Microsoft Office 2000/Visual Basic Programmer's Guide

Indentation

You indent code and comments within a procedure by using a two- to four-space tab stop. (The Visual Basic Editor uses a four-space tab stop by default.) Like white space, indents are used to organize code logically and make it visually appealing. The benefits from this simple technique are substantial. To see VBA and VBScript examples that do not use the general formatting techniques discussed here, take a look at the VBA examples in the modBadCodeFormatting module in FormattingExamples.doc and the script example in ScriptBadFormatting.htm in the ODETools\V9\Samples\OPG\Samples\CH03 subfolder on the Office 2000 Developer CD-ROM. To see examples that do use the formatting techniques recommended here, see the rest of the sample code in this book.

The following list contains some general guidelines regarding where, when, and how to correctly use indentation to make your code more readable and maintainable:

• Indent all code and comments within a procedure at least one tab stop. The only code lines that are not indented are the beginning and ending of the procedure and line labels used in connection with your error handler.
  
  
• If you use line breaks to format a procedure's argument list, use tabs to indent the arguments and their data-type declarations so that they are aligned with the first argument in the list.
  
  
• Indent declared variables one tab stop. Declare only one variable on a line. Indent each variable's data-type specifier so that the variable data types are aligned.
  
  
• Indent control structures at least one tab stop. If one control structure is embedded within another, indent the embedded structure one tab stop. Indent code within a control structure one additional tab stop.
  
  
• If you use a line-continuation character to break a line of code, indent the new line one extra tab stop. This creates a visual cue that the two (or more) lines belong together. If the line following the continued line is indented as much as the continued line would be, add one more tab to the continued line to distinguish it from the next line.
  
  
• Indent comments to the same level as the code the comment refers to.

Take a look at how these general techniques are applied in the following procedure:

Function GetFileList(strDirPath As String, _
                     Optional strFileSpec As String = "*.*", _
                     Optional strDelim As String = ",") As String
   
   ' This procedure returns a delimited list of files from the
   ' strDirPath directory that match the strFileSpec argument.
   ' The default delimiter character is a comma. By default, the
   ' procedure returns all files ("*.*") from the designated
   ' directory.
      
   Dim strFileList      As String ' Used to collect the file list.
   Dim strFileNames   As String ' The full path and criteria to search for.
   Dim strTemp         As String ' Temporarily holds the matching file name.
   
   ' Make sure that strDirPath ends in a "\" character.
   If Right$(strDirPath, 1) <> "\" Then
      strDirPath = strDirPath & "\"
   End If
   
   ' This will be our file search criteria.
   strFileNames = strDirPath & strFileSpec
   
   ' Create a list of matching files delimited by the
   ' strDelim character.
   strTemp = Dir$(strFileNames)
   Do While Len(strTemp) <> 0
      strFileList = strFileList & strTemp & strDelim
      strTemp = Dir$()
   Loop
   
   If Len(strFileList) > 1 Then
      ' If there are matching files, remove the delimiter
      ' character from the end of the list.
      GetFileList = Left(strFileList, Len(strFileList) - 1)
   Else
      GetFileList = ""
   End If
End Function

The GetFileList procedure is available in the modAdditionalSamples module in FormattingExamples.doc in the ODETools\V9\Samples\OPG\Samples\CH03 subfolder on the Office 2000 Developer CD-ROM.