Mirror of forum.nim-lang.org

559 :: A new syntax for module imports

• JasonJAyalaP (orginal) [2014-09-16T22:57:07+02:00] view original

  The import syntax could be simplified and made both more aesthetic and memorable by getting rid of from and nil

  The two concepts involved:

  1 Control which procedures and types are imported

  • Include all
  • Include only...
  • Include all but...

  2 Control which namespace(s) are created for those procs/types

  • Use current namespace
    • Note: Is it ever a good idea to import into the current namespace?
  • Specify a new namespace
  • Use <module name> as namespace
    • Note: The default in all languages, even when a new namespace is specified(!)

  Here's the syntax for what I think is the cleanest solution. I added the keywords open and include, and I got rid of from and nil:

  import <module> [ [as <alias>] | open ] [ <include|exclude> N1,.. ]

  The first part is where we're importing from. The second part is where we import to (if not specified, module name is used as the namespace for convenience). The third part is what we're importing (if not specified, everything is imported).

  Alternatively, include could be renamed to only

  Examples:

  
  import library
  import library include my_proc
  import library exclude my_proc2
  import library as lib
  import library as lib include my_proc
  import library as lib exclude my_proc2
  import library open
  import library open exclude my_proc2
  import library open include my_proc
  Run

  Long example with alignment:

  
  import
    net
    asyncio  as ad
    base64   as b64 exclude encode
    strutils open
    os              include sleep
  Run

---

• JasonJAyalaP (orginal) [2014-09-17T01:11:54+02:00] view original

  Hrm. After talk this over in the irc room, I realize I'm making assumptions that don't hold. I'll think more about this.

---

• LeuGim (orginal) [2014-09-18T13:12:03+02:00] view original

  Note: The default in all languages, even when a new namespace is specified(!)

  In what languages? In Pascal symbols are imported in the current namespace.

  Note: Is it ever a good idea to import into the current namespace?

  Module names or aliases as namespaces arre needed for disambiguation, and nobody likes typing, so when no there's ambiguity, shorter syntax (using current namespace) is better. And Nim uses simultaneously current namespace and module name / alias, so one can just import a module and try using its symbols, and only when the compiler complains of ambiguity - add the namespace. So open should be the default, and the opposite - explicitly specified.

---