I was thinking along similar lines, I've been testing out things in this branch https://github.com/jkrumbiegel/Chain.jl/tree/function-chain

Your proposed syntax doesn't work, you can always test such things by prefacing the code with Meta.@dump which will give you the syntax tree (if it's parseable, which this is not) even if nothing in it corresponds to real variables and functions.

The do syntax needs a call-like object before it (with parentheses) so I thought about this:

@chain "a|x\nb| y z " begin
    strip
    split("\n")
    @chain map() do
        split("|")
        @chain map() do 
            strip
            split
        end
    end
end

This would then work for arbitrary functions like filter, etc, that take a closure as the first argument which itself expects one argument.

I even thought about transforming any do syntax without a closure argument, even without @chain in front, but that's probably a step too far.

That looks really good. I'd be more than happy to test it over the next few days.

I even thought about transforming any do syntax without a closure argument, even without @chain in front, but that's probably a step too far.

Your sense is obv better than mine — but I don't think it'd be possible to have ambiguity, given that map() do \n isn't otherwise valid. Someone could write map() do x \n if they wanted the standard do syntax. (But OTOH I guess easier to expand than retract later...)

Yes for map that's true, but I'd want it to work for any function that takes a closure, and some don't have any args and that would probably be a really confusing edge case if such functions started to error.