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4431 :: Evaluation order

• juanv (orginal) [2018-12-04T01:18:56+01:00] view original

  echo len"a" + 1  # Ok, parses as len("a") + 1
  echo ord'a' + 1  # Error, parses as ord('a' + 1)
  Run

  I think the second line must be parsed as the first one

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• Araq (orginal) [2018-12-04T16:54:42+01:00] view original

  That's not "evaluation order", that's "parsing precedences".

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• juanv (orginal) [2018-12-04T21:55:53+01:00] view original

  Sorry, I don't know how to change the wrong tittle.

  In any case, what's the rationale for this different "parsing precedence"

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• demotomohiro (orginal) [2018-12-05T06:05:06+01:00] view original

  import macros
  
  dumpTree:
    len"a" + 1
    ord'a' + 1
    ord 'a' + 1
  Run

  output:

  StmtList
    Infix
      Ident "+"
      CallStrLit
        Ident "len"
        RStrLit "a"
      IntLit 1
    Command
      Ident "ord"
      Infix
        Ident "+"
        CharLit 97
        IntLit 1
    Command
      Ident "ord"
      Infix
        Ident "+"
        CharLit 97
        IntLit 1
  Run

  len"a" is a Generalized raw string literals. 'a' is a character literal but there is no generalized character literals. https://nim-lang.github.io/Nim/manual.html#lexical-analysis-generalized-raw-string-literals

  So ord'a' + 1 is parsed as Command invocation syntax.

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• juanv (orginal) [2018-12-05T19:44:33+01:00] view original

  Perfect explanation, thank you!

  It's a pity that I can not save myself a couple of parenthesis writing ord'p' + 2. I hate unnecessary parentheses and that's why (among other things) I love the NIM language

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• SolitudeSF (orginal) [2018-12-05T20:02:03+01:00] view original

  then use 'p'.ord. what the problem?

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• juanv (orginal) [2018-12-05T22:35:20+01:00] view original

  This was just an example. There are other examples where your notation is not possible and the parentheses are mandatory:

  let someBool = true
  if "ask".startsWith'a' and someBool:
  # Error, parsed as startsWith('a' and someBool)
      echo "...."
  Run

  I think that for consistency with the string case this could be parsed as startsWith('a') and someBool

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