[CMake] How Do I make a Custom Rule.

[Brad King]

Peter Kahn wrote:
> What is the right pattern to use in cmake to create a custom rule for
> converting a bunch of files?
> 
> 
>     In make I can define a custome rule for file types. 
>     What is the right way to do this in cmake? 
> 
> I can create a macro, but I'm unsure how to properly connect it to a
> target.  I can't seem to put it in a custom target.

Just list the output source files in a target:

http://www.cmake.org/Wiki/CMake_FAQ#How_can_I_generate_a_source_file_during_the_build.3F

In your code these lines:

    # Convert
    ADD_CUSTOM_COMMAND(
      OUTPUT    tmpFile
      COMMAND   transmogrify
      ARGS     ${TMP_MCFILE}
    )

do not make sense because it creates an output called "tmpFile" over and
over again in that FOREACH loop.  Each rule should have its own output,
and all outputs you want to generate should be listed in a target.

-Brad