So the '$' is referred as 'interpolation' in Julia to form expressions. I'm passing mine into the macro, and Benchmark will produce an error depending on how you're passing a function/expression. The Julia doc covers more examples to show how it works! docs.julialang.org/en/v1/manual/metaprogramming/#man-expression-interpolation
I think you forgot to explain the '$' in the ($x) idiom.
So the '$' is referred as 'interpolation' in Julia to form expressions. I'm passing mine into the macro, and Benchmark will produce an error depending on how you're passing a function/expression. The Julia doc covers more examples to show how it works! docs.julialang.org/en/v1/manual/metaprogramming/#man-expression-interpolation