Examples with Decl edu.mit.csail.sdg.ast.Decl used on opensource projects

Example 11 with Decl

use of edu.mit.csail.sdg.ast.Decl in project org.alloytools.alloy by AlloyTools.

the class DemoFileSystem method makeDomain.

void makeDomain() throws Err {
    // abstract sig Obj { parent: lone Dir }
    // abstract sig Dir extends Obj { contains: set Obj }
    // abstract sig File extends Obj { }
    // one sig Root extends Dir { }
    obj = makeSig("Obj", true, false);
    dir = makeSig(obj, "Dir", true, false);
    file = makeSig(obj, "File", true, false);
    root = makeSig(dir, "Root", false, true);
    parent = obj.addField("parent", dir.loneOf());
    contains = dir.addField("contains", obj.setOf());
    // fact { all x:Obj-Root | one x.parent }
    Decl x = obj.minus(root).oneOf("x");
    fact = x.get().join(parent).one().forAll(x).and(fact);
    // fact { contains = ~ parent }
    fact = contains.equal(parent.transpose()).and(fact);
    // fact { acyclic[contains] }
    fact = acyclic(contains).and(fact);
}

Example 12 with Decl

use of edu.mit.csail.sdg.ast.Decl in project org.alloytools.alloy by AlloyTools.

the class DemoFileSystem method acyclic.

/*
     * These corresponds to the helper predicates/functions provided in util/*.als
     */
static Expr acyclic(Expr r) throws Err {
    // x is a variable over the domain
    Decl d = r.join(Sig.UNIV).oneOf("x");
    // of r
    ExprHasName x = d.get();
    // (x !in x.^r) for
    return x.in(x.join(r.closure())).not().forAll(d);
// all x
}