Re: Appending to variables

On Tuesday, June 23rd, 2026 at 9:25 AM, David Deutsch <[email protected]> wr=
ote:

> To translate what your command is "saying" to make:
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> make -f myfile.mk trlfn
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> equates to "read myfile.mk and then execute the recipe to produce the
> target trlfn".
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> But trlfn is not a target because it has no recipe.
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>  > Would there be no prerequisites for such cases?
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> Prerequisites are targets that need to be resolved before building the
> desired targets. They are not dynamic bits of code like in your example.
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>  > If I want to build my program with gcc, I might need to set compiler
> options by specifying what I want to the makefile.  How would it be a
> wrong idea?
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> That's an entirely separate topic. You typically set compiler flags with
> an environment variable. NOT with a target (.PHONY or otherwise)
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> I also slightly misread your makefile because it's so off-syntax:
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> trlfn: hopc +=3D --transliterate-file-names
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> This makes even less sense than I thought - if hopc is your executable,
> you cannot "add to it" with +=3D, which is an extension to an existing
> variable (although it might work slightly by accidend by just assuming
> that "hopc" is a string that you then append to)
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> The target shape that you want could be something like
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> # myfile.mk
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> hopc-result.trlfn:
>      hopc --transliterate-file-names
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> hopc-result.ndf:
>      hopc --node-files
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> hopc-result.trlfn.ndf:
>      hopc --transliterate-file-names --node-files
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> and then call it via
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> make -f myfile.mk hopc-result.trlfn
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> but that's overly contrived.
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> Anyhow - maybe what you're actually looking for here IS an environment
> variable?

hopc accumulates options for makeinfo. =20

Using multiple options, I would have something like

--html --split=3Dnode --transliterate-file-names --node-files


Then I would need the call=20


$(hmldir)/antares.html: $(srcs) | $$(@D)
=09makeinfo $(opts) --html $(hopc) -o $@ $<

What would you suggest?  Have looked at how emacs generates
its documentation and it uses a makefile that calls makeinfo.
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>  > I do not think I am using wrong tool for the job.
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> You're using make like a bash script. That's not inherently wrong, but
> what Make really wants to do is resolve dependency graphs to build
> targets via their recipes.
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> -David
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