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2419 :: get the most local symbol from `bindSym`

• jxy (orginal) [2016-07-28T19:55:39+02:00] view original

  bindSym always returns all the symbols, local and larger scopes, for a variable. If I have

  import macros
  var a = 0
  block:
    var a = "block"
    macro m: stmt =
      let s = bindsym"a"
      echo s.lisprepr
      result = newstmtlist()
    m()
  Run

  I get

  
  ClosedSymChoice(Sym(a), Sym(a))
  Run

  How do I know which one is the actual local symbol, and which are shadowed?

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• Araq (orginal) [2016-07-28T21:02:10+02:00] view original

  First (at index 0) position is the most local one. I think.

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• jxy (orginal) [2016-07-28T21:30:19+02:00] view original

  Ok. With the following code

  import macros
  var a = 0
  block:
    var a = "block"
    block:
      var a = true
      block:
        var a = 0.0
        macro m: stmt =
          let s = bindsym"a"
          for n in s: echo n.gettypeinst.lisprepr
          result = newstmtlist()
        m()
  Run

  I got

  
  Sym(float64)
  Sym(bool)
  Sym(string)
  Sym(int)
  Run

  I guess it depends on how you implemented the symbol lookup. Is it guaranteed that the first one is the most local one?

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• Araq (orginal) [2016-07-28T21:54:31+02:00] view original

  Yes and please create a PR that documents this behaviour. And add your snippet as a test case.

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• jxy (orginal) [2016-08-18T18:27:13+02:00] view original

  How do you write a test case for macros or compile time proc? Where should I add it?

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• jlp765 (orginal) [2016-08-18T23:34:32+02:00] view original

  tests/<testtype>/<testfile.nim>

  and the test file should start with the letter "t",

  eg tests/macros/tbindsym2.nim

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• OderWat (orginal) [2016-08-19T19:30:23+02:00] view original

  Maybe @jxy is asking about how to test something which happens on compile time and therefor has no output when run but when compiled.

  You could do it like this:

  # test bindsym order
  import macros
  
  template check(x, y) =
    doAssert(x.gettypeinst.lisprepr == y)
  
  var a = 0
  block:
    var a = "block"
    block:
      var a = true
      block:
        var a = 0.0
        macro m: untyped =
          let s = bindsym"a"
          check(s[0], "Sym(float64)")
          check(s[1], "Sym(bool)")
          check(s[2], "Sym(string)")
          check(s[3], "Sym(int)")
          result = newstmtlist()
        m()
  Run

  Not sure if there is a better way though.

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• jxy (orginal) [2016-08-23T20:08:24+02:00] view original

  That was the first question. Thanks. I guess the idea is that if anything breaks it shouldn't compile. I'm going to learn how to do PR on github.

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