On Thu, 2019-12-26 at 21:24 +0100, Jouke Witteveen wrote: > > Your proposal has the potential to create variables that would have > > scope local to a single invocation of a user-defined function, but it > > wouldn't provide scoping to Make-proper. For that reason alone, I > > would suggest narrowing down the naming of the feature. Perhaps > > something like: > > What other meaning of 'scoping to Make-proper' do you have in mind? I > fail to see a scoping scenario that is not covered by my $(let) > proposal.
I believe thutt is thinking of creating new scopes in makefiles themselves, not within a variable/function context, for example within included makefiles or even within subsections of a particular makefile. For example something where you could say: FOO = bar push scope local FOO = baz $(FOO): blah pop scope $(FOO): yuck Of course if you wanted to write a bunch of define/endif stuff and use eval you could use $(let ...) to do something like this but it can get pretty gross. That is a separate feature that wouldn't help you do what you want to do, but that's probably why thutt suggests finding a more specific term. In Lisp, "let" creates "local bindings" not a new scope. I'm not sure if that is more or less clear for people not familiar with Lisp. Here's another question: will this "do what you expect" if you invoke an include within an eval within a let? For example: $(let FOO BAR,,$(eval include myfile.mk)) will ensure that any "global" settings of FOO or BAR that are made inside of myfile.mk are forgotten about afterwards? What other sorts of tricks or issues could we get into using eval within let, I wonder...
