c_client.py: Extract get_expr_field_names()

Signed-off-by: Povilas Kanapickas <povilas@radix.lt>

src/c_client.py

@@ -649,23 +649,22 @@ def _c_helper_resolve_field_names (prefix):
 
     return all_fields
 
-def get_expr_fields(self):
-    """
-    get the Fields referenced by switch or list expression
-    """
+
 def get_expr_field_names(expr):
+    """
+    returns a list of field names referenced in an expression
+    """
     if expr.op is None or expr.op == 'calculate_len':
         if expr.lenfield_name is not None:
             return [expr.lenfield_name]
-            else:
         # constant value expr
         return []
-        else:
+
     if expr.op == '~':
         return get_expr_field_names(expr.rhs)
-            elif expr.op == 'popcount':
+    if expr.op == 'popcount':
         return get_expr_field_names(expr.rhs)
-            elif expr.op == 'sumof':
+    if expr.op == 'sumof':
         # sumof expr references another list,
         # we need that list's length field here
         field = None
@@ -677,11 +676,15 @@ def get_expr_fields(self):
             raise Exception("list field '%s' referenced by sumof not found" % expr.lenfield_name)
         # referenced list + its length field
         return [expr.lenfield_name] + get_expr_field_names(field.type.expr)
-            elif expr.op == 'enumref':
+    if expr.op == 'enumref':
         return []
-            else:
     return get_expr_field_names(expr.lhs) + get_expr_field_names(expr.rhs)
-    # get_expr_field_names()
+
+
+def get_expr_fields(self):
+    """
+    get the Fields referenced by switch or list expression
+    """
 
     # resolve the field names with the parent structure(s)
     unresolved_fields_names = get_expr_field_names(self.expr)