// TODO: The method apply() should be defined in class Node
// to report an error. It should be overridden only in classes
// BuiltIn and Closure.
/*
* Before calling the function apply, its arguments are evaluated
* the first argument must be a closure, then apply needs todo
* extract the environment out of the closure
* add a new frame to the environment that binds the parameters
* to the corresponding argument values
* recursively call eval for the function body and the new enviornment
*
*/
public override Node apply(Node args)
{
//need to get both args
Node arg1 = args.getCar(), arg2 = args.getCdr();
//need to see if arg1 is a Closure
if (arg1.isProcedure())
{
//getting the environment out of the Closure arg1
Environment newEnv = ((Closure)arg1).getEnv();
//adding a new frame to the environment
newEnv.define(((Closure)arg1).getFun(), arg2);
//trying to recursively call eval
newEnv.eval(newEnv);
//return environment?
return(newEnv);
}
else
{
return(new StringLit("Error: apply on non closure"));
}
}
