On 7/20/2014 3:27 AM, Dmitry Olshansky wrote:
Functional programming is full of simple recursion and it would be nice not to
stack overflow in debug builds.
Traditional FP languages don't have loops, and so must do recursion. D has
loops, even in pure functions, there's no reason not to use them.
Another use case is so-called threaded code interpreter, that can be done with
either computed gotos (and bunch of labels) or forced tail calls (and bunch of
functions). In both cases computed jump or tail call is indirect.
http://eli.thegreenplace.net/2012/07/12/computed-goto-for-efficient-dispatch-tables/
The computed goto is faster for two reasons, according to the article:
1.The switch does a bit more per iteration because of bounds checking.
2.The effects of hardware branch prediction.
(1) is eliminated with final switch. I know this optimization is not done with
dmd, but D doesn't need a new language feature because of that.
(2) with a bit more work, this could also be implemented as a compiler
optimization.
Both of these are worthy of bugzilla enhancement requests. I'd much rather
implement improvements as better code generation rather than more language features.
