Re: [Boost-build] What is generators_prototype.py in the Boost Build root?

From: Vladimir Prus (ghost_at_[hidden])
Date: 2008-07-31 11:48:42

On Thursday 31 July 2008 18:54:20 Jurko Gospodnetiæ wrote:
>    Hi all.
> 
>    Anyone know what the generators_prototype.py file (located in the 
> Boost Build root folder) is for?
> 
>    At first glance it looks like some old leftover corpse from earlier 
> Boost Build implementation/design research?
> 
>    File seems to have been prepared by Dave Abrahams and I saw Volodya 
> mentioned in one of the code comments.

[This all was long ago, so below is my memory of things, which is not guaranteed
to be accurate in any way]

It's a code written by Dave to demonstrate an approach to selecting generators
he though was right. Back then, the generators code tried to do some smartness
in case there are several possible transformation chains -- and this smartness
was kinda ad-hoc, and not nicely documented, and not always worked. 

Then, Dave and I have disagreement on the best way from there. Dave argued for
a graph-based algorithm that would basically favour transformation graphs either
with smallest number of edges, or with minimum depth -- don't remember exactly.
This python file implements a prototype of that approach. I've argued that we
should convert all ambiguities into errors, and current code does roughly that.

- Volodya