A data type to abstract out the condition stack during script execution. More...

#include <conditionstack.h>

Public Member Functions
bool	empty () const

bool	all_true () const

void	push_back (bool f)

void	pop_back ()

void	toggle_top ()

Private Attributes
uint32_t	m_stack_size = 0
	The size of the implied stack. More...

uint32_t	m_first_false_pos = NO_FALSE
	The position of the first false value on the implied stack, or NO_FALSE if all true. More...

Static Private Attributes
static constexpr uint32_t	NO_FALSE = std::numeric_limits<uint32_t>::max()
	A constant for m_first_false_pos to indicate there are no falses. More...

Detailed Description

A data type to abstract out the condition stack during script execution.

Conceptually it acts like a vector of booleans, one for each level of nested IF/THEN/ELSE, indicating whether we're in the active or inactive branch of each.

The elements on the stack cannot be observed individually; we only need to expose whether the stack is empty and whether or not any false values are present at all. To implement OP_ELSE, a toggle_top modifier is added, which flips the last value without returning it.

This uses an optimized implementation that does not materialize the actual stack. Instead, it just stores the size of the would-be stack, and the position of the first false value in it.

Definition at line 28 of file conditionstack.h.

Member Function Documentation