Georg Wrede wrote:
Don wrote:
Georg Wrede wrote:
Walter Bright wrote:
Lutger wrote:
what the hell...this code can't be human.
I was replaced by Colossus years ago.
Michael A. Jackson wouldn't approve 1175 gotos in 113 files.
It'd be really funny to pass it through one of those "code quality"
metrics, one of the ones with a ridiculously heavy penalty for using
goto. I think it'd tell you that DMD source is almost the
lowest-quality code on the planet. <g>
Yeah. But now I'm getting a bad conscience, this is beginning to look
like Walter-bashing... :-)
I think those code quality metrics are ridiculous. The prejudice against
'goto' is really just brainwashing and totally without basis.
Here's a recent link from Andrew Koenig, who really should know better.
http://dobbscodetalk.com/index.php?option=com_myblog&show=What-Dijkstra-said-was-harmful-about-goto-statements.html&Itemid=29
Can you see his fundamental mistake? He talks about "the program" (just
as Dijkstra said), but it's just not relevant for C/C++/D/Pascal/...
or any other structured programming language. Wherever he says "program"
you should substitute "function". And then the force of the argument
totally disappears.
The problem with goto in an unstructured language is that when you see a
label, you don't know where it came from. It could be anywhere in the
entire program (maybe a million lines of code!) And that's a complete
disaster. But in a structured language, you know it's from somewhere in
the function.
And this is no different from any other control structure. You ALWAYS
have to look at the whole scope you're in.
void foo(){
int n;
bool b = true;
while (b) {
if (n==4) { /* when do we get here? You have to read the whole
function to find out. Where does n get modified? */ }
:
:
:
}
}
Heck, even in inline ASM in D, you can't write the kind of spaghetti
code Dijkstra was complaining about. You always have local scope.
Yet, I personally have been so affected by anti-goto brainwashing that
I've never used goto in C, C++, or D. But I gradually realised that it
was just brainwashing. I've never experienced any problem with goto in ASM.
Actually, looking through the DMD source it becomes obvious that goto
is really not a problem at all. The lack of comments is much more of a
problem. (Especially with files with names like "e2ir.c". What the
heck is "fltables.c", "cdxxx.c", "elxxx.c" ?). Even so, it's mostly
not that difficult to understand.
I guess Walter has to keep alternating between ASM, C and D. And a lot
of ASM coding is nothing more than a bunch of MOV and JMP stuff. And
file naming conventions here look like what one typically finds in
development code (before some pre-publishing guy has tidyed it up with a
lot of global search&replaces). And, after all, the C files never were
meant to be public anyway.
Actually, the one interesting question might be, would rewriting this
code in a structured fashion (I mean, removing the gotos) make it
slower? (Not that I'd be suggesting Walter should do it. Just an
academic question.)
I doubt it'd affect the speed at all. It'd probably make it longer.
There are cases in DMD where it seems to make the control flow simpler.
