[vox-tech] Make with _possibly_ cascading dependencies

[Bill Kendrick]

This isn't Linux-related, but is make-related ("nmake", specificlaly),
so I thought I'd ask here. :^)

In the mobile phone software world, you often end up building numerous
versions of the same app, to address differences between handsets
(e.g., use different art assets, depending on the screen sizes; handset
screens differ wildly in size and aspect ratio).

An application I'm working on has had the same data shared across all
builds (let's name a few of the builds "M", "L" and "XL", for example).
In my project, I have a data file that gets used during the build
process.  We now need to be able to use _build-specific_ versions of this
file, for some builds.  (Honestly, it's insanely more complicated than all
this, but I'm trying to boil it down, for consumption :^) )

Example:

  foo.xyz : DATA\foo.in
  	process DATA\foo.in > foo.xyz

Now, I want to be able to check whether there's a build-specific dependency.
If so, I want to use it, rather than the 'default' one.

e.g.:

  foo.xyz : DATA\$(SIZE)\foo.in    # Where SIZE is "M", "L" or "XL"
  	process DATA\$(SIZE)\foo.in > foo.xyz

If and only if it exists... otherwise, use the default one, as shown above.


My first idea is to just junk the dependency part of the target...
when I make my builds, I'm always cleaning everything first, anyway.  *sigh*

e.g.:

  foo.xyz :
  	# Do the default first:
  	process DATA\foo.in > foo.xyz
  	# Then try to override it with a build-specific one, if it exists:
  	if EXISTS DATA\$(SIZE)\foo.in   process DATA\$(SIZE)\foo.in > foo.xyz


An even worse variation on the above is to generate a temp file first:

  foo.xyz : DATA\foo.in.temp
  	process DATA\foo.in.temp > foo.xyz

  foo.in.temp :
  	# Copy the default file into a temp file, first
  	copy DATA\foo.in DATA\foo.in.temp
  	# Overwrite the temp file with a build-specific one, if it exists:
  	copy DATA\$(SIZE)\foo.in DATA\foo.in.temp

Ideas?

-- 
-bill!
bill at newbreedsoftware.com
http://www.newbreedsoftware.com/