Re: [Boost-build] SHELL and trailing newlines

From: Johan Nilsson (r.johan.nilsson_at_[hidden])
Date: 2006-10-05 03:25:54

Rene Rivera wrote:
> Johan Nilsson wrote:
>> "Rene Rivera" <grafikrobot_at_[hidden]> skrev i meddelandet
>> news:45240ADA.5090902_at_gmail.com...
>>> Johan Nilsson wrote:
>>>> "Rene Rivera" <grafikrobot_at_[hidden]> skrev i meddelandet
>>>> news:452406C8.6010104_at_gmail.com...
>>>>
>>>>> SHELL/COMMAND to act as the CLI shell do. Perhaps an
>>>>> "eol-delimited-output":
>>>>>
>>>>>   LIBXML_INCLUDES = [ SHELL "pkg-config --cflags libxml-2.0" :
>>>>> eol-delimited-output ] ;
>>>>>
>>>>> One might want to implement a 'ws-delimited-output' at the same
>>>>> time :-)
>>>> Why not use MATCH on the output to remove whatever you want? Or am
>>>> I missing
>>>> something?
>>> Not missing anything :-) One advantage to doing this at the SHELL
>>> level is that it will use less memory, because it can parse the
>>> output as it comes in and hence saves of having the possibly big
>>> output string around.
>>
>> Ok, how about simply allowing a regex expression as the delimiter
>> parameter,
>
> Sure. I suppose you have some use cases?

No, what I am suggesting is generally known as premature generalization ;-)

(In other words, thinking out loudly)

> And hence why you are
> suggesting it. Personally I have a need for smarter parsing of SHELL
> output than just regex delimited.

Callbacks into user-defined rules for each (regex-specified) delimited item 
(don't know enough about Jam to figure out if it's possible)?

-----------
rule shell-cb ( item )
{
    if $(item) in $(interesting-items)
    {
        echo FOUND: $(item) ;
        return $(item) ;
    }
    else
    {
        echo IGNORED: $(item) ;
        return "" ;
    }
}

local separator-regex = [\r\n]+ ;

local interesting-output =  [ SHELL "foo.exe" : $(separator-regex) : 
$(__name__).shell-cb ] ;
-----------

As I said previously, just thinking out loud. IIRC there was also an issue 
with stderr not being captured?

// Johan