Hence PyPy people rewriting CPython's C extensions in Python to make them fast. For example, rewriting JSON encoding from C to Python resulted in a decent speed

Hence PyPy people rewriting CPython's C extensions in Python to make them fast. For example, rewriting JSON encoding from C to Python resulted in a decent speedup. http://morepypy.blogspot.com/2011/10/speeding-up-json-encoding-in-pypy.html http://morepypy.blogspot.com/2011/10/speeding-up-json-encodi...