"Strong typing vs. strong testing"

[Rui Maciel]

Pascal J. Bourguignon wrote:

> Nothing extraordinary here.  Common Lisp is more efficient than C.
> http://www.lrde.epita.fr/~didier/research/verna.06.ecoop.pdf
> http://portal.acm.org/citation.cfm?id=1144168

I don't know if you are intentionally trying to be deceitful or if you honestly didn't spent much 
time thinking about this issue.  To be brief I will only point out the following topics:


a) no language is inherently more or less efficient than any other language.  The efficiency 
aspect is only related to how those languages are implemented (i.e., the investments made in 
optimizing the compilers/interpreters)
b) Just because someone invested enough effort to optimize a specific implementation of language X 
to run, under a specific scenario, a benchmark faster than some other implementation of language Y 
it doesn't mean that language X's implementation outperforms or even matches every implementation 
of language Y under every conceivable scenario.


Regarding the links that you've provided, again I don't know if you intended to be dishonest or if 
you simply didn't read them.  The first link, entitled "Beating C in Scientific Computing 
Applications On the Behavior and Performance of LISP, Part 1", basically compares a highly 
optimized implementation of lisp (quite literally the "current state of the art in COMMON -LISP 
compiler technology") with a standard, run of the mill C implementation by performing a very 
specific benchmark.  If that wasn't enough, the C implementation they adopted to represent C was 
none other than GCC 4.0.3.  As we all know, the 4.0 branch of GCC was still experimental an ran 
notoriously worse than the 3.4 branch[1].

But even though you've ignored this, the article's authors haven't.  They've stated the following 
on their article:

<quote>
We must admit however that this point of view is not totally unjustified. Recent studies (Neuss, 
2003; Quam, 2005) on various numerical computation algorithms find that LISP code compiled with C 
MU - CL can run at 60% of the speed of equivalent C code.
</quote>

So, where exactly do you base your claims?


 
> Actually, it's hard to find a language that has no compiler generating
> faster code than C...

Once again, I don't know if you are intentionally trying to be deceitful.  If an undergraduate 
student happens to write a C compiler for a compiler class which employs no optimization 
whatsoevere then that will not mean that every single C compiler is incapable of generating 
efficient code. 


Rui Maciel


[1] http://coyotegulch.com/reviews/gcc4/index.html