[CMake] append command

[David Cole]

On Tue, Aug 9, 2011 at 3:34 PM, Alan W. Irwin <irwin at beluga.phys.uvic.ca> wrote:
> On 2011-08-09 17:19+0100 Glenn Coombs wrote:
>
>> Probably too late now and there isn't a bug filed so far as I know, but
>> one thing I would love to see added to cmake is an append command
>> so that lines like this:
>>
>>     set(CMAKE_EXE_LINKER_FLAGS_RELEASE "${CMAKE_EXE_LINKER_FLAGS_RELEASE}
>> /INCREMENTAL:NO")
>>
>> become shorter and easier to understand:
>>
>>     append(CMAKE_EXE_LINKER_FLAGS_RELEASE "/INCREMENTAL:NO")
>>
>> The existing syntax for the set command is just ugly when appending.  I
>> know you can define a macro or function to do this but I just
>> feel that it should be supported out of the box as it would make
>> CMakeLists.txt files more readable.
>>
>
> Hi Glenn:
>
> I am changing the subject line to keep discussion out of the
> bugfix thread as requested by Dave.
>
> It appears what you want is the list APPEND command for
> blank-delimited strings.  But then later someone will want to add
> other parts of the list functionality to blank-delimited strings as
> well such as removing items from the blank-delimited list.  Until you
> have two parallel list systems, one for blank delimited strings and
> one for semicolon-delimited strings (i.e., the current lists).
>
> I think most would reject the idea of having two parallel list systems
> with different delimiters so here is one possibility.
>
> For now just stick to list functionality, e.g.,
>
> list(APPEND CMAKE_EXE_LINKER_FLAGS_RELEASE "/INCREMENTAL:NO")
>
> and then change the semicolon delimiters to blanks using
>
> strings(REGEX REPLACE ...)
>
> once you have the list completely assembled.  Of course, that will not
> work for the corner case where the strings contain semicolons. So in
> the long term, the right thing to do with lists might be to allow a
> choice of delimiter if you could do that in such a way as to preserve
> backwards compatibility.
>
> Alan
> __________________________
> Alan W. Irwin
>
> Astronomical research affiliation with Department of Physics and Astronomy,
> University of Victoria (astrowww.phys.uvic.ca).
>
> Programming affiliations with the FreeEOS equation-of-state implementation
> for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
> package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
> Linux Links project (loll.sf.net); and the Linux Brochure Project
> (lbproject.sf.net).
> __________________________
>
> Linux-powered Science
> __________________________
>

The APPEND_STRING arg was recently added to the CMake command
set_property, because of a similar complaint about the APPEND arg with
properties that are typically space separated.

I'm not sure if an APPEND_STRING arg belongs in the "set" command, though...

I understand that a line like this:

    set(CMAKE_EXE_LINKER_FLAGS_RELEASE
"${CMAKE_EXE_LINKER_FLAGS_RELEASE} /INCREMENTAL:NO")

is visually "too long" because we use verbose variable naming, but it
is clear what it's doing, and it does work in all prior CMake
versions...

I tend toward keeping things as they are unless there's a strong
consensus that an addition like this would really improve things for
most CMake users.

Anybody else listening in here have an opinion?


Thanks,
David