Read 12,5 as 12.5 when normalising amounts

src/loraft/task.py

@@ -97,7 +97,10 @@ def _norm_amount(v) -> float | None:
     if "," in s and "." in s:
         s = s.replace(",", "") if s.rfind(".") > s.rfind(",") else s.replace(".", "").replace(",", ".")
     elif "," in s:
-        s = s.replace(",", ".") if len(s.split(",")[-1]) == 2 else s.replace(",", "")
+        # Only commas that split off groups of exactly three digits are
+        # thousands separators ("1,204", "12,000,000"). "12,5" and "12,50" are
+        # decimal commas.
+        s = s.replace(",", "") if re.fullmatch(r"-?\d{1,3}(,\d{3})+", s) else s.replace(",", ".")
     try:
         return round(float(s), 2)
     except ValueError:

tests/test_task.py

@@ -101,3 +101,11 @@ def test_generator_produces_null_examples():
     rows = data.generate(n=200)
     n_null = sum(1 for r in rows if all(r["gold"][f] is None for f in config.FIELDS))
     assert n_null > 0, "without all-null training rows the model never learns to abstain"
+
+
+@pytest.mark.parametrize("raw,want", [
+    ("12,5", 12.5), ("12,50", 12.5), ("1,204", 1204.0), ("12,000,000", 12000000.0),
+    ("1.204,55", 1204.55), ("1,204.55", 1204.55), ("€12,5", 12.5), ("-3,75", -3.75),
+])
+def test_norm_amount_comma(raw, want):
+    assert task._norm_amount(raw) == want

verify/score.c

@@ -506,10 +506,23 @@ static Norm norm_amount(const JVal *v)
                 }
             }
         } else if (last_comma) {
-            size_t tail = k - (size_t)(last_comma - buf) - 1;
+            /* thousands only for -?d{1,3}(,ddd)+ ; any other comma is a decimal
+               comma, so "12,5" is 12.5 and "1,204" is 1204 */
+            int thousands = 1;
+            size_t lead = 0, p0 = buf[0] == '-' ? 1 : 0;
+            for (j = p0; j < k && buf[j] != ','; j++)
+                lead++;
+            if (lead < 1 || lead > 3)
+                thousands = 0;
+            for (; thousands && j < k; j += 4) {
+                if (buf[j] != ',' || j + 3 >= k ||
+                    !isdigit((unsigned char)buf[j + 1]) || !isdigit((unsigned char)buf[j + 2]) ||
+                    !isdigit((unsigned char)buf[j + 3]))
+                    thousands = 0;
+            }
             for (j = 0; j < k; j++) {
                 if (buf[j] == ',') {
-                    if (tail == 2)
+                    if (!thousands)
                         tmp[w++] = '.';
                 } else {
                     tmp[w++] = buf[j];