[erlang-questions] Makefile detecting / downloading rebar

[Gleb Peregud]

On Sun, Jul 22, 2012 at 2:17 PM, Michael Santos
<michael.santos@REDACTED> wrote:
> You could download rebar using erlang rather than wget:
>
> # shell is GNU makefile only syntax
> REBAR=$(shell which rebar || echo ./rebar)
>
> ./rebar:
>     erl -noshell -s inets start -s ssl start \
>         -eval 'httpc:request(get, {"https://github.com/downloads/basho/rebar/rebar", []}, [], [{stream, "./rebar"}])' \
>         -s inets stop -s init stop
>     chmod +x ./rebar

I have written an reasonably short curl-or-wget downloading script but
approach using Erlang seems the nicest out of all of them. Erlang has
to be present, so download will work. And it is nicer than my initial
approach, since it doesn't do links. I'll borrow this approach :)

My curl-or-wget script looks like this:

REBAR_URL=http://cloud.github.com/downloads/basho/rebar/rebar
DOWN=$(shell (which wget && echo -O rebar) || (which curl && echo -o
rebar)) # detect curl or wget

rebar:
	@which rebar && ln -sf `which rebar` || true >/dev/null 2>&1
	@test -x ./rebar || ($(DOWN) $(REBAR_URL) >/dev/null 2>&1 && chmod u+x rebar)