[M3devel] "SYSTEM_LIBS contains X11"?

[Olaf Wagner]

Quoting Jay K <jay.krell at cornell.edu>:

> I kind of think the original authors had in mind:
>
>    if SYSTEM_LIBS contains "X11"
>
> as a useful construct..but I'm not sure..and no matter their intentions,
> it seems at first promising but then actually inadequate, and that maybe
> we need something to replace what it seems to promise.
>
> IN PARTICULAR:
>
> If something is directly dependent on X11, then it seems reasonable
> to do m3makefile:
>
> if SYSTEM_LIBS contains "X11"
>
> ..everything..
>
> library("foo")
>
> end
>
> but then it seems to me that clients of library("foo") shouldn't
> know or care that foo depends on X11.
>
> It seems like you maybe should be able to do like:
>
> if SYSTEM_LIBS contains "X11"
>
> ..everything..
>
> library("foo")
>
> else
>
> no_library("foo") % or something
>
> end
>
> and then when I have:
>
> import("foo")
>
> library("fooclient")
>
> I should probably just a warning like:
>
> "not building fooclient because foo is explicitly not available"
> "explicitly not available" as opposed to "seems to just be missing,
> perhaps you forgot to build it first?"
>
> In particular, "no_library" would need to be "active" and leave a   
> mark of some sort.
>
> ?
>
> In the meantime I'm considering some special case thing, like
>
> configfile:
>
>   HAS_GUI = TRUE
>
> or
>
>   HAS_TRESTLE = TRUE
>
> or config.common:
>
>  if not defined("HAS_TRESTLE")
>   HAS_TRESTLE = TRUE
>
>  end
>
> ??

HAS_TRESTLE sounds OK to me, as there may be other GUI toolkits like gtk.
I'm not sure though why we shouldn't just depend on m3-ui/ui to be
available. Is it just the error message?

Olaf
-- 
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