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11558 :: cannot evaluate at compile time

• anter003 (orginal) [2024-05-06T14:38:52+02:00] view original

  
  proc parseStringSeq*(text: string, charset: CHARSET): CHARSEQ =
      var osq: CHARSEQ = @[]
      for i in countup(0, text.len - 1):
          if text[i].isAlphaAscii():
              osq.add(charset[int(text[i]) - 63]) #alphabets(capital)
          elif text[i].isDigit():
              osq.add(charset[int(text[i]) - 2]) #digits
          else:
              discard
      return osq
  Run

  This is a shoddy proc for taking a string and converting into other type char by char. And when I try to run it it says cannot evaluate at compile time: text. If i replace string with static[string], it says cannot evaluate at compile time: i.

  I have a hard time understanding why this error happens.

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• Calonger (orginal) [2024-05-06T14:47:45+02:00] view original

  CHARSET is tuple type ? --> index must compiletime , array / seq will fix

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• anter003 (orginal) [2024-05-06T15:20:23+02:00] view original

  doesn't tuple also support numeric index?

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• SolitudeSF (orginal) [2024-05-06T15:43:32+02:00] view original

  index has to be known at compile-time. nim is statically typed, you cant have a value have different type based on runtime condition.

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• dwhall256 (orginal) [2024-05-06T15:52:38+02:00] view original

  Here's what I think you are trying to do. Notice I replaced osq with the implicit variable result.

  https://play.nim-lang.org/#pasty=YsYZAnvPfXPY

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• sls1005 (orginal) [2024-05-06T18:30:23+02:00] view original

  When you evaluate an expression at the compile-time, all the operands have to be compile-time expressions (mostly literals, constants and expressions consisted of them) in that context.

  When you write

  "123"
  Run

  Then "123" can be used as a compile-time expression.

  When you write

  const text = "123"
  Run

  Then text can be used as a compile-time expression.

  However, when you write

  var text = "123"
  Run

  text cannot be used as a compile-time expression, because it is considered a runtime variable (var). The same applies to let-variables.

  When you write

  static:
    var text = "123" & "4"
    text
  Run

  This whole static-expression is a compile-time expression once resolved. But within the context of this inner block, text is still not considered static.

  Complex. I know. Just think of it as stack-like.

  Also it seems that the lengths of arrays are always considered static, while that of string/seq are not (and thus as static as the associated variable).

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