How to write function similar to `echo` in Nim?

Question

I'm trying to write wrapper for echo the code below doesn't work, playground

import sequtils, strutils, sugar

proc p*(args: varargs[typed, `$`]): void =
  echo args.map((v) => $v).join(" ")

Error:

/usercode/in.nim(3, 8) Error: invalid type: 'typed' in this context: 'proc (args: varargs[typed])' for proc

haxscramper · Accepted Answer · 2021-01-27T16:48:30.047

10

import sequtils, strutils, sugar

proc p*(args: varargs[string, `$`]): void =
  echo args.join(" ")

varargs accepts type to be converted to as first argument, so your code is almost correct, but you need to replace typed with string, and then the function call would be equivalent to p([$arg1, $arg2]) basically.

Nim by example for varargs - link

edited Jan 27 '21 at 16:48

answered Jan 15 '21 at 09:08

haxscramper

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1

You didn't mention that `echo` can accept `varargs[typed]` because it's a compiler magic. – lqdev Jan 15 '21 at 09:10
2

since conversion to string is already done by `varargs[string, $]` you can also drop the `map`. – pietroppeter Jan 15 '21 at 09:30

How to write function similar to `echo` in Nim?

1 Answers1