April 2008

Clarion Folk Lore #3 is live!

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URLs

• Top Blog Post:
  • Negative Criticism post – http://tymesaid.com/negative-critisism-comes-in-all-forms-deal-with-it
• Top Web Site:
  • Viget, Design blog – http://www.viget.com/inspire/
• News:
  • NetTalkCentral  – http://www.nettalkcentral.com
• Outside The Blue Triangle:
  • Google Application Engine – http://code.google.com/appengine/
  • Team Viewer – http://www.teamviewer.com

Answers

1. What does MEMBER() do vs. MEMBER(‘MyApp.clw’)

   Every module needs to either have a PROGRAM statement or a MEMBER statement.

   The main module of an EXE/DLL/LIB will have the PROGRAM statement. All others will have a MEMBER statement of some form.

   - The form, MEMBER(‘MyApp.CLW’) tells the module to use the global scope of MyApp.CLW

   - The form, MEMBER() has no shared scope what so ever. This form is useful for generic code, these days typically for CLASSes

2. What is the purpose of having a MAP, when it has no procedures in it?

   A MAP is used to declare prototypes for procedure. However an empty MAP isn’t quite as empty as it seems.

   Every MAP brings in %cwroot%\\libsrc\\BUILTINS.CLW
      so

      MAP
      END

      becomes

      MAP
        INCLUDE(‘BUILTINS.CLW’),ONCE
      END

   Other files that are brought in:
      – EQUATES.CLW  (found in %cwroot%\\libsrc)
      – Win32.LIB    (found in %cwroot%\\lib)

3. How do you make a QUEUE of QUEUEs ?

   You’ll need to use ,TYPEd Queues, and you’ll (typically) use NEW / DISPOSE .

      At it’s core:
      qtChild QUEUE,TYPE
      Name           STRING(42)
                      END

      ParentQ  QUEUE
      ID                  LONG
      Children     &qtChild
                          END

      Here a field of the ParentQ is a reference to another queue. Typically as you’re doing the ADD()s to the parent, you’ll either:
      a) ParentQ.Children &= NULL
      b) ParentQ.Children &= NEW qtChild  !instantiate a new one
      c) ParentQ.Children &= SomeChildQ   !already instantiated

      Remember when you’ve used NEW to instantiate, you are responsible for the matching DISPOSE, so typically when you’re doing DELETE(ParentQ) or wish to FREE(ParentQ) you will want to first DISPOSE(ParentQ.Children).

      qtFolder QUEUE,TYPE
      Name       STRING(FILE:MaxFileName)
      Path       STRING(FILE:MaxFilePath)
      ShortName  STRING(13)
      Date       LONG
      Time       LONG
      Size       LONG
      Attrib     BYTE
      SubFolders &qtFolder
               END

Above is an example of a structure for a queue of queues, where the child queue is of the same structure as the parent queue.

These sorts of structures lend themselves to recursive coding, however it’s not required.

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