Phase 3: Move host files to hosts/python/ and hosts/javascript/

Python: bootstrap.py, platform.py, transpiler.sx, boundary_parser.py, tests/
JavaScript: bootstrap.py, cli.py, platform.py, transpiler.sx
Both bootstrappers verified — build from new locations, output to shared/.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hosts/javascript/bootstrap.py

@@ -16,13 +16,13 @@ import os
 import sys
 
 _HERE = os.path.dirname(os.path.abspath(__file__))
-_PROJECT = os.path.abspath(os.path.join(_HERE, "..", "..", ".."))
+_PROJECT = os.path.abspath(os.path.join(_HERE, "..", ".."))
 if _PROJECT not in sys.path:
     sys.path.insert(0, _PROJECT)
 
 from shared.sx.parser import parse_all
 from shared.sx.types import Symbol
-from shared.sx.ref.platform_js import (
+from hosts.javascript.platform import (
     extract_defines,
     ADAPTER_FILES, ADAPTER_DEPS, SPEC_MODULES, SPEC_MODULE_ORDER, EXTENSION_NAMES,
     PREAMBLE, PLATFORM_JS_PRE, PLATFORM_JS_POST,
@@ -44,7 +44,7 @@ def load_js_sx() -> dict:
     if _js_sx_env is not None:
         return _js_sx_env
 
-    js_sx_path = os.path.join(_HERE, "js.sx")
+    js_sx_path = os.path.join(_HERE, "transpiler.sx")
     with open(js_sx_path) as f:
         source = f.read()
 
@@ -77,8 +77,7 @@ def compile_ref_to_js(
     from datetime import datetime, timezone
     from shared.sx.ref.sx_ref import evaluate
 
-    ref_dir = _HERE
+    ref_dir = os.path.join(_PROJECT, "shared", "sx", "ref")
-    _PROJECT = os.path.abspath(os.path.join(_HERE, "..", "..", ".."))
     # Source directories: core spec, web framework, and legacy ref (for bootstrapper tools)
     _source_dirs = [
         os.path.join(_PROJECT, "spec"),      # Core spec

hosts/javascript/cli.py

@@ -20,8 +20,10 @@ if _PROJECT not in sys.path:
 
 # Re-export everything that consumers import from this module.
 # Canonical source is now run_js_sx.py (self-hosting via js.sx) and platform_js.py.
-from shared.sx.ref.run_js_sx import compile_ref_to_js, load_js_sx  # noqa: F401
+import sys, os
-from shared.sx.ref.platform_js import (  # noqa: F401
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "..")))
+from hosts.javascript.bootstrap import compile_ref_to_js, load_js_sx  # noqa: F401
+from hosts.javascript.platform import (  # noqa: F401
     extract_defines,
     ADAPTER_FILES, ADAPTER_DEPS, SPEC_MODULES, EXTENSION_NAMES,
     PREAMBLE, PLATFORM_JS_PRE, PLATFORM_JS_POST,
@@ -44,7 +46,7 @@ if __name__ == "__main__":
                     help="Comma-separated extensions (continuations). Default: none.")
     p.add_argument("--spec-modules",
                     help="Comma-separated spec modules (deps). Default: none.")
-    default_output = os.path.join(_HERE, "..", "..", "static", "scripts", "sx-browser.js")
+    default_output = os.path.join(_HERE, "..", "..", "shared", "static", "scripts", "sx-browser.js")
     p.add_argument("--output", "-o", default=default_output,
                     help="Output file (default: shared/static/scripts/sx-browser.js)")
     args = p.parse_args()

hosts/python/bootstrap.py

@@ -20,7 +20,7 @@ import sys
 
 # Add project root to path for imports
 _HERE = os.path.dirname(os.path.abspath(__file__))
-_PROJECT = os.path.abspath(os.path.join(_HERE, "..", "..", ".."))
+_PROJECT = os.path.abspath(os.path.join(_HERE, "..", ".."))
 sys.path.insert(0, _PROJECT)
 
 from shared.sx.parser import parse_all
@@ -1313,7 +1313,7 @@ try:
         EXTENSION_NAMES, EXTENSION_FORMS,
     )
 except ImportError:
-    from shared.sx.ref.platform_py import (
+    from hosts.python.platform import (
         PREAMBLE, PLATFORM_PY, PRIMITIVES_PY_PRE, PRIMITIVES_PY_POST,
         PRIMITIVES_PY_MODULES, _ALL_PY_MODULES,
         PLATFORM_PARSER_PY,
@@ -1439,8 +1439,8 @@ def compile_ref_to_py(
                     raise ValueError(f"Unknown module: {m!r}. Valid: {', '.join(PRIMITIVES_PY_MODULES)}")
                 prim_modules.append(m)
 
-    ref_dir = os.path.dirname(os.path.abspath(__file__))
+    ref_dir = os.path.join(os.path.abspath(os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", "..")), "shared", "sx", "ref")
-    _project = os.path.abspath(os.path.join(ref_dir, "..", "..", ".."))
+    _project = os.path.abspath(os.path.join(ref_dir, "..", ".."))
     _source_dirs = [
         os.path.join(_project, "spec"),
         os.path.join(_project, "web"),

shared/static/scripts/sx-browser.js

@@ -14,7 +14,7 @@
   // =========================================================================
 
   var NIL = Object.freeze({ _nil: true, toString: function() { return "nil"; } });
-  var SX_VERSION = "2026-03-15T02:11:58Z";
+  var SX_VERSION = "2026-03-15T02:18:33Z";
 
   function isNil(x) { return x === NIL || x === null || x === undefined; }
   function isSxTruthy(x) { return x !== false && !isNil(x); }