Backport Markdown from Julia 0.4.

[MichaelHatherly]

For conditionally importing the module in 0.3 I've been using

if VERSION < v"0.4-dev+1488"
    include("../deps/Markdown/src/Markdown.jl")
    import .Markdown
end

Trying to put the condition inside the Markdown module itself was giving me some trouble. Any ideas on how best to conditionally import or is this sufficient?

[MichaelHatherly]

Hold on a moment, forgot to change the REQUIRES.

[MichaelHatherly]

Should be fine now. Swapped out Lazy for Compat.

[MikeInnes]

Thanks! I don't think it's worth worrying about conditionally importing on 0.4 too much, the only ways I can think of doing it are overly messy.

[MichaelHatherly]

Thanks.

[hayd]

Probably the thing to do here is to get people to use @compat using Base.Markdown. The tricky part is: what should people put in their REQUIRES?

[MikeInnes]

Installing Markdown.jl in 0.4 is redundant but not exactly that bad – I say just put it in requires as usual.

[hayd]

I get warning messages in 0.4:

julia> using Markdown
warning: use `@compat using Markdown` to support julia 0.3+
Warning: using Markdown.Markdown in module Main conflicts with an existing identifier.

# new session
julia> @compat using Markdown
warning: use `@compat using Markdown` to support julia 0.3+
Warning: using Markdown.Markdown in module Main conflicts with an existing identifier.

I'm not sure where this message is coming from, but IMO it should say @compat using Base.Markdown, and we put something in compat to handle this.