Package cannot be loaded in atreplinit with startup.jl or on the REPL

[caleb-allen]

So far, the standard way to load VimBindings.jl has been to do the following.

$ julia -i -e "using VimBindings"

One reason for this is that the package overwrites a large amount of REPL code, and since the REPL is initialized and then atreplinit() is called, any code overwritten is simply discarded since the world age of the VimBindings.jl code is younger than the REPL code running in a loop. More details here

This is also why a REPL user cannot simply call using VimBindings from within the REPL to "gain" new behavior.

In the course of writing this issue, I discovered that VimBindings can in fact be loaded from startup.jl—only it must be loaded outside of atreplinit, for example:

if isinteractive()
    @eval using VimBindings
end

Looking at client.jl in julia/base, it becomes clear why this is the case: REPL code is loaded, and immediately atreplinit is called (as the name suggests). Thus, trying to initialize VimBindings from within atreplinit won't affect any REPL code, because it's already been initialized.

It is blindingly obvious in hindsight that REPL code can be overwritten and modified before a call to atreplinit! But it is what it is.

Still, it may be able to be improved. The best approach would be one which can simply take the repl object and modify the object itself, rather than overwriting any stdlib code at all.