Python too slow?

Ed Jensen ejensen at
Fri Jan 11 17:23:46 CET 2008

Bruno Desthuilliers <bruno.42.desthuilliers at> wrote:
> fact 1: CPython compiles source code to byte-code.
> fact 2: CPython executes this byte-code.
> fact 3: Sun's JDK compiles source code to byte-code.
> fact 4: Sun's JDK executes this byte-code.
> Care to prove me wrong on any of these points ? Don't bother: you can't. 
> So my first assertion that "CPython is compiled to byte-code, which is 
> then executed by a VM" is true, and since the same assertion also stands 
> for Java (ie: sun's JDK), then the "just like" qualifier is true too. 
> Period.

#2 and #4 are wrong (or, at best, misleading).  Here, I'll fix them
for you:

Fact 2: CPython interprets the bytecode.

Fact 4: Sun's JVM does some interpretation of the bytecode, but also
compiles some of the bytecode to native code and executes the
resulting native code.

These distinctions can be important and it's intellectually dishonest
to gloss over them.

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