Macro Question / Type Problem

General Usage
1 
    function instrument(f1::EvaluatorFunction, f2::TrapFunction, ex::Expr)
      # returns an expr after modifying ex 
   end
    function instrument(trap_fun::TrapFunction, ex::Expr ;amod = current_module())
        instrument(EvaluatorFunction(amod.eval),trap_fun,ex)
    end

    function instrument(eval_fun::EvaluatorFunction,ex::Expr)
        trapless = Expr(:block, :(:T{false}) , ex)
        instrument(eval_fun,TrapFunction(deftrap),trapless)
    end

  macro  instrument(fun,ex)
      esc(quote
            instrument($fun,$ex)
         end)
  end

#Example usage
@instrument eval function f(x)
 x
end

this code doesn’t work, because in the macro, ex is being passed as a function, not an Expr. is there way to pass ex as an Expr not an Function.

2

Is

  macro  instrument(fun,ex)
      esc(quote
            instrument($fun,$(QuoteNode(ex))
         end)
  end

what you want?

3

Hi,

I think what I am looking for is a way to dispatch on the macro argument fun.
I also realized the instrument should return an expr and evaluated so macro code should look something like

  macro  instrument(fun,ex)
      esc(quote
            $(instrument($fun,$(QuoteNode(ex)))
         end)
  end

But this doesn’t work either.

Thanks.

4

It’s unclear from what you discribed,

  1. When do you need instrument to execute (runtime or macro expansion time)
  2. When do you want the “eval_fun” to execute and what do you want it to do. In fact, you are likely using it incorrectly.
5
  1. the instrument call within the macro should be expanded to an expr within the macro expansion time.
  2. the argument fun in the macro can be TrapFunction or EvaluatorFunction , and I want to dispatch to correct instrument function using the type of the fun argument.
  3. eval_fun function will be executed in runtime after macro expansion. The eval function is used to executing the expr injected into the expression at runtime.
#Example usage
@instrument evaluator function f(x)
 x
end

evaluator is a EvaluatorFunction type carrying a function confirming to type signature (amod::Module,ex) like eval.

Thanks

6

Then you should just do instrument(...) or esc(instrument(...)) in the macro.

That’s impossible.

That’s likely wrong. The execution of expression at runtime shouldn’t need a “eval function”. The macro return value will be executed and wrapping it in eval is almost garantee to be wrong.

7

care to explain why?

Thanks

8

That information is not available to the macro.