Modularized the tool.

rstat_tool/sentiment_analyzer.py

@@ -0,0 +1,19 @@
+# sentiment_analyzer.py
+
+from nltk.sentiment.vader import SentimentIntensityAnalyzer
+
+# Initialize the VADER sentiment intensity analyzer
+# We only need to create one instance of this.
+_analyzer = SentimentIntensityAnalyzer()
+
+def get_sentiment_score(text):
+    """
+    Analyzes a piece of text and returns its sentiment score.
+    
+    The 'compound' score is a single metric that summarizes the sentiment.
+    It ranges from -1 (most negative) to +1 (most positive).
+    """
+    # The polarity_scores() method returns a dictionary with 'neg', 'neu', 'pos', and 'compound' scores.
+    # We are most interested in the 'compound' score.
+    scores = _analyzer.polarity_scores(text)
+    return scores['compound']