#include <stdlib>
#include "cfa-stack.h"

forall(otype T) struct stack_node {
	T value;
	stack_node(T)* next;
};

forall(otype T) void ?{}(stack(T)& s) { (s.head){ 0 }; }

forall(otype T) void ?{}(stack(T)& s, stack(T) t) {
	stack_node(T)** crnt = &s.head;
	for ( stack_node(T)* next = t.head; next; next = next->next ) {
		// *crnt = &(*(stack_node(T)*)malloc()){ next->value }; /***/
		stack_node(T)* new_node = ((stack_node(T)*)malloc());
		(*new_node){ next->value }; /***/
		*crnt = new_node;

		stack_node(T)* acrnt = *crnt;
		crnt = &acrnt->next;
	}
	*crnt = 0;
}

forall(otype T) stack(T) ?=?(stack(T)& s, stack(T) t) {
	if ( s.head == t.head ) return s;
	clear(s);
	s{ t };
	return s;
}

forall(otype T) void ^?{}(stack(T)& s) { clear(s); }

forall(otype T) _Bool empty(const stack(T)& s) { return s.head == 0; }

forall(otype T) void push(stack(T)& s, T value) {
	// s.head = &(*(stack_node(T)*)malloc()){ value, s.head }; /***/
	stack_node(T)* new_node = ((stack_node(T)*)malloc());
	(*new_node){ value, s.head }; /***/
	s.head = new_node;
}

forall(otype T) T pop(stack(T)& s) {
	stack_node(T)* n = s.head;
	s.head = n->next;
	T x = n->value;
	^n{};
	free(n);
	return x;
}

forall(otype T) void clear(stack(T)& s) {
    for ( stack_node(T)* next = s.head; next; ) {
		stack_node(T)* crnt = next;
		next = crnt->next;
		delete(crnt);
	}
	s.head = 0;
}