Fixed issue 63

1 files changed, 19 insertions, 11 deletions

diff --git a/ply/yacc.py b/ply/yacc.py
index f18e3eb..e0b4faf 100644
--- a/ply/yacc.py
+++ b/ply/yacc.py
@@ -2692,7 +2692,11 @@ class LRGeneratedTable(LRTable):
     # This function writes the LR parsing tables to a file
     # -----------------------------------------------------------------------------
 
-    def write_table(self, basemodulename, outputdir='', signature=''):
+    def write_table(self, tabmodule, outputdir='', signature=''):
+        if isinstance(tabmodule, types.ModuleType):
+            raise IOError("Won't overwrite existing tabmodule")
+
+        basemodulename = tabmodule.split('.')[-1]
         filename = os.path.join(outputdir, basemodulename) + '.py'
         try:
             f = open(filename, 'w')
@@ -3204,22 +3208,26 @@ def yacc(method='LALR', debug=yaccdebug, module=None, tabmodule=tab_module, star
         # is determined according to the following rules:
         #     - If tabmodule specifies a package, files go into that package directory
         #     - Otherwise, files go in the same directory as the specifying module
-        if '.' not in tabmodule:
-            srcfile = pdict['__file__']
+        if isinstance(tabmodule, types.ModuleType):
+            srcfile = tabmodule.__file__
         else:
-            parts = tabmodule.split('.')
-            pkgname = '.'.join(parts[:-1])
-            exec('import %s' % pkgname)
-            srcfile = getattr(sys.modules[pkgname], '__file__', '')
+            if '.' not in tabmodule:
+                srcfile = pdict['__file__']
+            else:
+                parts = tabmodule.split('.')
+                pkgname = '.'.join(parts[:-1])
+                exec('import %s' % pkgname)
+                srcfile = getattr(sys.modules[pkgname], '__file__', '')
         outputdir = os.path.dirname(srcfile)
 
     # Determine if the module is package of a package or not.
     # If so, fix the tabmodule setting so that tables load correctly
     pkg = pdict.get('__package__')
-    if pkg and '.' not in tabmodule:
-        tabmodule = pkg + '.' + tabmodule
+    if pkg and isinstance(tabmodule, str):
+        if '.' not in tabmodule:
+            tabmodule = pkg + '.' + tabmodule
+
 
-    basetabmodule = tabmodule.split('.')[-1]
 
     # Set start symbol if it's specified directly using an argument
     if start is not None:
@@ -3432,7 +3440,7 @@ def yacc(method='LALR', debug=yaccdebug, module=None, tabmodule=tab_module, star
     # Write the table file if requested
     if write_tables:
         try:
-            lr.write_table(basetabmodule, outputdir, signature)
+            lr.write_table(tabmodule, outputdir, signature)
         except IOError as e:
             errorlog.warning("Couldn't create %r. %s" % (tabmodule, e))