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This is probably the best summary of functional programming, written by the best "pragmatical" programmer of the world. I wonder how much Haskell code Carmack m

This is probably the best summary of functional programming, written by the best "pragmatical" programmer of the world. I wonder how much Haskell code Carmack must have written to reach this kind of knowledge... and whether it is open source. It would be a good read for the weekends. BTW, I think the pure keyword in C++ would be great. I wrote some C++ in school, and even I can tell that const, as applied to functions, could use some retirement. It's nonsense to keep this unmodified, stateless so to speak, but allow global variable assignation, and so on.

evincarofautumn 14y ago
Not entirely nonsense—immutability is helpful even in the absence of referential transparency—but still, a “pure” keyword would be great. Now, what I’d really like is for the type system to be flipped on its head with respect to immutability: make “const” the default and explicitly qualify mutable types with “mutable”. A guy can dream…
- kibwen 14y ago
  Perhaps you should take a look at Rust.[1] It's a pretty compelling union of functional and procedural paradigms, plus: immutability by default, the ability to annotate functions as pure, pattern matching, option types, good C compatibility, strong support for concurrency, high-level memory management that guarantees memory safety and that doesn't require tedious memory micromanagement (while retaining the option to just GC everything and forget about it), and a lot more. Still alpha software at the moment, though. [1] http://www.rust-lang.org/ http://www.rust-lang.org/
  - evincarofautumn 14y ago
    I’ve looked into it. Seems like a promising language, and it does quite a few things right. Still, I feel a bit uncomfortable endorsing it wholesale while I work on my own linguistic magnum opus. ;)
  - zem 14y ago
    yeah, i'm excited about rust. i'm currently diving into d, and while it is a lot nicer than c++ (and i've barely started discovering all its features), i really miss pattern matching, option types and everything-is-an-expression, which i've gotten used to from other languages. it looks like rust supports all three of those features, which already puts it closer to my sweet spot.
heretohelp 14y ago
const has legacy reasons for its behavior, some of them relating to DMA and embedded environments.
el_presidente 14y ago
GCC has a 'pure' attribute. I don't know if it's only used for optimization, but it also serves as a kind of comment for whoever looks at the function in the future.
- copx 14y ago
  "pure" and "const" are GCC function attributes which are supposed to help the optimizer. Confusingly enough "const" demands a higher level of purity than "pure".. I would never use those attributes except - maybe - in the most critical loops and then only with a big "WARNING!!!" sign. Why? GCC does not / cannot enforce the guarantees given by "const" and "pure" yet the optimizer always assumes they are true. I.e. accidentally reduce the purity of a function decorated in this way.. and you might create very hard to find bugs. This is a general problem in C and C++, those languages simply weren't designed to enforce such contracts. C99's "restrict" has the same problem.
  - jhasse 14y ago
    Since when is "const" a GCC function attribute?
    - scott_s 14y ago
      http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html This is, of course, in addition to its other meanings in the language.

evincarofautumn 14y ago

Not entirely nonsense—immutability is helpful even in the absence of referential transparency—but still, a “pure” keyword would be great. Now, what I’d really like is for the type system to be flipped on its head with respect to immutability: make “const” the default and explicitly qualify mutable types with “mutable”. A guy can dream…

kibwen 14y ago
Perhaps you should take a look at Rust.[1] It's a pretty compelling union of functional and procedural paradigms, plus: immutability by default, the ability to annotate functions as pure, pattern matching, option types, good C compatibility, strong support for concurrency, high-level memory management that guarantees memory safety and that doesn't require tedious memory micromanagement (while retaining the option to just GC everything and forget about it), and a lot more. Still alpha software at the moment, though. [1] http://www.rust-lang.org/ http://www.rust-lang.org/
- evincarofautumn 14y ago
  I’ve looked into it. Seems like a promising language, and it does quite a few things right. Still, I feel a bit uncomfortable endorsing it wholesale while I work on my own linguistic magnum opus. ;)
- zem 14y ago
  yeah, i'm excited about rust. i'm currently diving into d, and while it is a lot nicer than c++ (and i've barely started discovering all its features), i really miss pattern matching, option types and everything-is-an-expression, which i've gotten used to from other languages. it looks like rust supports all three of those features, which already puts it closer to my sweet spot.

heretohelp 14y ago

const has legacy reasons for its behavior, some of them relating to DMA and embedded environments.

el_presidente 14y ago

GCC has a 'pure' attribute. I don't know if it's only used for optimization, but it also serves as a kind of comment for whoever looks at the function in the future.

copx 14y ago
"pure" and "const" are GCC function attributes which are supposed to help the optimizer. Confusingly enough "const" demands a higher level of purity than "pure".. I would never use those attributes except - maybe - in the most critical loops and then only with a big "WARNING!!!" sign. Why? GCC does not / cannot enforce the guarantees given by "const" and "pure" yet the optimizer always assumes they are true. I.e. accidentally reduce the purity of a function decorated in this way.. and you might create very hard to find bugs. This is a general problem in C and C++, those languages simply weren't designed to enforce such contracts. C99's "restrict" has the same problem.
- jhasse 14y ago
  Since when is "const" a GCC function attribute?
  - scott_s 14y ago
    http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html This is, of course, in addition to its other meanings in the language.