gsm_symbolic generator changes

reasoning_gym/utils.py

@@ -1,5 +1,8 @@
+import math
 import re
-from typing import Optional
+from decimal import Decimal, InvalidOperation
+from fractions import Fraction
+from typing import Any, Optional, Union
 
 # DeepSeek Zero system prompt
 SYSTEM_PROMPTS = {
@@ -22,3 +25,52 @@ def extract_answer(completion: str, tag_name: str = "answer") -> Optional[str]:
     if not matches:
         return None
     return matches[-1].group(1)
+
+
+def format_number(num: Union[int, float], max_decimals: int = 2) -> str:
+    """Convert a number to string representation with controlled decimal places.
+
+    Args:
+        num: Number to format
+        max_decimals: Maximum allowed decimal places
+
+    Returns:
+        String representation of the number
+
+    Raises:
+        ValueError: If number requires more decimal places than allowed
+    """
+    if isinstance(num, int) or num.is_integer():
+        return str(int(num))
+
+    # Convert to Decimal for exact decimal arithmetic
+    d = Decimal(str(num))
+
+    # Find required decimals by removing trailing zeros
+    str_val = f"{d:f}"
+    str_val = str_val.rstrip("0").rstrip(".")
+    if "." in str_val:
+        required_decimals = len(str_val.split(".")[1])
+        if required_decimals > max_decimals:
+            raise ValueError(f"Number {num} requires {required_decimals} decimals but only {max_decimals} allowed")
+
+    # Format with required decimals
+    result = f"{num:.{max_decimals}f}".rstrip("0").rstrip(".")
+
+    # Verify result parses back to original value
+    try:
+        parsed = float(result)
+        if not math.isclose(parsed, num, rel_tol=1e-9):
+            raise ValueError(f"String representation {result} does not match original value {num}")
+    except (ValueError, InvalidOperation) as e:
+        raise ValueError(f"Failed to verify string representation: {e}")
+
+    return result
+
+
+def is_integer(obj: Any) -> bool:
+    if isinstance(obj, (int, float)):
+        return isinstance(obj, int) or obj.is_integer()
+    elif isinstance(obj, Fraction):
+        return obj.denominator == 1
+    return False