Struct RegChunk 

pub struct RegChunk {
    pub name: String,
    pub code: Vec<RegOp>,
    pub constants: Vec<Value>,
    pub n_regs: u16,
    pub param_slots: u16,
    pub arity: usize,
    pub required: usize,
}

A register-mode chunk (function body), i.e. one frame layout.

Three different quantities used to share one field: the frame’s window size, the count of parameter slots to reserve at the bottom of the frame, and the declared parameter count. They are kept apart here because they answer different questions and only happen to coincide for a plain function:

• RegChunk::n_regs - how many registers the frame needs (window size);
• RegChunk::param_slots - how many of them are reserved for the parameters and an implicit this (the translator’s initial stack height);
• RegChunk::arity / RegChunk::required - the parameter-count contract from the chunk’s FunctionObj, used to check a call.

Fields

name: String

code: Vec<RegOp>

constants: Vec<Value>

n_regs: u16

Registers the frame must allocate: the highest register index any instruction of the chunk uses, plus one.

param_slots: u16

Registers reserved at the bottom of the frame for parameters and an implicit this: this is the translator’s initial stack height, so the chunk’s own let/var locals and every expression temp live at param_slots..n_regs.

It is not the declared parameter count and it is not the function’s arity: a method reserves an extra slot for this, and a chunk reached through CallDirect has no FunctionObj to ask.

arity: usize

Declared parameter count (max) of the chunk’s FunctionObj, used for the arity check when the call site holds the function value. Stays 0 for chunks that only CallDirect reaches.

required: usize

Declared required-parameter count, as RegChunk::arity.

Implementations

impl RegChunk

pub fn new(name: impl Into<String>) -> Self

Trait Implementations

impl Clone for RegChunk

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RegChunk

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

Formats the value using the given formatter.