module build_constraint

// evaluating the AST nodes, in the given environment
fn (b BExpr) eval(env &Environment) !bool {
    return b.expr.eval(env)
}

fn (b BOr) eval(env &Environment) !bool {
    for e in b.exprs {
        if e.eval(env)! {
            return true
        }
    }
    return false
}

fn (b BAnd) eval(env &Environment) !bool {
    for e in b.exprs {
        if !e.eval(env)! {
            return false
        }
    }
    return true
}

fn (b BUnary) eval(env &Environment) !bool {
    match b {
        BNot, BExpr, BFact, BDefine { return b.eval(env)! }
    }

    return false
}

fn (b BNot) eval(env &Environment) !bool {
    return !b.expr.eval(env)!
}

fn (b BFact) eval(env &Environment) !bool {
    return env.is_fact(b)
}

fn (b BDefine) eval(env &Environment) !bool {
    return env.is_define(b)
}