//var unify = require('unify');

var variable = unify.variable;

var isNum = function(o){return typeof(o) == "number";};

var expr1 = unify.box([variable("X", isNum),1]);

var expr2 = unify.box(["string",1]);

var expr3 = unify.box([1,1]);

if (expr1.unify(expr2)) {

  console.log("Unification successful! X=" + expr1.get("X").toString());

}

else {

  console.log("Unification unsuccessful!");

}

if (expr1.unify(expr3)) {

  console.log("Unification successful! X=" + expr1.get("X").toString());

}

else {

  console.log("Unification unsuccessful!");

}

//The following should be written to the console

//Unification unsuccessful!

//Unification successful! X=1