Re: betterC question
On Thursday, 19 November 2020 at 14:34:38 UTC, Adam D. Ruppe wrote: On Thursday, 19 November 2020 at 00:20:50 UTC, Dibyendu Majumdar wrote: Okay thanks. Bad idea IMO. That's kinda how I see C taking the address of various things implicitly. To be honest it seems irrelevant what C does.
Re: betterC question
On Thursday, 19 November 2020 at 14:34:38 UTC, Adam D. Ruppe wrote: On Thursday, 19 November 2020 at 00:20:50 UTC, Dibyendu Majumdar wrote: Okay thanks. Bad idea IMO. That's kinda how I see C taking the address of various things implicitly. good example
Re: betterC question
On Thursday, 19 November 2020 at 00:20:50 UTC, Dibyendu Majumdar wrote: Okay thanks. Bad idea IMO. That's kinda how I see C taking the address of various things implicitly.
Re: betterC question
On Thursday, 19 November 2020 at 00:07:12 UTC, Dibyendu Majumdar
wrote:
I have simple test program:
import core.stdc.stdio : printf;
void test() {
int* a;
printf("a == null %d\n", a == null);
}
int function() fp = test;
extern (C) void main() {
fp();
}
Why do I get:
\d\dmd-2.092.1\windows\bin64\dmd.exe -betterC tests.d
tests.d(5): Error: printf cannot be interpreted at compile
time, because it has no available source code
This is on Windows
IMO another problem here is that `function` and `delegate` are
special cases of the `*` postfix. With a syntax like
int()* fp = test
it would be more obvious to new comers that `&` is missing.
This is a syntax I experiment in STYX for example [1].
Note that then there's also the problem with functions pointers
requiring a context. This context is not necessarily a `this`
(for closures it's a frame obviously).
[1]
https://gitlab.com/basile.b/styx/-/blob/master/tests/backend/function_pointers.sx#L10
Re: betterC question
On Thursday, 19 November 2020 at 09:23:25 UTC, Jacob Carlborg wrote: Yes, calling `writeln` like that is a bad idea. That was a bad example. But the actual reason is, this is how D implements properties [1]. Any function that doesn't take an argument can be called without parentheses. Any function which takes a single argument can be called like setting a field. I think that properties on an object are a special case - but treating an random function identifier as callable is still bad.
Re: betterC question
On Thursday, 19 November 2020 at 01:42:16 UTC, Mike Parker wrote:
On Thursday, 19 November 2020 at 00:20:50 UTC, Dibyendu
Majumdar wrote:
On Thursday, 19 November 2020 at 00:18:54 UTC, rikki
cattermole wrote:
You don't need the brackets to call a function (and with a
little help from UFCS):
void main() {
import std.stdio;
"Hello!".writeln;
writeln;
}
Okay thanks. Bad idea IMO.
Imagine what range pipelines would look like without it. This
is one of my favorite D features.
Well Java and C# have streams and it looks perfectly fine without
this kind of syntax.
Re: betterC question
On Thursday, 19 November 2020 at 00:20:50 UTC, Dibyendu Majumdar
wrote:
On Thursday, 19 November 2020 at 00:18:54 UTC, rikki cattermole
You don't need the brackets to call a function (and with a
little help from UFCS):
void main() {
import std.stdio;
"Hello!".writeln;
writeln;
}
Okay thanks. Bad idea IMO.
Yes, calling `writeln` like that is a bad idea. That was a bad
example.
But the actual reason is, this is how D implements properties
[1]. Any function that doesn't take an argument can be called
without parentheses. Any function which takes a single argument
can be called like setting a field. Here's an example:
struct Color
{
private uint hex;
int red()
out(result; result >= 0 && result <= 255) // assert that the
result is within bounds
{
return (hex & 0xFF) >> 16;
}
void red(int value)
in(value >= 0 && value <= 255) // assert that the value is
within bounds
{
hex = (hex & 0x00) | (value << 16);
}
// similar functions for green and blue
}
void main()
{
Color color;
color.red = 255;
assert(color.red == 255);
}
[1] https://en.wikipedia.org/wiki/Property_(programming)
--
/Jacob Carlborg
Re: betterC question
On Thursday, 19 November 2020 at 00:20:50 UTC, Dibyendu Majumdar
wrote:
On Thursday, 19 November 2020 at 00:18:54 UTC, rikki cattermole
wrote:
You don't need the brackets to call a function (and with a
little help from UFCS):
void main() {
import std.stdio;
"Hello!".writeln;
writeln;
}
Okay thanks. Bad idea IMO.
Imagine what range pipelines would look like without it. This is
one of my favorite D features.
Re: betterC question
On Thursday, 19 November 2020 at 00:18:54 UTC, rikki cattermole
wrote:
You don't need the brackets to call a function (and with a
little help from UFCS):
void main() {
import std.stdio;
"Hello!".writeln;
writeln;
}
Okay thanks. Bad idea IMO.
Re: betterC question
On 19/11/2020 1:11 PM, Dibyendu Majumdar wrote:
On Thursday, 19 November 2020 at 00:08:59 UTC, Adam D. Ruppe wrote:
On Thursday, 19 November 2020 at 00:07:12 UTC, Dibyendu Majumdar wrote:
int function() fp = test;
This tries to *call* the function test and assign its return value to fp.
Really? why does it do that?
You don't need the brackets to call a function (and with a little help
from UFCS):
void main() {
import std.stdio;
"Hello!".writeln;
writeln;
}
Re: betterC question
On Thursday, 19 November 2020 at 00:08:59 UTC, Adam D. Ruppe wrote: On Thursday, 19 November 2020 at 00:07:12 UTC, Dibyendu Majumdar wrote: int function() fp = test; You want to get the address. Okay that works. Thanks
Re: betterC question
On Thursday, 19 November 2020 at 00:08:59 UTC, Adam D. Ruppe wrote: On Thursday, 19 November 2020 at 00:07:12 UTC, Dibyendu Majumdar wrote: int function() fp = test; This tries to *call* the function test and assign its return value to fp. Really? why does it do that? You want to get the address.
Re: betterC question
On Thursday, 19 November 2020 at 00:07:12 UTC, Dibyendu Majumdar wrote: int function() fp = test; This tries to *call* the function test and assign its return value to fp. You want to get the address.
betterC question
I have simple test program:
import core.stdc.stdio : printf;
void test() {
int* a;
printf("a == null %d\n", a == null);
}
int function() fp = test;
extern (C) void main() {
fp();
}
Why do I get:
\d\dmd-2.092.1\windows\bin64\dmd.exe -betterC tests.d
tests.d(5): Error: printf cannot be interpreted at compile time,
because it has no available source code
This is on Windows
