feat: emit SCJUMP decision table (json+md, registry-named) (Task 3)

build/scjump-decisions.* are generated (build/ gitignored).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tools/scjump_decode.py

@@ -142,6 +142,74 @@ def decode(scr):
     return decisions
 
 
+def load_names() -> dict:
+    """addr:int -> curated registry name (from build/globals.json), or {} if absent."""
+    try:
+        data = json.loads((paths.BUILD / "globals.json").read_text(encoding="utf-8"))
+    except Exception:
+        return {}
+    out = {}
+    for addr_s, e in data.get("globals", {}).items():
+        if e.get("name"):
+            out[int(addr_s, 16)] = e["name"]
+    return out
+
+
+def render_guard(g, names) -> str:
+    if "opaque" in g:  return g["opaque"]
+    if "and" in g:     return "(" + " AND ".join(render_guard(x, names) for x in g["and"]) + ")"
+    if "or" in g:      return "(" + " OR ".join(render_guard(x, names) for x in g["or"]) + ")"
+    lbl = names.get(g["global"], f"0x{g['global']:x}")
+    return f"{lbl}{g['op']}{g['value']}"
+
+
+def emit_json(decs, names) -> str:
+    def jguard(g):
+        if "opaque" in g or "and" in g or "or" in g: return g
+        return {"global": f"0x{g['global']:x}", "name": names.get(g["global"]), "op": g["op"], "value": g["value"]}
+    out_decs = [{"site_offset": f"0x{d['site_offset']:x}", "chapter": d["chapter"],
+                 "decision": d["decision"], "guards": [jguard(g) for g in d["guards"]]} for d in decs]
+    by_chapter = collections.defaultdict(list)
+    for d in out_decs:
+        by_chapter[d["chapter"]].append(d["decision"])
+    meta = {"note": "GENERATED by tools/scjump_decode.py — do not edit. Decision->scene is native (u00428010), not resolved here.",
+            "decision_sites": len({d["site_offset"] for d in decs}),
+            "distinct_decisions": len({d["decision"] for d in decs})}
+    return json.dumps({"meta": meta, "decisions": out_decs,
+                       "by_chapter": {str(k): sorted(set(v)) for k, v in sorted(by_chapter.items(), key=lambda kv: (kv[0] is None, kv[0]))}},
+                      ensure_ascii=False, indent=2) + "\n"
+
+
+def emit_md(decs, names) -> str:
+    L = ["<!-- GENERATED by tools/scjump_decode.py — do not edit -->",
+         "# SCJUMP progression decisions (generated)", "",
+         f"{len({d['site_offset'] for d in decs})} decision sites. Each rule: guards (all true along the "
+         "path) -> decision value written to `0x62ccf`. Decision->scene is native (`u00428010`), see "
+         "`docs/scjump-progression.md`.", ""]
+    by_ch = collections.defaultdict(list)
+    for d in decs:
+        by_ch[d["chapter"]].append(d)
+    for ch in sorted(by_ch, key=lambda c: (c is None, c)):
+        L += [f"## chapter {ch}", ""]
+        for d in sorted(by_ch[ch], key=lambda d: d["site_offset"]):
+            guards = " AND ".join(render_guard(g, names) for g in d["guards"]) or "(unconditional)"
+            L.append(f"- `0x{d['site_offset']:x}`: {guards} → **decision {d['decision']}**")
+        L.append("")
+    return "\n".join(L) + "\n"
+
+
+def build(scr=None) -> int:
+    scr = scr or load_scjump()
+    decs = decode(scr)
+    names = load_names()
+    paths.BUILD.mkdir(parents=True, exist_ok=True)
+    (paths.BUILD / "scjump-decisions.json").write_text(emit_json(decs, names), encoding="utf-8")
+    (paths.BUILD / "scjump-decisions.md").write_text(emit_md(decs, names), encoding="utf-8")
+    print(f"decode: {len({d['site_offset'] for d in decs})} decision sites, "
+          f"{len({d['decision'] for d in decs})} distinct decisions -> build/scjump-decisions.{{json,md}}")
+    return 0
+
+
 def main(argv=None):
     ap = argparse.ArgumentParser()
     ap.add_argument("--verify", action="store_true")   # implemented in Task 4

tools/test_scjump.py

@@ -29,8 +29,20 @@ def test_decode_anchor_and_count():
     check(has_chapter, "anchor guarded by chapter_mode==1")
     check(has_flag, "anchor guarded by 0x6d3!=1")
 
+def test_emit_json_shape():
+    scr = S.load_scjump()
+    decs = S.decode(scr)
+    names = S.load_names()
+    obj = json.loads(S.emit_json(decs, names))
+    check(obj["meta"]["decision_sites"] == 1755, "json meta reports 1755 sites")
+    check(all(set(("site_offset", "chapter", "decision", "guards")) <= set(d) for d in obj["decisions"]), "each decision has required keys")
+    # rendering uses registry names when present
+    check(S.render_guard({"global": 0x3234, "op": "==", "value": 7}, {0x3234: "chapter_mode"}) == "chapter_mode==7",
+          "render_guard uses registry name")
+
 if __name__ == "__main__":
     test_cfg_acyclic_and_dispatch()
     test_decode_anchor_and_count()
+    test_emit_json_shape()
     print(f"\n{len(FAILS)} failures")
     sys.exit(1 if FAILS else 0)