Re: [Boost-build] invalid/outdated comments & code in generators.jam

From: Vladimir Prus (ghost_at_[hidden])
Date: 2008-05-05 11:37:40

On Wednesday 30 April 2008 23:38:30 Jurko Gospodnetić wrote:
>    Hi all.
> 
>    generators.jam module seems to have traces of comments and 
> implementation related to special handling or some multiple target 
> generation cases which seems to have been implemented at one time but 
> then incompletely removed in revision 29361 (committed by Volodya).
> 
>    I'm attaching a patch (description: Removed some old corpse comments 
> and debugging output code related to functionality long removed in 
> revision 29361.) based on revision 44943 and if no one objects will 
> commit it.

Thanks for cleaning this up. I'm not sure if you've checked this in
already -- if not, please do.

> 
> 
>    Volodya, could you look at the following paragraph in its main module 
> comment and say if it is OK to remove it? Or should it be transformed 
> into something else? It seems outdated as the construct() rule no longer 
> takes any such parameter.
> -------------
>    That early conversion is not always desirable. Suppose a generator 
> got a source of type Y and must consume one target of type X_1 and one 
> target of type X_2. When converting Y to X_1 extra target of type Y_2 is 
> created. We should not try to convert it to type X_1, because if we do 
> so, the generator will get two targets of type X_1, and will be at loss 
> as to which one to use. Because of that, the 'construct' rule has a 
> parameter, telling if multiple targets can be returned. If the parameter 
> is false, conversion of extra targets is not performed.
> -------------

Yes, that's so old I don't even understand what is used to mean when it
meant anything.

>    Also, could you look at the paragraph above it which says '(Later 
> I'll document the rationale for trying extra target conversion at that 
> point)'? I'd fix if but I am still not at home with how this all 
> works... :-)

Oh, it seems like I've forgotten what this one means, too. I think that
an example was meant to be added, but I don't remember which.

- Volodya