Generate functions inside a function from string

[Chong_Wang]

I created a separate thread here summarizing generally what I want:

How do I create a function from an expression

Suppose I have expr = :(sin(x)+cos(x)) How can I get a function looking like x->sin(x)+cos(x) I have tried to write such a macro macro expr2fn(expr, arg) return :($arg -> $(expr)) end but it does not work julia> f = @expr2fn expr x (::#63) (generic function with 1 method) julia> f(1.0) :(sin(x) + cos(x)) Not sure what is happening here.