Fix things so that JSON output does not keep all objects in memory at once.

1 files changed, 13 insertions, 1 deletions

diff --git a/summain b/summain
index cf35a41..579c6d9 100755
--- a/summain
+++ b/summain
@@ -70,10 +70,22 @@ class CSV(OutputFormat):
         self.writer.writerow(values)
 
 
+class GeneratorList(list):
+
+    def __init__(self, gen):
+        self.gen = gen
+        
+    def __len__(self):
+        return 1
+
+    def __iter__(self):
+        return iter(self.gen)
+
+
 class Json(OutputFormat):
 
     def write(self):
-        json.dump(list(self.dictify(name, o) for name, o in self.objects), 
+        json.dump(GeneratorList(self.dictify(name, o) for name, o in self.objects), 
                   self.output, sort_keys=True, indent=1)
         self.output.write('\n')