then like to solve with a few facts added as assumptions. the assumptions argument of Control::solve seems like the way to go, but I can't find any way to generate a Literal or Atom, from a Symbol or otherwise. I would greatly appreciate any advice :)

[sthiele]

I think the best way would be to use the ProgramBuilder for that.

...
    let mut ctl = Control::new(options).expect("Failed creating Control.");
    let mut builder = ast::ProgramBuilder::from(self.control).unwrap();

    let sym = Symbol::create_id("test", true).unwrap();
    let term = Term::from(sym);
    let lit = ast::Literal::from_term(Sign::None, &term);
    let hlit = HeadLiteral::from(&lit);
    let rule = Rule::new(hlit, &[]);
    let stmt = rule.ast_statement();

    // add the rewritten statement to the program
    builder
        .add(&stmt)
        .expect("Failed to add statement to ProgramBuilder.");

Also see the ast example.

[peacememories]

I'm guessing i'd need to ground the program again afterwards? Sorry for these naive questions, I'm not really familiar with clingo yet^^'

[sthiele]

Yes ProgramBuilder is used before grounding. After grounding you could get the SymbolicAtoms and then use the method literal().

Also see the symbolic atoms example.

[peacememories]

Thanks for clearing up my confusion :) I’m going to close this, since it’s not an issue with the library :)