How to only pass an argument value to a Makefile target? - go

Question

I come from the NodeJS world so I consider the Makefile as the "scripts" part in an npm package.json, which may be wrong (or not ?) to do so.
So my idea is to automate repetitive actions when installing a new dependency by typing:
make install github.com/stretchr/testify
And find a way to get the github.com/stretchr/testify parameter without having to use the heavy parameter name-value declaration FOO=bar (=> make install DEP=github.com/stretchr/testify) generally suggested.
So, following this answer, I tried this:
install %:
go get $*
godep save ./...
git add Godeps vendor
git commit -m "godep: add $*"
but unsuccessfully: it runs go get without any param and git commit -m "godep: add".
Trials
1 - When I do that:
install %:
echo $*
I see my "github.com/stretchr/testify".
2 - When I do that:
install %:
go get ${*}
it loops twice and first run go get without any param, then runs go get github.com/stretchr/testify (as wished).
It looks like ${*} represents an "array" of params parsing characters groups after the target, the first one being the space between install and github.com/stretchr/testify and the second one being github.com/stretchr/testify.

Answer 1

You cannot use explicit targets and patterns in the same rule, so your rule % install: will not work.
You can do this with GNU make using the CMDGOALS variable, but it's very hackish and error-prone and I don't recommend it.
ARG := $(filter-out install,$(MAKECMDGOALS))
install:
go get $(ARG)
godep save ./...
git add Godeps vendor
git commit -m "godep: add $(ARG)"
As you can see you'll need to add handling for situations where there are no other arguments, or where there are more than one other argument, and of course you can't add any more targets without putting them in the filter-out list, etc.
Just... not a good way to do it IMO.
Why don't you do something like this instead:
install-%:
go get $*
godep save ./...
git add Godeps vendor
git commit -m "godep: add $*"
Then run:
make install-github.com/stretchr/testify

Answer 2

Make variables can probably do what you want:
host> cat Makefile
install:
go get $(P)
godep save ./...
git add Godeps vendor
git commit -m "godep: add $(P)"
host> make install P=github.com/stretchr/testify
But using make just for this is probably overkill. It is much more than a scripting language.