feat: Add word reversal task generator with configurable word count

reasoning_gym/algorithmic/__init__.py

@@ -7,5 +7,13 @@ Algorithmic tasks for training reasoning capabilities:
 """
 
 from .letter_counting import LetterCountingConfig, LetterCountingDataset, letter_counting_dataset
+from .word_reversal import WordReversalConfig, WordReversalDataset, word_reversal_dataset
 
-__all__ = ["LetterCountingConfig", "LetterCountingDataset", "letter_counting_dataset"]
+__all__ = [
+    "LetterCountingConfig", 
+    "LetterCountingDataset", 
+    "letter_counting_dataset",
+    "WordReversalConfig",
+    "WordReversalDataset",
+    "word_reversal_dataset"
+]

reasoning_gym/algorithmic/word_reversal.py

@@ -0,0 +1,86 @@
+"""Word reversal task generator"""
+from dataclasses import dataclass
+import re
+from random import Random
+from typing import List, Optional
+
+from reasoning_gym.data import read_data_file
+
+@dataclass
+class WordReversalConfig:
+    """Configuration for word reversal task generation"""
+    min_words: int = 3          # Minimum words in list
+    max_words: int = 8          # Maximum words in list
+    seed: Optional[int] = None
+    size: int = 500            # Virtual dataset size
+
+    def validate(self):
+        """Validate configuration parameters"""
+        assert self.min_words > 0, "min_words must be positive"
+        assert self.max_words >= self.min_words, "max_words must be >= min_words"
+
+
+class WordReversalDataset:
+    """Generates word reversal tasks from text spans"""
+
+    def __init__(self, config: WordReversalConfig):
+        self.config = config
+        self.config.validate()
+        self.seed = config.seed if config.seed is not None else Random().randint(0, 2**32)
+        
+        # Load and preprocess text
+        text = read_data_file("in_the_year_2889.txt")
+        # Extract words and clean them to contain only alphanumeric characters
+        self.words = [word for word in re.findall(r'\b\w+\b', text) if word.isalnum()]
+
+    def __len__(self) -> int:
+        return self.config.size
+
+    def __iter__(self):
+        self._current_idx = 0
+        return self
+
+    def __next__(self):
+        if self._current_idx >= self.config.size:
+            raise StopIteration
+        item = self[self._current_idx]
+        self._current_idx += 1
+        return item
+
+    def __getitem__(self, idx: int) -> dict:
+        """Generate a single word reversal task"""
+        rng = Random(self.seed + idx)
+        
+        # Select random words
+        num_words = rng.randint(self.config.min_words, self.config.max_words)
+        word_indices = rng.sample(range(len(self.words)), num_words)
+        words = [self.words[i] for i in word_indices]
+        
+        # Create question and answer
+        question = ", ".join(words)
+        answer = ", ".join(reversed(words))
+        
+        return {
+            "question": f"Reverse this list of words: {question}",
+            "answer": answer,
+            "metadata": {
+                "num_words": num_words,
+                "words": words
+            }
+        }
+
+
+def word_reversal_dataset(
+    min_words: int = 3,
+    max_words: int = 8,
+    seed: Optional[int] = None,
+    size: int = 500,
+) -> WordReversalDataset:
+    """Create a WordReversalDataset with the given configuration."""
+    config = WordReversalConfig(
+        min_words=min_words,
+        max_words=max_words,
+        seed=seed,
+        size=size,
+    )
+    return WordReversalDataset(config)