Re: [Boost-build] Conditional updating using NOUPDATE

Subject: Re: [Boost-build] Conditional updating using NOUPDATE
From: Edward Mitchell (erm410_at_[hidden])
Date: 2013-04-26 09:52:44

On 04/25/2013 12:23 AM, Steven Watanabe wrote:
> AMDG
>
> On 04/24/2013 09:06 PM, Edward Mitchell wrote:
>> Thank you for your quick response. However, I am not quite sure that
>> what you are saying is different from what I am doing.
>>
> The difference is the level that things happen at.
> actions touch and rule touch both operate on Jam targets,
> which cando.scrape creates Boost.Build metatargets.
> The argument of NOUPDATE is expected to be a list
> of Jam targets.  (actions touch and rule touch are
> two parts of the same rule.  If both are defined,
> both will be run.)
>
>> To be clearer I have several jamfiles that all are `using cando` and
>> call the rule `cando.scrape` at parse time. This rule, defined in a
>> toolset module cando.jam, runs the python script and defines the target
>> that I am having trouble with. I thought that by using a toolset module
>> the all uppercase (jam level) rules would be available to use, e.g. I
>> have used "ECHO" and "echo" equally effectively in cando.jam.
>>
> They are available.  *However*, the built-in rules
> that operate on targets do *not* work on Boost.Build
> metatargets.
>
>> Are you saying I need a new main target rule, with a custom file
>> type/generator and everything to make this work? Or am I missing
>> something obvious?
>>
>> To sum up:
>>
>> In jamfile.jam, I have the lines:
>> using cando ;
>> cando.scrape $(__file__:D) ;
>> always scrape_flag.h ;
>>
>> And in cando.jam I have the code posted in the previous email.
>>
>> I am afraid I am terribly confused by all this, I hope you can clear it
>> up for me.
>>
> Please see
> http://www.boost.org/boost-build2/doc/html/bbv2/extender.html#bbv2.extender.intro
> for a discussion of the target layers.
>
> In Christ,
> Steven Watanabe
>
> _______________________________________________
> Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost-build
Steven,

Thank you again for clearing this up and taking the time to help me! I 
was under the impression that rules that took targets could handle any 
level of target, not just Jam targets. Things are now working as 
expected and I feel a lot more confident about my further efforts to 
extend Boost-build to meet the needs of this project.

Thanks again,
Ed