[Locke1689]

The author is mostly write about the usage cases of Haskell, but simply "systems" is a bit misleading because there are certain performance characteristics of lazy programs which make them bad choices for some systems programs. Any type of real-time system, for example, can suffer unpredictable performance in critical sections, which is pretty undesirable.

[dons]

Hard real time systems are probably the primary thing for which Haskell-as-is is directly unsuitable.

Haskell as an EDSL for generating hard real time, however, is very viable: http://corp.galois.com/blog/2010/9/22/copilot-a-dsl-for-moni...

[awj]

Not to argue the example, but Python's garbage collection disqualifies it for real-time systems as well. In fact, I'm having a hard time find a "system" task for which Python (as a language) is qualified by Haskell is not.

[Locke1689]

Python is not a systems programming language.

[microtonal]

Maybe not, but it is certainly used as one. Everything from package managers (yum) to operating system installers (Anaconda) have been written in Python.

Besides that, the grandparent is right: possibly every situation where Python was used as a systems programming language, Haskell could fit in (and more).

[Locke1689]

I think you're confused to what "systems" programming entails. User-space packaging with a bunch of scripts is not systems programming. OS installers is not systems programming.

To give you an example of what is systems programming, I have helped developed operating systems kernels, virtual machine monitors, and distributed networked systems. All of these things would be considered systems programming.

See http://en.wikipedia.org/wiki/System_programming for more information.

[microtonal]

That's just one definition. Read up on Ousterhout's dichotomy:

http://en.wikipedia.org/wiki/Ousterhouts_dichotomy

[Locke1689]

You should just read http://home.pacbell.net/ouster/scripting.html (his original paper) because all his statements about systems programming languages reinforces my claim that Python is not a systems programming language.

[jamwt]

While I agree with you that Haskell (or, really, any GC'd language) is unsuitable for real-time systems, I disagree that my statement about its excellent suitability for systems programming in general is misleading. There are many, many domains (read: most) that, in my experience, are called "systems programming" that have nothing to do with hard or soft real-time requirements.

Now, if I had stated that all conceivable systems programming domains are addressable with Haskell, that would have indeed been foolish.

[Locke1689]

Hm, good point -- I agree.