Template issue with try

[gryphis]

Hi
I learned something from #19576 but run into a next issue while trying to provide a template for typed string conversion. Tree versions constructive on each other work fine if coded as procs but fail as templates, the shortest complete runable example attached:

template getTyped[T](val: string, parseType: proc (str: string): T): Option[T] =
  return (try: some(parseType(val)) except: none(typeof T))

works well as proc:

proc     getTyped(val: string, parseType: proc (str: string): int): Option[int] =
  return (try: some(parseType(val)) except: none(int))

is called as:

proc getint*(key: string): Option[int] =
  let found = getval(key)
  if found.isSome: return getTyped(found.get, parseInt)
  else: return none(int)

Using: nim 1.6.4

Thanks for help!
Andi
nimq1.zip

[ghost]

Templates are code substitution, so if you have return in a template it'll get inserted as a return where the template was "called", so in the end you would get return return (try: some(parseType(val)) except: none(typeof T)).

This is not a Nim bug, and the fix would be to remove return from your template.

[gryphis]

Thanks for quick help, it works now! Andi Am 03.03.2022 20:11 schrieb Danil Yarantsev:

Templates are code substitution, so if you have return in a template it'll get inserted as a return where the template was "called", so in the end you would get return return (try: some(parseType(val)) except: none(typeof T)). -- Reply to this email directly, view it on GitHub [1], or unsubscribe [2]. Triage notifications on the go with GitHub Mobile for iOS [3] or Android [4]. You are receiving this because you authored the thread.Message ID: ***@***.***>

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[ghost]

I assume that I can close this issue then :)