openscad-evaluator 1.0.0

An AST evaluator for the OpenSCAD language, producing Manifold CSG geometry from a parsed AST.

openscad_evaluator

An AST evaluator for the OpenSCAD language, producing Manifold CSG geometry from a parsed AST.

Overview

openscad_evaluator takes an OpenSCAD AST — as produced by openscad_lalr_parser — and walks it to produce Manifold meshes: a two-pass resolve (AST walk, no CSG calls) then generate (bottom-up Manifold/CrossSection construction) pipeline, with $fn/$fa/$fs, full built-in coverage (primitives, transforms, boolean ops, 2D geometry, text(), surface(), DXF/3MF import, roof()), and a content-hash geometry cache (ManifoldCache) so repeated renders/debugger pauses skip unchanged Manifold work.

It's GUI- and toolkit-agnostic: the only way it talks back to a caller is a handful of optional callback parameters on Evaluator.__init__ (echo_fn, debug_hook, error_break_fn, return_hook) — no QObject, no signals, no direct rendering. This is the evaluator that powers BelfrySCAD.

See docs/evaluator.md for the full architecture reference: scope processing, assignment order, the built-ins table, 2D/3D geometry handling, error format, $variables scoping, include/use, and the Manifold provenance / AST-to-geometry-ID mapping used for WYSIWYG picking.

Installation

pip install openscad-evaluator

For DXF import support:

pip install openscad-evaluator[dxf]

From Source

git clone https://github.com/BelfrySCAD/openscad_evaluator.git
cd openscad_evaluator
pip install -e ".[dev]"

Quick Start

from openscad_lalr_parser import getASTfromString, build_scopes
from openscad_evaluator import Evaluator

nodes = getASTfromString("cube([10, 10, 10]);")
root_scope = build_scopes(nodes)

ev = Evaluator()
bodies, id_to_node = ev.evaluate(nodes, root_scope)
for body in bodies:
    print(body.body.num_tri(), "triangles")

Development

uv sync --all-extras
uv run pytest