Zig's Andrew Kelley: "The compiler is too dam slow, that's why we have bugs..."

[H. S. Teoh]

On Tue, Jan 30, 2024 at 12:25:24PM +0000, deadalnix via Digitalmars-d wrote:
[...]
> The question can better be asked in the following form: if we want to
> reduce errors, do we slow down development speed, in such a way that
> we can be more careful to not introduce problems at every steps along
> the way, or do we speed things up, such as it is faster to fix bugs,
> and therefore more can be fixed.
> 
> The usual answer most would give in the software industry is that one
> needs to slow down and be more careful. But this is not what the data
> ended up showing. Quite the opposite in fact!
[...]

My experience confirms this.  When your code-compile-test cycle is slow,
you tend to spend more time to write more code / make more changes
before compiling and running it.  It's simple practicality: making only
few changes means more compile cycles, which means more time spent
waiting.  Making more changes means less time spent waiting for the
compile cycle.

But since more changes are made, there's more room for bugs.  And the
more changes you make means the more combinations you need to test
before you discover failing cases.  Due to combinatorial explosion, the
chances of catching these cases decrease exponentially the longer the
compile cycle is.

When the compile cycle is fast, the incentives shift the other way: you
make less changes before compile + test, so you get faster feedback on
any obvious bugs in your changes. So problems get caught early and get
fixed before they accumulate.  Your mind is also fresher when it's only
a small amount of changes -- you still remember the details of what's
happening, so you can fix it faster and more accurately.  And since
there are less combinations to test with each small change, you're more
likely to find failing cases early.

tl;dr: DMD's fast compile times is a killer feature.  It's why I still
use it in spite of its suboptimal codegen.


T

-- 
Let X be the set not defined by this sentence...