Problem with open files

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Fri, 04/22/2016 - 01:51 pm

Hello, so I run into a problem with open files, and wish someone could help me out. Thanks in advance.

So I have a bunch of folders (say, folder0, folder1, etc), in each folder there're a bunch of files (say file0, file1, etc). Here's a procedure that tries to load files in the folder specified by the user:
Function BatchLoad()
  String/G WorkingPath
  String RF
  Variable i, j
  GetFileFolderInfo/D/Q
  If (V_isFolder==1)
     WorkingPath = S_Path
     Newpath/O/Q SmbPth_WorkingPath, WorkingPath
  Endif
  // Do a bunch of things
  j = 0
  String FileList = IndexedFile(SmbPth_WorkingPath, -1, "????")
  Make/O/N=(0)/T FileList_dump
  For (i=0; i<ItemsInList(FileList); i+=1)
         If (StrSearch(StringFromList(i, FileList), "dump", 0) != -1)
            Redimension/N=(1 + DimSize(FileList_dump,0)) FileList_dump
            FileList_dump[j] = StringFromList(i, FileList)
            Load_dump(j, RF)
            j = j + 1
         Endif
  Endfor
End


And here's the procedure to load individual file:
Function Load_dump(FileIndex, RF)
  Variable FileIndex
  String RF
  Wave/T FileList_dump
  String FileName = FileList_dump[FileIndex]
  Variable numRef, LineIndex, j
  String FileContent
  String/G WorkingPath
  Open/R/P=WorkingPath numRef as FileName
 
  // Do a bunch of things

End


As I mentioned, I have a bunch of folders: folder0, folder1, etc. Everything worked perfectly well for folder0, but when i run BatchLoad() and specify to work on folder1 and other folders, it seems the Load_dump(FileIndex, RF) cannot correctly open files. Hope someone could take a look at and help me out. Thank you very much!
Have you stepped through this with the debugger? Where does it fail and what is the message?

--
J. J. Weimer
Chemistry / Chemical & Materials Engineering, UAH

April 25, 2016 at 05:20 am - Permalink

For starters, this does not make sense:
String/G WorkingPath
Open/R/P=WorkingPath numRef as FileName


This is identical to the same code with the first line removed. The second line uses a symbolic path named WorkingPath. This is correct if that is the name of the symbolic path. In that case, you don't need the String/G line. If, on the other hand, you have a string variable named WorkingPath that contains the name of the symbolic path, then you must use /P=$WorkingPath.

Execute this:
DisplayHelpTopic "Converting a String into a Reference Using $"


More generally, you are using global variables too much. With rare exceptions, global variables should not be used to pass information from one function to another. Using global variables for this purpose makes it difficult to understand and test code because it introduces non-obvious dependencies. You should use parameters instead. Global variables should be used primarily when you need to remember something between invocations of functions.

Rewrite your Load_dump function to use NO global variables. Whatever information it needs must be passed to it via parameters. Once you have done that, it will be easy to test Load_dump by itself, by executing a command from the command line. This will allow you to confirm that it works correctly or fix it without having to worry about the correctness of the calling function.

Once you have Load_dump working by itself, you should rewrite BatchLoad to use rely on parameters rather than global variables as much as possible. Once you have done that, you can test BatchLoad from the command line, knowing that you have already verified Load_dump.

If, having done that, it still does not work, use the debugger to debug it. Execute this:
DisplayHelpTopic "The Debugger"

April 25, 2016 at 08:17 am - Permalink