Fix two bugs in prolog.util.decompose

1 files changed, 4 insertions, 3 deletions

diff --git a/prolog/util.py b/prolog/util.py
index eb026fe..6091b17 100644
--- a/prolog/util.py
+++ b/prolog/util.py
@@ -40,16 +40,17 @@ def decompose(code):
     rule_start = 0
     for t in tokens:
         if t[0] == 'SEMI':
-            lines.append(line[:])
+            if line != []:
+                lines.append(line[:])
+                line = []
             lines.append([t])
-            line = []
             continue
         if not parens:
             if t[0] in ('PERIOD', 'FROM', 'COMMA', 'EOF'):
                 if line != []:
                     lines.append(line[:])
                     line = []
-                if t[0] in ('PERIOD', 'EOF'):
+                if t[0] in ('PERIOD', 'EOF') and rule_start < len(lines):
                     rules.append((rule_start, len(lines)))
                     rule_start = len(lines)
                 continue