On 28/03/14 23:49, Tommi wrote:
On 28 Mar 2014, at 14:27, Daniel Micay <danielmi...@gmail.com> wrote:
On 28/03/14 08:25 AM, Tommi wrote:
On 28 Mar 2014, at 05:56, Patrick Walton <pcwal...@mozilla.com> wrote:
I think that Rust should give you the ability to opt out of safety, but on a
per-operation basis. Having it as a compiler option is too much of a
sledgehammer: often you want some non-performance-critical bounds to be checked
in the name of safety, while you want some bounds checks to be turned off.
One other argument I can give for a "sledgehammer" feature like this is that it can be
used as a marketing tool against people who are worried about performance. You can say to those
people: "Look, if, at the end of the day, you decide that you'd rather take raw speed over
safety, then there's this compiler flag you can use to disable all runtime memory safety checking
in your code and get performance on par with C++".
It's called `unsafe`. There's a whole keyword reserved for it.
From a marketing standpoint, I don't think that the following sounds very
appealing:
"Look, if, at the end of the day, you'd rather choose raw speed over safety, then
you can go over all the hundreds of thousands of lines of code you have and change
everything to their unsafe, unchecked variants".
Flip it around: "Look, if, at the end of the day, you'd rather choose
safety over raw speed, then you can go over all the hundreds of
thousands of lines of code you have and change everything to their safe,
checked variants". Getting code correct is the first step to getting it
fast: it doesn't matter how fast a program runs if it's just doing the
wrong thing really quickly (e.g. exposing the users computer to hijacking).
Most code isn't in a tight inner loop, and so the piece-of-mind of it
being safe by default is worth the effort one has to put in to profile
and examine the very core logic that gets called millions of times. It's
much harder to use automated tools to find all of the memory safety
bugs. And anyway, as Daniel and Patrick say, if you don't need the
utmost safety, then Rust isn't the language you're looking for: things
like C++ work well in the speed department, at the cost of safety.
Huon
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