You know that thing they say about how ''.join(slist) is faster than s1 += s? It's really true. This one change removed 90% of the templite time, and 59% of the html report generation time.

1 files changed, 2 insertions, 2 deletions

diff --git a/coverage/templite.py b/coverage/templite.py
index d3c673c6..66f38a9c 100644
--- a/coverage/templite.py
+++ b/coverage/templite.py
@@ -101,14 +101,14 @@ class Templite(object):
         # Run it through an engine, and return the result.
         engine = _TempliteEngine(ctx)
         engine.execute(self.ops)
-        return engine.result
+        return "".join(engine.result)
 
 
 class _TempliteEngine(object):
     """Executes Templite objects to produce strings."""
     def __init__(self, context):
         self.context = context
-        self.result = ""
+        self.result = []
 
     def execute(self, ops):
         """Execute `ops` in the engine.