fix(scoring): strip frac parens around post-#434 power atoms

pyproject.toml

@@ -18,7 +18,7 @@ dependencies = [
 ]
 
 [project.optional-dependencies]
-dev = ["pytest>=8.0", "ruff>=0.5", "mypy>=1.10"]
+dev = ["pytest>=8.0", "ruff>=0.5,<0.16", "mypy>=1.10"]
 
 [build-system]
 requires = ["hatchling"]

src/trinity/adapters/drop.py

@@ -130,9 +130,12 @@ def _maybe_unbox(segment: str) -> str:
     return boxed if boxed is not None else ""
 
 
-#: Surrounding punctuation stripped from a token, EXCLUDING the signs ``+``/``-`` — a
-#: leading sign is part of a number's value, not wrapping noise.
-_STRIP_EDGE = "".join(c for c in string.punctuation if c not in "+-")
+#: Surrounding punctuation stripped from a token, EXCLUDING the signs ``+``/``-`` and
+#: the decimal point ``.`` — a leading sign or decimal point is part of a number's
+#: value, not wrapping noise. A genuinely-trailing ``.`` (sentence period) is handled
+#: by the dedicated rstrip retry in :func:`_normalize_token`, which can tell it apart
+#: from a value-bearing leading point; a blanket edge-strip cannot.
+_STRIP_EDGE = "".join(c for c in string.punctuation if c not in "+-.")
 
 
 def _normalize_token(raw: str) -> str:
@@ -147,20 +150,27 @@ def _normalize_token(raw: str) -> str:
     dropped the ``-`` and left commas to break ``float()``) did not deliver.
 
     A token that is ALREADY a number is recognised before any punctuation is
-    stripped: the edge-strip set includes ``.``, so a leading-decimal token like
-    ``".5"`` would otherwise lose its point and normalize to ``"5.0"`` — equal to
-    a gold ``"5"`` (false positive) and unequal to the value-identical gold
-    ``"0.5"`` (false negative). The official DROP ``_remove_punc`` tests
-    ``_is_number`` first and leaves numbers untouched for exactly this reason."""
+    stripped: a leading-decimal token like ``".5"`` must not lose its point and
+    normalize to ``"5.0"`` — equal to a gold ``"5"`` (false positive) and unequal
+    to the value-identical gold ``"0.5"`` (false negative). The official DROP
+    ``_remove_punc`` tests ``_is_number`` first and leaves numbers untouched for
+    exactly this reason (issue #423). The float-first path alone only covers the
+    *bare* token: with ``.`` in the edge-strip set, wrapped forms like ``"$.5"``
+    and ``".5."`` still lost the leading point on the second-chance path. So the
+    edge strip excludes ``.`` entirely, and a genuinely-trailing period (``".5."``,
+    ``"16.."``) is retried with an explicit ``rstrip(".")`` — right-side dots are
+    sentence punctuation, left-side dots are value."""
     try:
         return str(float(raw.replace(",", "")))
     except ValueError:
         pass
     core = raw.strip(_STRIP_EDGE)
-    try:
-        return str(float(core.replace(",", "")))
-    except ValueError:
-        return _PUNCT.sub("", raw)
+    for cand in (core, core.rstrip(".")):
+        try:
+            return str(float(cand.replace(",", "")))
+        except ValueError:
+            continue
+    return _PUNCT.sub("", raw)
 
 
 def _split_internal_hyphens(token: str) -> list[str]:

src/trinity/orchestration/reward.py

@@ -847,8 +847,13 @@ def normalize_math_answer(ans: str | None) -> str:
     # standalone atomic operands adjacent to division — including a lone
     # ``sqrt(...)`` call produced from ``\sqrt{...}`` — without eating the
     # function-call parentheses themselves (``(sqrt(2))`` -> ``sqrt(2)``).
+    # Include #434's ``base^(...)`` spelling: the strip runs *after*
+    # ``_normalize_braced_exponents``, so ``x^{2}`` / ``2^{10}`` already look
+    # like ``x^(2)`` / ``2^(10)``. Without that branch, ``\frac{x^{2}}{2}``
+    # stays ``(x^(2))/2`` while the slash form is ``x^(2)/2`` (exact-match
+    # false negative; only sympy saves it).
     s = re.sub(
-        r"(^|/)\((pi|\d+|sqrt\([^()]*\)|[a-z](?:\^\{[^{}]*\}|\^[0-9a-z])?)\)(?=/|$)",
+        r"(^|/)\((pi|\d+|sqrt\([^()]*\)|(?:\d+|[a-z])(?:\^\([^()]*\)|\^\{[^{}]*\}|\^[0-9a-z])?)\)(?=/|$)",
         r"\1\2",
         s,
     )

tests/test_reward_nested_frac_unwrap.py

@@ -18,5 +18,9 @@ def test_plain_frac_still_matches():
 
 def test_frac_with_superscript_operand():
     # Braced superscript in the numerator is the same [^{}]+ failure mode.
+    # Exact normalize must agree — do not rely on the sympy fallback.
     assert "\\frac" not in normalize_math_answer(r"\frac{x^{2}}{2}")
+    assert normalize_math_answer(r"\frac{x^{2}}{2}") == normalize_math_answer(r"x^{2}/2")
     assert math_equal(r"\frac{x^{2}}{2}", r"x^{2}/2")
+    assert normalize_math_answer(r"\frac{2^{10}}{2}") == normalize_math_answer(r"2^{10}/2")
+    assert math_equal(r"\frac{2^{10}}{2}", r"2^{10}/2")