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6172 :: Generate doc comment from template?

• spip (orginal) [2020-04-08T04:29:07+02:00] view original

  Is it possible to generate doc comments from templates? I have something like:

  template foo(fn: untyped, doc: string) =
    template fn*(a: Foo) =
      "## " & doc    <======== I would like to inject doc comment here
      callfunc(fn, a)
  Run

  that is instantiated like this:

  foo(bar, "Doc comment about bar")
  Run

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• solo989 (orginal) [2020-04-08T07:14:56+02:00] view original

  You could do

  import macros
  macro setDocComment(a : static[string]) : untyped =
    result = nnkCommentStmt.newTree()
    result.strVal = a
  template foo(fn: untyped, doc: static[string]) =
    proc fn*(a: Foo) =
      setDocComment(doc)
      callfunc(fn, a)
  Run

  though it only immediately calls the macro setDoc if fn is a non generic proc

  For a template or generic proc you could instead do

  import macros
  macro foo(fn: untyped, doc: static[string]) =
    let
      docString = nnkCommentStmt.newTree()
    docString.strVal = doc
    result = quote do:
      proc `fn`*(a: Foo) =
        `docString`
        callfunc(`fn`, a)
  Run

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