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Alex Craft
Alex Craft

Reputation: 15336

How to get function name as string in macro/template?

Can't figure out how to get function name as string in macro.

The code below should generate rlisten("multiply", multiply) but it won't compile, playground.

import macros

proc rlisten*[A, B, R](fn: string, op: proc(a: A, b: B): R): void =
  echo fn

macro remotefn(fn): void =
  quote do:
    rlisten($`fn`, `fn`) # It should generte `rlisten("multiply", multiply)`

proc multiply(a, b: int): int = discard
remotefn multiply

Upvotes: 1

Views: 321

Answers (1)

haxscramper
haxscramper

Reputation: 775

First you need to accept typed or untyped parameters to a macro. In this particular case you need to use typed argument in order to be able to access the function symbol (symbols are identifiers replaced by type resolution pass of the compiler).

import macros

proc rlisten*[A, B, R](fn: string, op: proc(a: A, b: B): R): void =
  echo fn

macro remotefn(fn: typed): void =
  echo fn.treeRepr()
  # ^ Show tree representation of the argument. In this particular case it is just a
  # single function symbol.
  let name = fn.strVal()
  echo "Function name is ", name

proc multiply(a, b: int): int = discard
remotefn multiply

Outputs

Sym "multiply"
Function name is multiply

Upvotes: 2

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