C for all: Parametric polymorphism in C

http://plg.uwaterloo.ca/~cforall/

by r0naa • 11 years ago

68 25 11 years ago

plg.uwaterloo.ca

anon3_• 11 years ago

We're reaping the benefits of C's resistance to feature bloat.

C powers the daemons and operating systems of the world.

When you're working in the field, C's transparency and absence of esoteric programming voodoo is a feature, not deficit.

Interest posting made today similar: https://news.ycombinator.com/item?id=9827051

the_why_of_y2• 11 years ago

How does "undefined behavior" not qualify as "esoteric programming voodoo"?

xamuel• 11 years ago

UB is not something that a competent programmer does intentionally.

You shouldn't ever run into a situation where you'd tell your fellow programmer, "Hey, on line 300 here, you're doing UB, stop it", only for them to say "No, I'll do UB if I please".

With C++ on the other hand, you could very well run into situations where you plead with your fellow programmer, e.g., "please stop overloading operators in this opaque and unmaintainable way", and then they tell you, "so what, that's our in-house style and it has official language blessing".

wcummings• 11 years ago

In the field?

huhtenberg• 11 years ago

This has no chances of going mainstream, but this is a thoughtful and careful exploration of a C extension. Type system [1] is nicely done (though I think it looks a bit clunky in application).

Tangentially related - once you worked with C long enough, the lack of of "templates" becomes pretty obvious. If you need two functions that do the same thing for two different input types, you have two options - wrap it into a multiline define or use one generic function and use a callback to deal with type differences, a'la qsort(). Neither is exactly ideal.

Does anyone know of C dialects with some form of template support?

[1] http://plg.uwaterloo.ca/~cforall/typesystem.html

Rexxar• 11 years ago

Does anyone know of C dialects with some form of template support?

C++, but I'm sure it's not the answer you want.

It would be nice if C++ compilers had more fine grained switch to activate only functionality people want to use. It would be better, IMHO, than creating a new incompatible language each time. A "C + template" would be useful for many people who don't want the full C++.

Qantourisc• 11 years ago

How does the extra functionality impact the final binary ? Or do the compilers add extra things you don't need even if you don't use them ?

okasaki• 11 years ago

Like what? You can turn off exceptions.

AlphaSite• 11 years ago

C11 does have _Generic to make those multiple functions a little easier.

pkhuong• 11 years ago

There's a third (still clunky) option: `#define` parameters before `#include`ing a template file.

pavlov2• 11 years ago

This is almost 20 years old, isn't it?

The text refers to a C9x standard, so it must predate the standardization of C99.

pdpi• 11 years ago

Nope, they link to a draft of the spec (http://plg.uwaterloo.ca/~cforall/refrat.pdf) which dates from May this year.

pavlov2• 11 years ago

Interesting. I guess it's been resurrected because most of the other materials are dated between 1997 and 2003.

kazinator• 11 years ago

Structure Prototypes: This was proposed in February 1998 in comp.std.c by bill@cafe.net (Kaz Kylheku). The idea is that eliding member names in a structure prevents access to the members.

Hey, thanks for the credit.

agumonkey• 11 years ago

Just when I was looking for C-with-tuple-and-destruct. Brilliant.

filereaper• 11 years ago

Peter Buhr also teaches CS343: Concurrent and Parallel Programming.

CS343 uses uC++ which has coroutines, threads, monitors and other constructs used to teach advanced control flow.

[0] http://plg.uwaterloo.ca/~usystem/uC++.html

[1] https://www.student.cs.uwaterloo.ca/~cs343/

[2] http://plg.uwaterloo.ca/~usystem/pub/uSystem/uC++book.pdf

C for all: Parametric polymorphism in C

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