Programming

Hi,

We've been using a perl script to extract datas from several logs to generate a report. I've been asked to rewrite the code in C++. I want to know if it is wise to have a code in C++ and will it be more faster than Perl?

Most perl scripts are portable to a wide selection of operating systems. A C++ program would have to be rebuilt to move it to a different machine architecture and might need to be rebuilt to move it to a different operating system even if they both run on the same hardware.

If you are a competent C++ programmer, you should be able to write a C++ program that will run faster than an interpretive language like perl to perform the same job. (However, that doesn't mean that writing the C++ code to get an improved level of performance over a perl script will necessarily be easy.)

It may be a good idea to find out what the bottleneck in the perl program is, before you get carried away. Reimplementing a flawed algorithm in a faster language may give you little to no benefit.

Take a decision only after profiling your program, using either one of the standard distribution profilers or one from CPAN.

I think it's a fine idea to write the program to C++. Yes, a C++ program doing the same logic as a perl program will be faster. But I agree there may be a bottleneck in the perl program that could be fixed.

Normally, I do a short task using bash. But once it gets to a certain level of complexity, I move to C. It runs faster, but that's not the main point. It's so much easier to maintain a complex program in C than a complex program in a scripting language. The same logic applies to perl, which is kind of infamous for somehow leading to undecipherable code. On the other hand, there are large applications written in perl.
For the most part, I disagree with this assertion. If there is a graphic front end, it is often tricky writing multi-platform code. But for processing a log file, the program should compile on any platform, assuming the programmer is competent.

Why were you asked to rewrite in C++? Was any justification given? Or is it just a blind assumption that it will be better?

I am going to assume that the perl script is a complicated beast.

I would seriously advise against a rewrite, except as a last resort. Complex code that works well is usually the result of a lot of testing and debugging. I would not cast it aside lightly.

I concur with Corona688 and elixir_sinari. Profile your current script and see where it spends most of its time. Then, have a look at those subroutines and see if they can be optimized in perl. Even if that's insufficient, a complete rewrite is still not your only alternative. The critical perl sections can be re-implemented in C and loaded by the perl interpreter like any other module: perlxs.

One thing is certain: advice on whether to rewrite code from people who do not know what that code does isn't worth much. Perhaps not even the proverbial 2 cents.

Regards,
Alister

That's a good point. If the perl is a complex beast, any kind of "fix" could be problematic. If you can't figure out the logic, it will be difficult to rewrite in some other language. It's hard to say more without knowing what the problem is or seeing the code. My main point is that there are differences between languages, and that certain languages are better suited for more complex, large-scale systems, other languages more suited for medium tasks, others for tiny tasks. There can come a point where a program is poorly supported by the existing programming language, too slow, lacking functionality, or too hard to maintain.