arena

Documentation

Overview

Package arena is a bump allocator with a linked list of fixed-size blocks. It mirrors cpython/Python/pyarena.c and serves the compiler pipeline (parser, AST, symtable, codegen) where many small nodes share a single lifetime.

The arena is not safe for concurrent use. Callers serialize externally, the same as CPython.

Index

• type Arena
  • func New() *Arena
  • func (a *Arena) AddObject(obj any) error
  • func (a *Arena) Free()
  • func (a *Arena) Malloc(n int) []byte

Types

type Arena

type Arena struct {
	// contains filtered or unexported fields
}

Arena is a bump allocator. The zero value is not usable; call New.

CPython: Python/pyarena.c:L43 _arena

func New

func New() *Arena

New returns an arena with one preallocated block.

CPython: Python/pyarena.c:L125 _PyArena_New

func (*Arena) AddObject

func (a *Arena) AddObject(obj any) error

AddObject registers obj so it is retained until Free is called. The error return mirrors the C call shape; in practice the value is always nil.

CPython: Python/pyarena.c:L200 _PyArena_AddPyObject

func (*Arena) Free

func (a *Arena) Free()

Free drops every block and tracked object, so the GC can reclaim them. The arena must not be used after Free.

CPython: Python/pyarena.c:L154 _PyArena_Free

func (*Arena) Malloc

func (a *Arena) Malloc(n int) []byte

Malloc returns a byte slice of length n carved out of the current block, allocating a new block if needed. The slice is capped so callers cannot append into the next allocation. n is rounded up to the alignment boundary; the returned slice has the rounded length, matching what _PyArena_Malloc hands out in C.

CPython: Python/pyarena.c:L177 _PyArena_Malloc