Re: multiple assignments on one line?

[John Graham-Cumming]

Alexis Huxley wrote:
> I found a really ugly workaround; namely that if the external script
> does not write the assignments to stdout, but instead writes them
> to a temp file and just echos the name of the temp file on stdout, 
> then I can include that file with:
>
>         include $(shell name-of-my-script)
>
> but of course this is resulting in temporary files all over the
> place that I don't really feel are the Makefile's responsibility
> to clean up :-(

Well, you could do the following:

    TEMP_FILE := name_of_temporary_file

    -include $(TEMP_FILE)

    $(TEMP_FILE):
        @commands to write out the TEMP_FILE

The nice thing here is that GNU Make makes the file for you through its 
Makefile remaking feature.    It would be nice if it were possible to 
make GNU Make delete the $(TEMP_FILE) automatically but marking it is 
INTERMEDIATE has the undesired affect of getting GNU Make stuck in an 
infinite loop.

There is actually a way to hack that by doing the following:

    TEMP_FILE := name_of_temporary_file

    -include $(TEMP_FILE)

    $(TEMP_FILE):
        @commands to write out the TEMP_FILE
        @echo all $(MAKECMDGOALS): delete-$(TEMP_FILE) >> $(TEMP_FILE)

    .PHONY: delete-$(TEMP_FILE)
    delete-$(TEMP_FILE):
        @rm -f $(TEMP_FILE)

This assumes that the default goal is all, and works by adding a rule 
that will delete the temporary file when the goal being executed (either 
the default all or something in MAKECMDGOALS is done.

John.