Stack class

[cavalab]

Stack class

[tilakhere]

commit 40f28e4

Since overloading operator[] could not guarantee different return types hence instead of stack['f'] or stack['b'], stack.f and stack.b are supported.

[lacava]

Some questions and comments on 40f28e4 :

• Can you do ArrayXb x = stack.pop() and have it return an element from the correct stack?
• It would be nice to wrap the stack/node check into a Stack class method. so that
  (stack.f.size() >= n->arity['f'] && stack.b.size() >= n->arity['b'])
  would become something like stack.check(n) and you could define
  bool Stack::check(Node & n) { return stack.f.size() >= n->arity['f'] && stack.b.size() >= n->arity['b'];}
  then we could update the check function in one place as we add /change the stacks.
• the stack name "l" is not nice .. it's hard to read lower case l names. please rename it to 'z' or 'long'.
• for most simple functions (like add) we can simplify the code from

ArrayXd x2 = stack.f.pop();
ArrayXd x1 = stack.f.pop();
stack.f.push(limited(x1 + x2));

to stack.f.push(limited(stack.f.pop() + stack.f.pop()));

[tilakhere]

@lacava

commit 409c0dd

• ArrayXb x = stack.pop() cannot be implemented to return element from correct stack as we need to specify return type in pop() function definition which cannot be generic. Thats why implemented stack.f, stack.b and stack.z. Let me know if you can think of a way this can be improved.

• stack.check(arity) method implemented. Instead of using the whole Node& have used node->arity data member reference as parameter as then stack class would depend on node class and node already is dependent on stack class which would create a cyclic dependency.

• replaced stack.l with stack.z everywhere

• simplified nodes' evaluate() and eval_eqn()

[lacava]

PR #94 merges this into master