4 ms·

I have a question that I have often wanted to ask of someone that knows something about declarative programming. In my day job, I spend most of my time worryin

I have a question that I have often wanted to ask of someone that knows something about declarative programming. In my day job, I spend most of my time worrying about trying to make my code run faster (I do low-level user-interface work - building the libraries that application UIs then use, so it's all about moving pixels as fast as possible, getting data to the app as fast as possible etc. If I need to make a SW blit run faster, I go into the function doing the blit, and I may replace some of the C code with some SSE-style vectorised assembler. Or I may choose to run an expensive SQL query once a day, storing the result in a binary file that is then used to feed application data requests, or other things of that nature. I just don't see how those kinds of optimisations could be done in a declarative language. Do I just have an unusual use-case, or are these languages seriously constrained with respect to the types of programs that they can be used for?

randomhunt 13y ago
The right tool for the job. I wouldn't try to cut a piece of wood to length by using a hammer. Declarative languages tend to lend themselves to being used at a much higher level, for example easily encoding rules regarding salary payments rather than low level bit twiddling.
maaku 13y ago
> I just don't see how those kinds of optimisations could be done in a declarative language. Not to be an ass, but why not? All of your examples are, in principle, doable in a declarative language.
- louthy 13y ago
  > Not to be an ass, but why not? He's not saying it can't be done, he wants to ask "someone that knows something about declarative programming".
jheriko 13y ago
its about trusting the compiler... performance oriented code is a surprisingly small amount of stuff, as reading hacker news constantly reminds me. (ps i work in games and vfx - similar restrictions) although i guess there is no reason why you can't make declarative performance constraints ...

randomhunt 13y ago

The right tool for the job. I wouldn't try to cut a piece of wood to length by using a hammer. Declarative languages tend to lend themselves to being used at a much higher level, for example easily encoding rules regarding salary payments rather than low level bit twiddling.

maaku 13y ago

> I just don't see how those kinds of optimisations could be done in a declarative language. Not to be an ass, but why not? All of your examples are, in principle, doable in a declarative language.

louthy 13y ago
> Not to be an ass, but why not? He's not saying it can't be done, he wants to ask "someone that knows something about declarative programming".

jheriko 13y ago

its about trusting the compiler... performance oriented code is a surprisingly small amount of stuff, as reading hacker news constantly reminds me. (ps i work in games and vfx - similar restrictions) although i guess there is no reason why you can't make declarative performance constraints ...