Re: Conditionally set nothrow: for a block of code.

[Mike Franklin via Digitalmars-d-learn]

On Thursday, 24 May 2018 at 18:51:31 UTC, Mike Franklin wrote:
I'm trying to find a way to declare a block of code `nothrow:` 
when compiling with -betterC, but not `nothrow` when not 
compiling with -betterC.


The solution is needed for this PR:  
https://github.com/dlang/druntime/pull/2184/files#r188627707


Walter came up with a solution to this; put the code that is 
conditionally `nothrow` in a template and mix it in in the 
appropriate branch.


void test() { }

mixin template code()
{
extern(C) void main()
{
test();   // This should throw an error in -betterC 
because `main` is

  // `nothrow` but `test` isn't. It doesn't work
}
}

version(D_BetterC)
{
nothrow:
mixin code;
}
else
{
mixin code;
}

Thanks, Walter.

Mike

Re: Conditionally set nothrow: for a block of code.

[Nicholas Wilson via Digitalmars-d-learn]

On Thursday, 24 May 2018 at 18:51:31 UTC, Mike Franklin wrote:
I'm trying to find a way to declare a block of code `nothrow:` 
when compiling with -betterC, but not `nothrow` when not 
compiling with -betterC.


[...]


Not one now but, DIP 1012 will allow this as nothrow will become 
a regular enum attribute.

Re: Conditionally set nothrow: for a block of code.

[Uknown via Digitalmars-d-learn]

On Thursday, 24 May 2018 at 18:51:31 UTC, Mike Franklin wrote:
I'm trying to find a way to declare a block of code `nothrow:` 
when compiling with -betterC, but not `nothrow` when not 
compiling with -betterC.


The solution is needed for this PR:  
https://github.com/dlang/druntime/pull/2184/files#r188627707

[...]
Given that the PR above is for object.d, I can't turn the 
entire object.d source file into a string and conditionally mix 
that in.

 Does anyone have a solution to this?

Thanks,
Mike


I think conditional application of attributes would be something 
useful. Something like this:


version (D_BetterC)
enum BetterC = true;
else
enum BetterC = false;

nothrow!(BetterC):
...

Of course that would require a DIP though

Re: Conditionally set nothrow: for a block of code.

[Steven Schveighoffer via Digitalmars-d-learn]

On 5/24/18 2:51 PM, Mike Franklin wrote:

Given that the PR above is for object.d, I can't turn the entire 
object.d source file into a string and conditionally mix that in.  Does 
anyone have a solution to this?


My recommendation would have been the last one, but if that doesn't 
work, I don't think anything will that is... palatable.


The only other avenue you *could* explore is importing a file as a 
string and mixing the whole thing in (prepending "nothrow:" at the top).


Other than that, I think it's on to DIP territory.

-Steve

Conditionally set nothrow: for a block of code.

[Mike Franklin via Digitalmars-d-learn]

I'm trying to find a way to declare a block of code `nothrow:` 
when compiling with -betterC, but not `nothrow` when not 
compiling with -betterC.


The solution is needed for this PR:  
https://github.com/dlang/druntime/pull/2184/files#r188627707


Attempt #1
--
void test() { }

version(D_BetterC)
{
nothrow:
}

extern(C) void main()
{
test();   // This should throw an error in -betterC because 
`main` is

  // `nothrow` but `test` isn't. It doesn't work
}

Attempt #2
--
version(D_BetterC)
{
enum isNoThrow = true;
}
else
{
enum isNoThrow = false;
}

void test() { }

static if (isNoThrow)
{
nothrow:
}

extern(C) void main()
{
test();   // This should throw an error in -betterC because 
`main` is

  // `nothrow` but `test` isn't. It doesn't work
}

Attempt #3
--
version(D_BetterC)
{
enum nothrowValue = "nothrow:";
}
else
{
enum nothrowValue = "";
}

void test() { }

mixin(nothrowValue);

extern(C) void main()
{
test();   // This should throw an error in -betterC because 
`main` is

  // `nothrow` but `test` isn't. It doesn't work
}


Given that the PR above is for object.d, I can't turn the entire 
object.d source file into a string and conditionally mix that in. 
 Does anyone have a solution to this?


Thanks,
Mike