[julia-users] How to interpolate a variable as a macro argument?

[Kaj Wiik]

I have a problem in using variables as argument for macros. Consider a 
simple macro:

macro testmacro(N)
    for i = 1:N
        println("Hello!")
    end
end

@testmacro 2

Hello!
Hello!


So, all is good. But if I use a variable as an argument,

n = 2
@testmacro n


I get an (understandable) error message "ERROR: `colon` has no method 
matching colon(::Int64, ::Symbol)".

Is this the correct place to use eval() in macros, like

macro testmacro(N)
    for i = 1:eval(N)
        println("Hello!")
    end
end

This seems to work as expected. I tried multitude of combinations of dollar 
signs, esc, quotes and brackets, none of them worked :-), got "ERROR: error 
compiling anonymous: syntax: prefix $ in non-quoted expression"...

Are there better ways to do this, is it OK to use eval() in this context?

Thanks,
Kaj