Struct ConditionStack

pub struct ConditionStack { /* private fields */ }

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.

Implementations

impl ConditionStack

pub fn is_empty(&self) -> bool

pub fn all_true(&self) -> bool

pub fn push_back(&mut self, b: bool)

pub fn pop_back(&mut self) -> Option<()>

pub fn toggle_top(&mut self) -> Option<()>

Trait Implementations

impl Debug for ConditionStack

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ConditionStack

fn default() -> Self

Returns the “default value” for a type.