From 29c90a625b40ef9558310e3316867ad7d0eaab86 Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Wed, 11 Mar 2026 11:15:48 +0000
Subject: [PATCH] Delete evaluator.py shim: all imports go directly to
 bootstrapped sx_ref.py

EvalError moved to types.py. All 27 files updated to import eval_expr,
trampoline, call_lambda, etc. directly from shared.sx.ref.sx_ref instead
of through the evaluator.py indirection layer. 320/320 spec tests pass.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 shared/sx/__init__.py                |  7 +--
 shared/sx/async_eval.py              | 21 ++++---
 shared/sx/evaluator.py               | 94 ----------------------------
 shared/sx/handlers.py                |  5 +-
 shared/sx/html.py                    |  2 +-
 shared/sx/jinja_bridge.py            |  5 +-
 shared/sx/pages.py                   |  2 +-
 shared/sx/parser.py                  |  2 +-
 shared/sx/query_registry.py          |  4 +-
 shared/sx/ref/bootstrap_test.py      |  2 +-
 shared/sx/ref/platform_py.py         |  2 +-
 shared/sx/ref/reader_z3.py           |  6 +-
 shared/sx/ref/run_js_sx.py           |  4 +-
 shared/sx/ref/run_py_sx.py           |  4 +-
 shared/sx/ref/sx_ref.py              |  2 +-
 shared/sx/resolver.py                |  2 +-
 shared/sx/tests/run.py               |  2 +-
 shared/sx/tests/test_bootstrapper.py |  2 +-
 shared/sx/tests/test_deps.py         |  2 +-
 shared/sx/tests/test_io_detection.py |  2 +-
 shared/sx/tests/test_io_proxy.py     |  4 +-
 shared/sx/tests/test_page_data.py    | 14 ++---
 shared/sx/tests/test_parity.py       |  6 +-
 shared/sx/tests/test_sx_js.py        |  2 +-
 shared/sx/tests/test_sx_spec.py      |  2 +-
 shared/sx/types.py                   |  9 +++
 sx/sxc/pages/helpers.py              | 14 ++---
 27 files changed, 65 insertions(+), 158 deletions(-)
 delete mode 100644 shared/sx/evaluator.py

diff --git a/shared/sx/__init__.py b/shared/sx/__init__.py
index 20d357c8..9322cfb2 100644
--- a/shared/sx/__init__.py
+++ b/shared/sx/__init__.py
@@ -31,11 +31,8 @@ from .parser import (
     parse_all,
     serialize,
 )
-from .evaluator import (
-    EvalError,
-    evaluate,
-    make_env,
-)
+from .types import EvalError
+from .ref.sx_ref import evaluate, make_env
 
 from .primitives import (
     all_primitives,
diff --git a/shared/sx/async_eval.py b/shared/sx/async_eval.py
index beccab34..78c8e526 100644
--- a/shared/sx/async_eval.py
+++ b/shared/sx/async_eval.py
@@ -53,7 +53,8 @@ from .types import Component, Island, Keyword, Lambda, Macro, NIL, Symbol
 _expand_components: contextvars.ContextVar[bool] = contextvars.ContextVar(
     "_expand_components", default=False
 )
-from .evaluator import _expand_macro, EvalError
+from .ref.sx_ref import expand_macro as _expand_macro
+from .types import EvalError
 from .primitives import _PRIMITIVES
 from .primitives_io import IO_PRIMITIVES, RequestContext, execute_io
 from .parser import SxExpr, serialize
@@ -420,23 +421,23 @@ async def _asf_define(expr, env, ctx):
 
 
 async def _asf_defcomp(expr, env, ctx):
-    from .evaluator import _sf_defcomp
-    return _sf_defcomp(expr, env)
+    from .ref.sx_ref import sf_defcomp
+    return sf_defcomp(expr[1:], env)
 
 
 async def _asf_defstyle(expr, env, ctx):
-    from .evaluator import _sf_defstyle
-    return _sf_defstyle(expr, env)
+    from .ref.sx_ref import sf_defstyle
+    return sf_defstyle(expr[1:], env)
 
 
 async def _asf_defmacro(expr, env, ctx):
-    from .evaluator import _sf_defmacro
-    return _sf_defmacro(expr, env)
+    from .ref.sx_ref import sf_defmacro
+    return sf_defmacro(expr[1:], env)
 
 
 async def _asf_defhandler(expr, env, ctx):
-    from .evaluator import _sf_defhandler
-    return _sf_defhandler(expr, env)
+    from .ref.sx_ref import sf_defhandler
+    return sf_defhandler(expr[1:], env)
 
 
 async def _asf_begin(expr, env, ctx):
@@ -599,7 +600,7 @@ async def _asf_reset(expr, env, ctx):
             _ASYNC_RESET_RESUME.append(value if value is not None else NIL)
             try:
                 # Sync re-evaluation; the async caller will trampoline
-                from .evaluator import _eval as sync_eval, _trampoline
+                from .ref.sx_ref import eval_expr as sync_eval, trampoline as _trampoline
                 return _trampoline(sync_eval(body, env))
             finally:
                 _ASYNC_RESET_RESUME.pop()
diff --git a/shared/sx/evaluator.py b/shared/sx/evaluator.py
deleted file mode 100644
index 4e703528..00000000
--- a/shared/sx/evaluator.py
+++ /dev/null
@@ -1,94 +0,0 @@
-"""
-S-expression evaluator — thin shim over bootstrapped sx_ref.py.
-
-All evaluation logic lives in the spec (shared/sx/ref/eval.sx) and is
-bootstrapped to Python (shared/sx/ref/sx_ref.py).  This module re-exports
-the public API and internal helpers under their historical names so that
-existing callers don't need updating.
-
-Imports are lazy (inside functions/properties) to avoid circular imports
-during bootstrapping: bootstrap_py.py → parser → __init__ → evaluator → sx_ref.
-"""
-
-from __future__ import annotations
-
-
-def _ref():
-    """Lazy import of the bootstrapped evaluator."""
-    from .ref import sx_ref
-    return sx_ref
-
-
-# ---------------------------------------------------------------------------
-# Public API — these are the most used, so we make them importable directly
-# ---------------------------------------------------------------------------
-
-class EvalError(Exception):
-    """Error during expression evaluation.
-
-    Delegates to the bootstrapped EvalError at runtime but is defined here
-    so imports don't fail during bootstrapping.
-    """
-    pass
-
-
-def evaluate(expr, env=None):
-    return _ref().evaluate(expr, env)
-
-
-def make_env(**kwargs):
-    return _ref().make_env(**kwargs)
-
-
-# ---------------------------------------------------------------------------
-# Internal helpers — used by html.py, async_eval.py, handlers.py, etc.
-# ---------------------------------------------------------------------------
-
-def _eval(expr, env):
-    return _ref().eval_expr(expr, env)
-
-
-def _trampoline(val):
-    return _ref().trampoline(val)
-
-
-def _call_lambda(fn, args, caller_env):
-    return _ref().call_lambda(fn, args, caller_env)
-
-
-def _call_component(comp, raw_args, env):
-    return _ref().call_component(comp, raw_args, env)
-
-
-def _expand_macro(macro, raw_args, env):
-    return _ref().expand_macro(macro, raw_args, env)
-
-
-# ---------------------------------------------------------------------------
-# Special-form wrappers: callers pass (expr, env) with expr[0] = head symbol.
-# sx_ref.py special forms take (args, env) where args = expr[1:].
-# ---------------------------------------------------------------------------
-
-def _sf_defcomp(expr, env):
-    return _ref().sf_defcomp(expr[1:], env)
-
-def _sf_defisland(expr, env):
-    return _ref().sf_defisland(expr[1:], env)
-
-def _sf_defstyle(expr, env):
-    return _ref().sf_defstyle(expr[1:], env)
-
-def _sf_defmacro(expr, env):
-    return _ref().sf_defmacro(expr[1:], env)
-
-def _sf_defhandler(expr, env):
-    return _ref().sf_defhandler(expr[1:], env)
-
-def _sf_defpage(expr, env):
-    return _ref().sf_defpage(expr[1:], env)
-
-def _sf_defquery(expr, env):
-    return _ref().sf_defquery(expr[1:], env)
-
-def _sf_defaction(expr, env):
-    return _ref().sf_defaction(expr[1:], env)
diff --git a/shared/sx/handlers.py b/shared/sx/handlers.py
index 0aabd8a8..1a775d43 100644
--- a/shared/sx/handlers.py
+++ b/shared/sx/handlers.py
@@ -70,10 +70,7 @@ def load_handler_file(filepath: str, service_name: str) -> list[HandlerDef]:
     """Parse an .sx file, evaluate it, and register any HandlerDef values."""
     from .parser import parse_all
     import os
-    if os.environ.get("SX_USE_REF") == "1":
-        from .ref.sx_ref import eval_expr as _raw_eval, trampoline as _trampoline
-    else:
-        from .evaluator import _eval as _raw_eval, _trampoline
+    from .ref.sx_ref import eval_expr as _raw_eval, trampoline as _trampoline
     _eval = lambda expr, env: _trampoline(_raw_eval(expr, env))
     from .jinja_bridge import get_component_env
 
diff --git a/shared/sx/html.py b/shared/sx/html.py
index 2341bd98..f7fc9d50 100644
--- a/shared/sx/html.py
+++ b/shared/sx/html.py
@@ -28,7 +28,7 @@ import contextvars
 from typing import Any
 
 from .types import Component, Island, Keyword, Lambda, Macro, NIL, Symbol
-from .evaluator import _eval as _raw_eval, _call_component as _raw_call_component, _expand_macro, _trampoline
+from .ref.sx_ref import eval_expr as _raw_eval, call_component as _raw_call_component, expand_macro as _expand_macro, trampoline as _trampoline
 
 def _eval(expr, env):
     """Evaluate and unwrap thunks — all html.py _eval calls are non-tail."""
diff --git a/shared/sx/jinja_bridge.py b/shared/sx/jinja_bridge.py
index 9da4a6c4..167eac57 100644
--- a/shared/sx/jinja_bridge.py
+++ b/shared/sx/jinja_bridge.py
@@ -229,10 +229,7 @@ def register_components(sx_source: str) -> None:
                   (div :class "..." (div :class "..." title)))))
         ''')
     """
-    if _os.environ.get("SX_USE_REF") == "1":
-        from .ref.sx_ref import eval_expr as _raw_eval, trampoline as _trampoline
-    else:
-        from .evaluator import _eval as _raw_eval, _trampoline
+    from .ref.sx_ref import eval_expr as _raw_eval, trampoline as _trampoline
     _eval = lambda expr, env: _trampoline(_raw_eval(expr, env))
     from .parser import parse_all
     from .css_registry import scan_classes_from_sx
diff --git a/shared/sx/pages.py b/shared/sx/pages.py
index f0df5ce0..51dc76de 100644
--- a/shared/sx/pages.py
+++ b/shared/sx/pages.py
@@ -127,7 +127,7 @@ def get_page_helpers(service: str) -> dict[str, Any]:
 def load_page_file(filepath: str, service_name: str) -> list[PageDef]:
     """Parse an .sx file, evaluate it, and register any PageDef values."""
     from .parser import parse_all
-    from .evaluator import _eval as _raw_eval, _trampoline
+    from .ref.sx_ref import eval_expr as _raw_eval, trampoline as _trampoline
     _eval = lambda expr, env: _trampoline(_raw_eval(expr, env))
     from .jinja_bridge import get_component_env
 
diff --git a/shared/sx/parser.py b/shared/sx/parser.py
index c4ac622c..f4092936 100644
--- a/shared/sx/parser.py
+++ b/shared/sx/parser.py
@@ -41,7 +41,7 @@ def _resolve_sx_reader_macro(name: str):
     """
     try:
         from .jinja_bridge import get_component_env
-        from .evaluator import _trampoline, _call_lambda
+        from .ref.sx_ref import trampoline as _trampoline, call_lambda as _call_lambda
         from .types import Lambda
     except ImportError:
         return None
diff --git a/shared/sx/query_registry.py b/shared/sx/query_registry.py
index e6d63e35..3edda12e 100644
--- a/shared/sx/query_registry.py
+++ b/shared/sx/query_registry.py
@@ -78,7 +78,7 @@ def clear(service: str | None = None) -> None:
 def load_query_file(filepath: str, service_name: str) -> list[QueryDef]:
     """Parse an .sx file and register any defquery definitions."""
     from .parser import parse_all
-    from .evaluator import _eval as _raw_eval, _trampoline
+    from .ref.sx_ref import eval_expr as _raw_eval, trampoline as _trampoline
     _eval = lambda expr, env: _trampoline(_raw_eval(expr, env))
     from .jinja_bridge import get_component_env
 
@@ -103,7 +103,7 @@ def load_query_file(filepath: str, service_name: str) -> list[QueryDef]:
 def load_action_file(filepath: str, service_name: str) -> list[ActionDef]:
     """Parse an .sx file and register any defaction definitions."""
     from .parser import parse_all
-    from .evaluator import _eval as _raw_eval, _trampoline
+    from .ref.sx_ref import eval_expr as _raw_eval, trampoline as _trampoline
     _eval = lambda expr, env: _trampoline(_raw_eval(expr, env))
     from .jinja_bridge import get_component_env
 
diff --git a/shared/sx/ref/bootstrap_test.py b/shared/sx/ref/bootstrap_test.py
index 08eb64bc..0f1ef43c 100644
--- a/shared/sx/ref/bootstrap_test.py
+++ b/shared/sx/ref/bootstrap_test.py
@@ -143,7 +143,7 @@ def _emit_py(suites: list[dict], preamble: list) -> str:
     lines.append('')
     lines.append('import pytest')
     lines.append('from shared.sx.parser import parse_all')
-    lines.append('from shared.sx.evaluator import _eval, _trampoline')
+    lines.append('from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline')
     lines.append('')
     lines.append('')
     lines.append(f"_PREAMBLE = '''{preamble_escaped}'''")
diff --git a/shared/sx/ref/platform_py.py b/shared/sx/ref/platform_py.py
index c21be752..74fafaef 100644
--- a/shared/sx/ref/platform_py.py
+++ b/shared/sx/ref/platform_py.py
@@ -600,7 +600,7 @@ def sx_expr_source(x):
 
 
 try:
-    from shared.sx.evaluator import EvalError
+    from shared.sx.types import EvalError
 except ImportError:
     class EvalError(Exception):
         pass
diff --git a/shared/sx/ref/reader_z3.py b/shared/sx/ref/reader_z3.py
index f5c76239..8ab2297a 100644
--- a/shared/sx/ref/reader_z3.py
+++ b/shared/sx/ref/reader_z3.py
@@ -39,7 +39,7 @@ def _get_z3_env() -> dict[str, Any]:
         return _z3_env
 
     from shared.sx.parser import parse_all
-    from shared.sx.evaluator import make_env, _eval, _trampoline
+    from shared.sx.ref.sx_ref import make_env, eval_expr as _eval, trampoline as _trampoline
 
     env = make_env()
     z3_path = os.path.join(os.path.dirname(__file__), "z3.sx")
@@ -60,7 +60,7 @@ def z3_translate(expr: Any) -> str:
 
     Delegates to z3-translate defined in z3.sx.
     """
-    from shared.sx.evaluator import _trampoline, _call_lambda
+    from shared.sx.ref.sx_ref import trampoline as _trampoline, call_lambda as _call_lambda
 
     env = _get_z3_env()
     return _trampoline(_call_lambda(env["z3-translate"], [expr], env))
@@ -72,7 +72,7 @@ def z3_translate_file(source: str) -> str:
     Delegates to z3-translate-file defined in z3.sx.
     """
     from shared.sx.parser import parse_all
-    from shared.sx.evaluator import _trampoline, _call_lambda
+    from shared.sx.ref.sx_ref import trampoline as _trampoline, call_lambda as _call_lambda
 
     env = _get_z3_env()
     exprs = parse_all(source)
diff --git a/shared/sx/ref/run_js_sx.py b/shared/sx/ref/run_js_sx.py
index ebe478b6..9fd1e141 100644
--- a/shared/sx/ref/run_js_sx.py
+++ b/shared/sx/ref/run_js_sx.py
@@ -49,7 +49,7 @@ def load_js_sx() -> dict:
 
     exprs = parse_all(source)
 
-    from shared.sx.evaluator import evaluate, make_env
+    from shared.sx.ref.sx_ref import evaluate, make_env
 
     env = make_env()
     for expr in exprs:
@@ -74,7 +74,7 @@ def compile_ref_to_js(
         spec_modules: List of spec modules (deps, router, signals). None = auto.
     """
     from datetime import datetime, timezone
-    from shared.sx.evaluator import evaluate
+    from shared.sx.ref.sx_ref import evaluate
 
     ref_dir = _HERE
     env = load_js_sx()
diff --git a/shared/sx/ref/run_py_sx.py b/shared/sx/ref/run_py_sx.py
index ab170f5f..54927cf6 100644
--- a/shared/sx/ref/run_py_sx.py
+++ b/shared/sx/ref/run_py_sx.py
@@ -38,7 +38,7 @@ def load_py_sx(evaluator_env: dict) -> dict:
     exprs = parse_all(source)
 
     # Import the evaluator
-    from shared.sx.evaluator import evaluate, make_env
+    from shared.sx.ref.sx_ref import evaluate, make_env
 
     env = make_env()
     for expr in exprs:
@@ -60,7 +60,7 @@ def extract_defines(source: str) -> list[tuple[str, list]]:
 
 
 def main():
-    from shared.sx.evaluator import evaluate
+    from shared.sx.ref.sx_ref import evaluate
 
     # Load py.sx into evaluator
     env = load_py_sx({})
diff --git a/shared/sx/ref/sx_ref.py b/shared/sx/ref/sx_ref.py
index 427dced1..020daa3e 100644
--- a/shared/sx/ref/sx_ref.py
+++ b/shared/sx/ref/sx_ref.py
@@ -559,7 +559,7 @@ def sx_expr_source(x):
 
 
 try:
-    from shared.sx.evaluator import EvalError
+    from shared.sx.types import EvalError
 except ImportError:
     class EvalError(Exception):
         pass
diff --git a/shared/sx/resolver.py b/shared/sx/resolver.py
index 93622499..2b90c6fa 100644
--- a/shared/sx/resolver.py
+++ b/shared/sx/resolver.py
@@ -31,7 +31,7 @@ import asyncio
 from typing import Any
 
 from .types import Component, Keyword, Lambda, NIL, Symbol
-from .evaluator import _eval as _raw_eval, _trampoline
+from .ref.sx_ref import eval_expr as _raw_eval, trampoline as _trampoline
 
 def _eval(expr, env):
     """Evaluate and unwrap thunks — all resolver.py _eval calls are non-tail."""
diff --git a/shared/sx/tests/run.py b/shared/sx/tests/run.py
index c679d59a..abdc791a 100644
--- a/shared/sx/tests/run.py
+++ b/shared/sx/tests/run.py
@@ -20,7 +20,7 @@ _PROJECT = os.path.abspath(os.path.join(_HERE, "..", "..", ".."))
 sys.path.insert(0, _PROJECT)
 
 from shared.sx.parser import parse_all
-from shared.sx.evaluator import _eval, _trampoline, _call_lambda
+from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline, call_lambda as _call_lambda
 from shared.sx.types import Symbol, Keyword, Lambda, NIL, Component, Island
 
 # --- Test state ---
diff --git a/shared/sx/tests/test_bootstrapper.py b/shared/sx/tests/test_bootstrapper.py
index 4fb6416b..635943ea 100644
--- a/shared/sx/tests/test_bootstrapper.py
+++ b/shared/sx/tests/test_bootstrapper.py
@@ -21,7 +21,7 @@ class TestJsSxTranslation:
 
     def _translate(self, sx_source: str) -> str:
         """Translate a single SX expression to JS using js.sx."""
-        from shared.sx.evaluator import evaluate
+        from shared.sx.ref.sx_ref import evaluate
         env = load_js_sx()
         expr = parse(sx_source)
         env["_def_expr"] = expr
diff --git a/shared/sx/tests/test_deps.py b/shared/sx/tests/test_deps.py
index c5ca5262..a648a1ea 100644
--- a/shared/sx/tests/test_deps.py
+++ b/shared/sx/tests/test_deps.py
@@ -18,7 +18,7 @@ from shared.sx.deps import (
 
 def make_env(*sx_sources: str) -> dict:
     """Parse and evaluate component definitions into an env dict."""
-    from shared.sx.evaluator import _eval, _trampoline
+    from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline
     env: dict = {}
     for source in sx_sources:
         exprs = parse_all(source)
diff --git a/shared/sx/tests/test_io_detection.py b/shared/sx/tests/test_io_detection.py
index bac513ae..412c8996 100644
--- a/shared/sx/tests/test_io_detection.py
+++ b/shared/sx/tests/test_io_detection.py
@@ -23,7 +23,7 @@ from shared.sx.deps import (
 
 def make_env(*sx_sources: str) -> dict:
     """Parse and evaluate component definitions into an env dict."""
-    from shared.sx.evaluator import _eval, _trampoline
+    from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline
     env: dict = {}
     for source in sx_sources:
         exprs = parse_all(source)
diff --git a/shared/sx/tests/test_io_proxy.py b/shared/sx/tests/test_io_proxy.py
index 1516797f..8ccfd366 100644
--- a/shared/sx/tests/test_io_proxy.py
+++ b/shared/sx/tests/test_io_proxy.py
@@ -20,7 +20,7 @@ from shared.sx.deps import (
 
 def make_env(*sx_sources: str) -> dict:
     """Parse and evaluate component definitions into an env dict."""
-    from shared.sx.evaluator import _eval, _trampoline
+    from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline
     env: dict = {}
     for source in sx_sources:
         exprs = parse_all(source)
@@ -282,7 +282,7 @@ class TestIoRoutingLogic:
     """
 
     def _eval(self, src, env):
-        from shared.sx.evaluator import _eval, _trampoline
+        from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline
         result = None
         for expr in parse_all(src):
             result = _trampoline(_eval(expr, env))
diff --git a/shared/sx/tests/test_page_data.py b/shared/sx/tests/test_page_data.py
index 7cd22800..5789814d 100644
--- a/shared/sx/tests/test_page_data.py
+++ b/shared/sx/tests/test_page_data.py
@@ -156,7 +156,7 @@ class TestDataPageDeps:
     def test_deps_computed_for_data_page(self):
         from shared.sx.deps import components_needed
         from shared.sx.parser import parse_all as pa
-        from shared.sx.evaluator import _eval, _trampoline
+        from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline
 
         # Define a component
         env = {}
@@ -172,7 +172,7 @@ class TestDataPageDeps:
     def test_deps_transitive_for_data_page(self):
         from shared.sx.deps import components_needed
         from shared.sx.parser import parse_all as pa
-        from shared.sx.evaluator import _eval, _trampoline
+        from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline
 
         env = {}
         source = """
@@ -205,7 +205,7 @@ class TestDataPipelineSimulation:
 
     def test_full_pipeline(self):
         from shared.sx.parser import parse_all as pa
-        from shared.sx.evaluator import _eval, _trampoline
+        from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline
 
         # 1. Define a component that uses only pure primitives
         env = {}
@@ -236,7 +236,7 @@ class TestDataPipelineSimulation:
 
     def test_pipeline_with_list_data(self):
         from shared.sx.parser import parse_all as pa
-        from shared.sx.evaluator import _eval, _trampoline
+        from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline
 
         env = {}
         for expr in pa('''
@@ -262,7 +262,7 @@ class TestDataPipelineSimulation:
     def test_pipeline_data_isolation(self):
         """Different data for the same content produces different results."""
         from shared.sx.parser import parse_all as pa
-        from shared.sx.evaluator import _eval, _trampoline
+        from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline
 
         env = {}
         for expr in pa('(defcomp ~page (&key title count) (str title ": " count))'):
@@ -298,7 +298,7 @@ class TestDataCache:
     def _make_env(self, current_time_ms=1000):
         """Create an env with cache functions and a controllable now-ms."""
         from shared.sx.parser import parse_all as pa
-        from shared.sx.evaluator import _eval, _trampoline
+        from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline
 
         env = {}
         # Mock now-ms as a callable that returns current_time_ms
@@ -344,7 +344,7 @@ class TestDataCache:
 
     def _eval(self, src, env):
         from shared.sx.parser import parse_all as pa
-        from shared.sx.evaluator import _eval, _trampoline
+        from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline
         result = None
         for expr in pa(src):
             result = _trampoline(_eval(expr, env))
diff --git a/shared/sx/tests/test_parity.py b/shared/sx/tests/test_parity.py
index db809b02..0f079f51 100644
--- a/shared/sx/tests/test_parity.py
+++ b/shared/sx/tests/test_parity.py
@@ -18,7 +18,7 @@ from shared.sx.types import Symbol, Keyword, Lambda, Component, Macro, NIL
 
 def hw_eval(text, env=None):
     """Evaluate via hand-written evaluator.py."""
-    from shared.sx.evaluator import evaluate as _evaluate, EvalError
+    from shared.sx.ref.sx_ref import evaluate as _evaluate
     if env is None:
         env = {}
     return _evaluate(parse(text), env)
@@ -50,7 +50,7 @@ def ref_render(text, env=None):
 
 def hw_eval_multi(text, env=None):
     """Evaluate multiple expressions (e.g. defines then call)."""
-    from shared.sx.evaluator import evaluate as _evaluate
+    from shared.sx.ref.sx_ref import evaluate as _evaluate
     if env is None:
         env = {}
     result = None
@@ -736,7 +736,7 @@ class TestParityDeps:
 
 class TestParityErrors:
     def test_undefined_symbol(self):
-        from shared.sx.evaluator import EvalError as HwError
+        from shared.sx.types import EvalError as HwError
         from shared.sx.ref.sx_ref import EvalError as RefError
         with pytest.raises(HwError):
             hw_eval("undefined_var")
diff --git a/shared/sx/tests/test_sx_js.py b/shared/sx/tests/test_sx_js.py
index 135adaec..43b59aae 100644
--- a/shared/sx/tests/test_sx_js.py
+++ b/shared/sx/tests/test_sx_js.py
@@ -12,7 +12,7 @@ import pytest
 
 from shared.sx.parser import parse, parse_all
 from shared.sx.html import render as py_render
-from shared.sx.evaluator import evaluate
+from shared.sx.ref.sx_ref import evaluate
 
 SX_JS = Path(__file__).resolve().parents[2] / "static" / "scripts" / "sx.js"
 SX_TEST_JS = Path(__file__).resolve().parents[2] / "static" / "scripts" / "sx-test.js"
diff --git a/shared/sx/tests/test_sx_spec.py b/shared/sx/tests/test_sx_spec.py
index db885cce..51592761 100644
--- a/shared/sx/tests/test_sx_spec.py
+++ b/shared/sx/tests/test_sx_spec.py
@@ -7,7 +7,7 @@ from __future__ import annotations
 
 import pytest
 from shared.sx.parser import parse_all
-from shared.sx.evaluator import _eval, _trampoline
+from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline
 
 
 _PREAMBLE = '''(define assert-equal (fn (expected actual) (assert (equal? expected actual) (str "Expected " (str expected) " but got " (str actual)))))
diff --git a/shared/sx/types.py b/shared/sx/types.py
index 97f0e2fc..4ade10f4 100644
--- a/shared/sx/types.py
+++ b/shared/sx/types.py
@@ -375,6 +375,15 @@ class _ShiftSignal(BaseException):
         self.env = env
 
 
+# ---------------------------------------------------------------------------
+# EvalError
+# ---------------------------------------------------------------------------
+
+class EvalError(Exception):
+    """Error during expression evaluation."""
+    pass
+
+
 # ---------------------------------------------------------------------------
 # Type alias
 # ---------------------------------------------------------------------------
diff --git a/sx/sxc/pages/helpers.py b/sx/sxc/pages/helpers.py
index 102147d5..f8c6deea 100644
--- a/sx/sxc/pages/helpers.py
+++ b/sx/sxc/pages/helpers.py
@@ -314,7 +314,7 @@ def _self_hosting_data(ref_dir: str) -> dict:
     import os
     from shared.sx.parser import parse_all
     from shared.sx.types import Symbol
-    from shared.sx.evaluator import evaluate, make_env
+    from shared.sx.ref.sx_ref import evaluate, make_env
     from shared.sx.ref.bootstrap_py import extract_defines, compile_ref_to_py, PyEmitter
 
     try:
@@ -387,7 +387,7 @@ def _js_self_hosting_data(ref_dir: str) -> dict:
     """Run js.sx live: load into evaluator, translate all spec defines."""
     import os
     from shared.sx.types import Symbol
-    from shared.sx.evaluator import evaluate
+    from shared.sx.ref.sx_ref import evaluate
     from shared.sx.ref.run_js_sx import load_js_sx
     from shared.sx.ref.platform_js import extract_defines
 
@@ -661,7 +661,7 @@ def _run_spec_tests() -> dict:
     import os
     import time
     from shared.sx.parser import parse_all
-    from shared.sx.evaluator import _eval, _trampoline
+    from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline
 
     ref_dir = os.path.join(os.path.dirname(__file__), "..", "..", "shared", "sx", "ref")
     if not os.path.isdir(ref_dir):
@@ -735,7 +735,7 @@ def _run_modular_tests(spec_name: str) -> dict:
     import os
     import time
     from shared.sx.parser import parse_all
-    from shared.sx.evaluator import _eval, _trampoline
+    from shared.sx.ref.sx_ref import eval_expr as _eval, trampoline as _trampoline
     from shared.sx.types import Symbol, Keyword, Lambda, NIL
 
     ref_dir = os.path.join(os.path.dirname(__file__), "..", "..", "shared", "sx", "ref")
@@ -817,7 +817,7 @@ def _run_modular_tests(spec_name: str) -> dict:
 
     def _call_sx(fn, args, caller_env):
         if isinstance(fn, Lambda):
-            from shared.sx.evaluator import _call_lambda
+            from shared.sx.ref.sx_ref import call_lambda as _call_lambda
             return _trampoline(_call_lambda(fn, list(args), caller_env))
         return fn(*args)
 
@@ -1165,9 +1165,9 @@ def _prove_data() -> dict:
     """
     import time
     from shared.sx.parser import parse_all
-    from shared.sx.evaluator import evaluate
+    from shared.sx.ref.sx_ref import evaluate
     from shared.sx.primitives import all_primitives
-    from shared.sx.evaluator import _trampoline, _call_lambda
+    from shared.sx.ref.sx_ref import trampoline as _trampoline, call_lambda as _call_lambda
 
     env = all_primitives()