[julia-users] nested macro with `let`

[Gustavo Goretkin]

I have this macro

"""given symbols, produce a dictionary of symbol=>value"""
macro symbol_dict(symbols...)
    Dict([__x=>@eval($(__x)) for __x in symbols])
end

that works like this
julia> (x,y) = (30,50)
(30,50)

julia> @symbol_dict(x,y)
Dict{Any,Any} with 2 entries:
  :y => 50
  :x => 30

I have another macro

macro value_dict(decision_variables...)
    rebindings = [:($(_x) = value($(_x))) for _x in decision_variables]
    # print(rebindings)
    @eval let $(rebindings...)
        println($rebindings)
        println("x", x)
        println("y", y)
        D = @symbol_dict($(decision_variables...))
    end
end

which behaves like

julia> @value_dict(x,y)
[:(x = value(x)),:(y = value(y))]
x60
y100
Dict{Any,Any} with 2 entries:
  :y => 50
  :x => 30

I expected that the dictionary have the "rebound" values. What am I 
misunderstanding? I could stand to re-read many sections of the manual...

I see that if I do
julia> @value_dict(x)
[:(x = value(x))]
x60
y50
Dict{Any,Any} with 1 entry:
  :x => 30

It prints out `y50`, which I expect. `y` wasn't rebounded in the `let` 
clause, so its original value is visible to the print call. To the macro 
invocation, however, only the original values of x and y are visible.

This is Julia Version 0.4.4-pre+1.
Thanks!
Gustavo