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digitalmars.D - Can't put a const(char)[] into a char[]

reply Steven Schveighoffer <schveiguy yahoo.com> writes:
I just came across this. Can't believe there's not been more people 
finding this:

char[] buf = new char[100];
buf.formattedWrite("This is a number: %s", 5); // Error cannot put a 
const(char)[] into a char[]


OK, challenge accepted!

buf[0 .. myName.length] = myName[]; // Hey phobos, look, this is easy!

But no, of course -- autodecoding. >:(

https://issues.dlang.org/show_bug.cgi?id=18790

-Steve
Apr 21 2018
parent reply Nicholas Wilson <iamthewilsonator hotmail.com> writes:
On Saturday, 21 April 2018 at 22:34:39 UTC, Steven Schveighoffer 
wrote:

 I just came across this. Can't believe there's not been more 
 people finding this:

 char[] buf = new char[100];
 buf.formattedWrite("This is a number: %s", 5); // Error cannot 
 put a const(char)[] into a char[]


 OK, challenge accepted!

 buf[0 .. myName.length] = myName[]; // Hey phobos, look, this 
 is easy!

 But no, of course -- autodecoding. >:(

 https://issues.dlang.org/show_bug.cgi?id=18790

 -Steve


"Use .representation" would be the official answer for the second 
hack.
But this should absolutely work. It looks this looks the same 
thing as
https://issues.dlang.org/show_bug.cgi?id=18472#c10
---
enum s = "%1$s,%2$s".format("foo","bar");
---
phobos/std/range/primitives.d(405): Error: static assert:  
"Cannot put a const(char)[] into a Appender!string."
phobos/std/format.d(1184):        instantiated from here: 
put!(Appender!string, const(char)[])
/phobos/std/format.d(473):        instantiated from here: 
writeUpToNextSpec!(Appender!string)
phobos/std/format.d(6168):        instantiated from here: 
formattedWrite!(Appender!string, char, string, string)
main.d(5):        instantiated from here: format!(char, string, 
string)

18472 broke compilation of DCompute under -betterC when upgrading 
LDC to a newer DMDFE, I "fixed" it by not compiling with -betterC 
but then Mike Franklin (thanks!) discovered the above error after 
fixing the -betterC side of things.

I'm going to be extremely unhappy if I can't compile dcompute at 
all with the latest LDC.
IMO this is a priority 1 regression.
Apr 21 2018
parent reply Steven Schveighoffer <schveiguy yahoo.com> writes:
On 4/21/18 7:30 PM, Nicholas Wilson wrote:


 "Use .representation" would be the official answer for the second hack.


I have since discovered that I can use byCodeUnit, but I'm still annoyed 
that this is required.

I *think* that this is the only problem:

https://github.com/dlang/phobos/blob/master/std/range/primitives.d#L365

Essentially, here is the block:

     //Optional optimization block for straight up array to array copy.
     else static if (isDynamicArray!R && !isNarrowString!R && 
isDynamicArray!E && is(typeof(r[] = e[])))
     {
         immutable len = e.length;
         r[0 .. len] = e[];
         r = r[len .. $];
     }

If we just take out the !isNarrowString!R, I think it will just work, 
and probably cause no problems. I have NO IDEA why we are purposely 
shooting ourselves in the foot here.

I'm going to at least try it (PR forthcoming).

There are a few bits inside put that are supposed to cater to narrow 
strings, I'm not sure why it's not working.

-Steve
Apr 21 2018
parent Steven Schveighoffer <schveiguy yahoo.com> writes:
On 4/21/18 7:56 PM, Steven Schveighoffer wrote:


 I'm going to at least try it (PR forthcoming).


https://github.com/dlang/phobos/pull/6471

-Steve
Apr 21 2018