Re: test[0u] of type bool[1u] does not have a boolean value
On Saturday, 29 June 2013 at 12:41:12 UTC, Namespace wrote:
Is this a bug or is it just me? It seems that the compiler
dereference wrong.
import std.stdio;
void foo(bool[1]* test) {
if (test[0])
test[0] = false;
}
void main()
{
bool[1] test = false;
foo(&test);
}
prints: Error: expression test[0u] of type bool[1u] does not
have a boolean value
This work:
if ((*test)[0])
test[0] = false;
bool[1]*: a pointer to a static array of bools of size 1.
Ergo test[0] is of type "bool[1]". Which can't be evaluated to
bool.
When you write "test[0] = false", that is actually an *array
assignement* (test[0] is the same as *test, which resolves to a
bool[1]), and yo are assigning false to *all* (in this case, 1)
elements of your array.
On the other hand, (*test)[0] first dereferences the pointer to
obtain the array, and then obtains the first element... The
assignment on the next line is still wrong though.
So I think it's just you ;)
But in your defense, (I think you have a C++ background?) the
declaration syntax from D to C++ is completely different...
Related: I think this might actually give you a compiler warning
about doing a range assign without slicing? Bearophile had
suggested this shouldn't work unless you actually type:
"test[0][] = false;"
But I prefer:
"test[0] []= false;"
I can't test right now: Does your code emit no warnings with -w ?
Re: test[0u] of type bool[1u] does not have a boolean value
I get this with -wi: bug.d(5): Warning: explicit element-wise assignment (test[0u])[] = false is bett er than test[0u] = false That helps a bit. But I thought that D dereferences automatically? ;)
Re: test[0u] of type bool[1u] does not have a boolean value
monarch_dodra: Related: I think this might actually give you a compiler warning about doing a range assign without slicing? Bearophile had suggested this shouldn't work unless you actually type: "test[0][] = false;" But I prefer: "test[0] []= false;" I can't test right now: Does your code emit no warnings with -w ? I have also suggested to have the "-wi" switch activated on default (as I think C# does, because people forget to use it all the time!), give a switch to disable on request the informational warnings (because once in a while you don't want warnings), and remove the -w switch (because it breaks the semantics of D programs) :-) http://d.puremagic.com/issues/show_bug.cgi?id=10321 Bye, bearophile
Re: test[0u] of type bool[1u] does not have a boolean value
On Saturday, 29 June 2013 at 13:11:10 UTC, bearophile wrote: monarch_dodra: Related: I think this might actually give you a compiler warning about doing a range assign without slicing? Bearophile had suggested this shouldn't work unless you actually type: "test[0][] = false;" But I prefer: "test[0] []= false;" I can't test right now: Does your code emit no warnings with -w ? I have also suggested to have the "-wi" switch activated on default (as I think C# does, because people forget to use it all the time!), give a switch to disable on request the informational warnings (because once in a while you don't want warnings), and remove the -w switch (because it breaks the semantics of D programs) :-) http://d.puremagic.com/issues/show_bug.cgi?id=10321 Bye, bearophile Thanks for the link. I actually wanted to state that I think you were one of the people who thought the above should be mandatory syntax? I do.
Re: test[0u] of type bool[1u] does not have a boolean value
On Saturday, 29 June 2013 at 12:57:07 UTC, Namespace wrote:
I get this with -wi:
bug.d(5): Warning: explicit element-wise assignment
(test[0u])[] = false is bett
er than test[0u] = false
That helps a bit. But I thought that D dereferences
automatically? ;)
Only when making a function call (AFAIK), eg: "p.foo();"
This also takes precedence over UFCS:
struct S
{
void foo(){writeln("val");}
}
void foo(S*){writeln("pointer");} //troll function trying to
hijack p.foo()
void main()
{
S* p = new S;
p.foo();
}
val
