aeson / release-notes.markdown

Diff from to


 * Instances of `ToJSON` and `FromJSON` for tuples are between 45% and
   70% faster than in 0.3.
+## Evaluation control
+This version of aeson makes explicit the decoupling between
+*identifying* an element of a JSON document and *converting* it to
+Haskell.  See the
+documentation for details.
+The normal aeson `decode` function performs identification strictly,
+but defers conversion until needed.  This can result in improved
+performance (e.g. if the results of some conversions are never
+needed), but at a cost in increased memory consumption.
+The new `decode'` function performs identification and conversion
+immediately.  This incurs an up-front cost in CPU cycles, but reduces
+reduce memory consumption.