[CMake] Add a simple suffix rule to makefile via cmake?

[James Bigler]

Christopher Lang wrote:
> Hi,
> 
> is it possible to add a custom suffix rule to a makefile like:
> 
> .po.mo:
> 	$(MSGFMT) -o $@ $<
> 
> 
> Will the following do?
> 
> ADD_CUSTOM_TARGET (.po.mo
> 	...
> )

This would be nice, but the feature doesn't exist as far as I know.  You 
could accomplish something similar (but not as handy) with a macro:

MACRO(ADD_PO_MO_TARGET _file)
   # You'll need to figure out how to make the output name.  See
   # documentation for STRING and GET_FILENAME_COMPONENT.
   # CMAKE_CURRENT_BINARY_DIR and CMAKE_CURRENT_SOURCE_DIR are also
   # useful variables to consider
   STRING(REPLACE .po .mo output_name)
   # You want ADD_CUSTOM_COMMAND instead of ADD_CUSTOM_TARGET since this
   # will produce an output file.
   ADD_CUSTOM_COMMAND(OUTPUT ${output_name}
     COMMAND ${MSGFMT} ARGS -o ${output_name} ${_file}
     DEPENDS ${_file}
     COMMENT "Compiling ${output_name} from ${_file}"
   )
ENDMACRO(ADD_PO_MO_TARGET)

Just call the macro now for ever .po file in your system.  This could be 
facilitated with a for loop.

James