Struct passerine::vm::VM

pub struct VM {
    pub closure: Closure,
    pub stack: Stack,
    pub ip: usize,
}

A VM executes bytecode lambda closures. (That’s a mouthful - think bytecode + some context). VM initialization overhead is tiny, and each VM’s state is self-contained, so more than one can be spawned if needed.

Fields

closure: Closure

stack: Stack

ip: usize

Implementations

impl VM

pub fn init(closure: Closure) -> VM

Initialize a new VM. To run the VM, a lambda must be passed to it through run.

pub fn next(&mut self)

Advances to the next instruction.

pub fn done(&mut self) -> Result<(), Trace>

Advances IP, returns Ok. Used in Bytecode implementations.

pub fn peek_byte(&mut self) -> u8

Returns the current instruction as a byte.

pub fn next_byte(&mut self) -> u8

Advances IP and returns the current instruction as a byte.

pub fn is_terminated(&mut self) -> bool

Returns whether the program has terminated

pub fn next_number(&mut self) -> usize

Builds the next number in the bytecode stream. See utils::number for more.

pub fn current_span(&self) -> Span

pub fn step(&mut self) -> Result<(), Trace>

Dissasembles and interprets a single (potentially fallible) bytecode op. The op definitions follow in the next impl block. To see what each op does, check common::opcode::Opcode.

pub fn unwind(&mut self)

pub fn run(&mut self) -> Result<(), Trace>

Suspends the current lambda and runs a new one on the VM. Runs until either success, in which it restores the state of the previous lambda, Or failure, in which it returns the runtime error. In the future, fibers will allow for error handling - right now, error in Passerine are practically panics.

pub fn con(&mut self) -> Result<(), Trace>

Load a constant and push it onto the stack.

pub fn not_init(&mut self) -> Result<(), Trace>

pub fn capture(&mut self) -> Result<(), Trace>

Moves the top value on the stack to the heap, replacing it with a reference to the heapified value.

pub fn save(&mut self) -> Result<(), Trace>

Save the topmost value on the stack into a variable.

pub fn save_cap(&mut self) -> Result<(), Trace>

Save the topmost value on the stack into a captured variable.

pub fn load(&mut self) -> Result<(), Trace>

Push a copy of a variable’s value onto the stack.

pub fn load_cap(&mut self) -> Result<(), Trace>

Load a captured variable from the current closure.

pub fn del(&mut self) -> Result<(), Trace>

Delete the top item of the stack.

pub fn copy_val(&mut self) -> Result<(), Trace>

Copy the top data of the stack, i.e. [F, D] becomes [F, D, D].

pub fn print(&mut self) -> Result<(), Trace>

pub fn label(&mut self) -> Result<(), Trace>

pub fn tuple(&mut self) -> Result<(), Trace>

pub fn call(&mut self) -> Result<(), Trace>

Call a function on the top of the stack, passing the next value as an argument.

pub fn return_val(&mut self) -> Result<(), Trace>

Return a value from a function. End the execution of the current lambda. Takes the number of locals on the stack Relpaces the last frame with the value on the top of the stack. Expects the stack to be a [..., Frame, Local 1, ..., Local N, Data]

pub fn closure(&mut self) -> Result<(), Trace>

pub fn ffi_call(&mut self) -> Result<(), Trace>

Trait Implementations

impl Debug for VM

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

Formats the value using the given formatter.