Python vs. Lisp -- please explain

[Donn Cave]

Quoth Carl Friedrich Bolz <cfbolz at gmx.de>:
| Torsten Bronger wrote:
|> Well, I think that it's fair to say that there are by principle deep
|> run time differences between CPython and, say, a typical
|> C++-compiled program.  Your definition would not reproduce that.  I
|> think it's also fair to say that these differences should be known
|> if somebody tries to find the best tool for a job.  After all, they
|> include advantages, too.
|> 
|> My definiton would be that an interpreted language has in its
|> typical implementation an interpreting layer necessary for typical
|> hardware.  Of couse, now we could discuss what is "typical",
|> however, in practice one would know it, I think.  In case of Python:
|> CPython and all important modern processors.
|
| Well, if we take any modern Intel/AMD chip (which could be described as 
| "typical), a C++ program would fit the "interpreted" definition, since 
| the processor does not execute the machine code directly but rather 
| breaks it down into smaller microcode instruction -- a process that 
| could be described as intepretation.

That's irrelevant, though.  Note, "has in its typical implementation".
Your processor didn't come along with your C++ compiler, it's not part
of its implementation or even necessarily relevant to it - maybe some
potential for optimization, but the only hard and fast requirement is
that the processor must execute its instruction set as documented.

The reason this isn't just an abstruse philosophical argument where it
makes sense for us to obtusely cling to some indefensible point of view,
is that as the man points out, there are differences that we can't hide
forever from potential Python users.  The most obvious to me is that
your Python program essential includes its interpreter - can't go anywhere
without it, and any change to the interpreter is a change to the program.
There are various strategies to address this, but pretending that Python
isn't interpreted is not one of them.

	Donn Cave, donn at drizzle.com