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Comment by mahmud | Hacker News Reader

Compiler written in python, ruby and other "slow" .. languages going to take eternity to compile linux kernel.

What makes you think everyone is out to write a C compiler?

What make you think that I think this way? Linux kernel is just an example of relatively big program, where performance of the compiler is an important issue.

Another example of performance-sensitive application of compilers is background Java compiler in Eclipse - even for rather small programs it has to be fast. Ruby is 10-100 (actually more than that) times slower than C/Java, So if you optimizer (wriiten in C/Java/Haskell) needs 0.5 second to optimize code, same code will need (by very optimistic measure) 30 sec. Python not much better. Scheme a bit better (especially Stalin compiler), Lisp almost good.

Have you actually used Stalin? Compiling anything with it is shockingly slow. It does, of course, produce very fast programs—but it can take minutes to generate them, even in simple cases.

No I did not, butI read papers, written by the author. Indeed it is slow, but still be good for final compilation. Alas it is r4rs, and also I heard that it sometimes generate incorrect code. Still Scheme is better choice in my opinion for performance sensitive code, than ruby/python.

Stalin and Mlton are whole-program optimizing compilers. They take a bit longer than other compilers, but the results are impressive.

You probably missed the point - my concern is not the speed of compilation _of_ _the_ _compiler_ _itself_ - it is totally irrelevant, what is important is the performance of _created_ _compiler_, which is going to be ok, taking into account the quality of Stalins optimizer.

We can debate the performance of a hypothetical compiler for eternity, or we can cite examples; slow compilers written in a non-C language along with publicly available input data.

i.e. benchmarks or it didn't happen.

Man, you are being difficult. Ruby is well known to be a very slow language (if you want numbers check http://shootout.alioth.debian.org/u32q/benchmark.php?test=al...). Optimizing compilers are computationally demanding tasks, and the proof (albeit extreme one) is Stalin Scheme compiler, that can take minutes to compile code, but the result is sometimes faster than C/C++ code, or at least on par. Now, this compiler is written either in Scheme itself or in C i do not remember, but definetelt not in ruby. If it take to compile your code a minute for a compiler written in [C/Stalin Scheme] it will take at least ten minutes for one written in ruby.

And I do not know where you saw me saying C is the ultimate language for making compilers. I never said that, I do not think so, I just said python/ruby are bad for the task.

Sorry, I must have misunderstood your intent then. Python and Ruby are probably fast enough for compiler construction as well; I am sure they could be tweaked by an expert to yield acceptable performance, but I am just not such expert :-)

Background compilers do not need to perform heavy optimiztion, so can skip a lot of time consuming steps.

Even if they do not need a lot of optimizations, they still have to be fast. You would not like the performance would they be written in ruby.

And do not forget by the way that Ruby is a memory hog.

http://shootout.alioth.debian.org/u32q/benchmark.php?test=al...

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