Struct brane_exe::frame_stack::FrameStack

pub struct FrameStack { /* private fields */ }

Implements a FrameStack, which is used to keep track of function calls and their expected return types.

Implementations

impl FrameStack

pub fn new(size: usize, table: Arc<SymTable>) -> Self

Constructor for the FrameStack, which initializes it with the given size.

Arguments

• size: The size of the FrameStack.
• table: The global scope to start with what (and what variables are) is in scope.

Returns

A new FrameStack instance.

pub fn fork(&self) -> Self

Forks the framestack, which copies the existing variables in-scope into a single frame that is the new main.

Returns

A new FrameStack instance that can be used in a forked thread.

pub fn update_table(&mut self, table: Arc<SymTable>)

Updates the internal table to be the same as the given one.

This is useful if the workflow is updating its own states.

Arguments

• table: The new table to use as ground truth.

Returns

Nothing, but does update the internal table.

pub fn push(&mut self, def: usize, ret: ProgramCounter) -> Result<(), Error>

Pushes a new Frame onto the FrameStack.

Arguments

• def: The function to create a new frame for.
• ret: The return address (pair) to return to.

Returns

Nothing, but does set it internally.

Errors

This function may error if the FrameStack overflows.

pub fn pop(&mut self) -> Result<(ProgramCounter, DataType), Error>

Pops the top value off of the FrameStack, returning the expected data type and return address.

Returns

A ProgramCounter denoting the return address and expected return type, respectively. If the main was popped, however, then the return address is (usize::MAX, usize::MAX).

Errors

This function may error if there was nothing left on the stack.

pub fn declare(&mut self, def: usize) -> Result<(), Error>

Declares a variable with the given index.

Arguments

• def: The variable to declare.

Returns

Nothing, but does allow the variable to have a value from this point onwards.

Errors

This function may error if the given definition is unknown.

pub fn undeclare(&mut self, def: usize) -> Result<(), Error>

Undclares a variable with the given index, effectively brining it back to uninitialized status.

Arguments

• def: The variable to undeclare.

Returns

Nothing, but does require the variable to be declared before it can be used.

Errors

This function may error if the given definition is unknown.

pub fn set(&mut self, def: usize, value: Value) -> Result<(), Error>

Sets the variable with the given index to the given Value.

Arguments

• def: The variable to set.
• value: The new Value to set it to.

Returns

Nothing, but does update the given variable’s value.

Errors

This function may error if there was nothing left on the stack or if the given variable was not declared.

pub fn get(&self, def: usize) -> Result<&Value, Error>

Gets the value of the variable with the given index.

Arguments

• def: The variable to get.

Returns

The current value of the variable.

Errors

This function may error if there was nothing left on the stack or if the given variable was not declared.

pub fn capacity(&self) -> usize

Returns the total capacity of the FrameStack. Using any more than this will result in overflows.

pub fn is_empty(&self) -> bool

Returns if the framestack is currently empty.

pub fn len(&self) -> usize

Returns the number of frames currently on the FrameStack.

pub fn table(&self) -> &SymTable

Returns the internal table.

Trait Implementations

impl Clone for FrameStack

fn clone(&self) -> FrameStack

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FrameStack

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

Formats the value using the given formatter.