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Q117722: FoxPro for Macintosh Language Tips and Tricks

Article: Q117722
Product(s): Microsoft FoxPro
Version(s): MACINTOSH:2.5b,2.5c,3.0b
Operating System(s): 
Keyword(s): kbcode
Last Modified: 03-AUG-2000

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Visual FoxPro for Macintosh, version 3.0b 
- Microsoft FoxPro for Macintosh, versions 2.5b, 2.5c 
-------------------------------------------------------------------------------

SUMMARY
=======

The information below gives language tips and tricks for FoxPro for Macintosh.
This information is also found in FoxPro online Help in the "Language Tips"
topic under the "Tips and Tricks" topic.

MORE INFORMATION
================

Moving a Screen Object
----------------------

Use _CUROBJ to move to a particular screen object. This object can even be
itself. You might want to do this in order to change the value of an @...GET
object while in that object's VALID clause.

The following example changes the value of x without leaving the @...GET. When
you set the value of _CUROBJ, try to avoid hard-coding an actual number there
because reordering fields in the Screen Builder can cause unexpected results.

     x = some_value
     _CUROBJ = _CUROBJ
     RETURN .T.

To avoid hard-coding a value, use an expression like:

     _CUROBJ = OBJNUM(myvar)

Drives and Folders
------------------

Several FoxPro functions can be used to obtain information about drives and
folders. Compare the returned values after issuing the command SET DEFAULT TO
\FOXPRO.

        ? SYS(5)
     MacHD:
        ? SET('DEFAULT')
     MacHD:

        ? CURDIR()
     \FOXPRO\ 
        ? SYS(2003)
     \FOXPRO
        ? FULLPATH(SET('DEFA'))
     MacHD:\ 

You can also use the ADIR() function to see if a specific folder exists.

Set Volume to Shorten Paths
---------------------------

You can use SET VOLUME to ease the task of typing long Macintosh folder and path
names.

For example, assume your Macintosh hard disk is named MacHD, and the folders in
which your files are located are MacHD:PICT files and MacHD:Microsoft
FoxPro:Project One. If you issue the following commands

     SET VOLUME C TO "MacHD:Microsoft FoxPro:Project One"
     SET VOLUME D TO "MacHD:PICT files"

whenever you use a command that specifies a file in these folders, you can use
the single-letter drive or volume designation. For example

     COPY FILE D:GraphicImage.PIC TO C:

instead of

     COPY FILE MacHD:PICT files:GraphicImage.PIC ;
        TO MacHD:Microsoft FoxPro: Project One

The volume mapping can also be specified in your CONFIG.FPM configuration file.
For example, you can place the following lines in your CONFIG.FPM configuration
file:

     VOLUME C = "MacHD:\Microsoft\FoxPro"
     VOLUME D = "MacHD:\Microsoft\FoxPro\Project One"
     VOLUME E = "MacHD:\PICT files"
     DEFAULT = C:

Except for the colon following the Macintosh hard disk name, colons and
backslashes can both be used as delimiters in FoxPro for Macintosh. Note that
FoxPro for Macintosh does not recognize folder names containing embedded back
slashes (\).

For more information, see SET VOLUME.

USE Command
-----------

You can issue the command USE IN 0 to open a table in the first available work
area. This command does not select that work area in which it opened the table.
You must use the SELECT command to do this. You can issue the command USE IN
<alias> to close a table without selecting its work area.

The SHARE clause for the USE command allows you to open a table for shared use
without using the SET EXCLUSIVE command. For more information about the USE
command, refer to the USE topic.

Cross-Tab Output to Spreadsheets
--------------------------------

Run the GENXTAB program to create cross-tabulated output that you can COPY TO or
EXPORT to a spreadsheet.

Custom Messages
---------------

You can display custom messages in the FoxPro status bar. To do this, SET TALK
OFF then use the SET MESSAGE TO <expC> command to specify a message. (You
can pass a null string to display nothing.) SET MESSAGE TO without a parameter
will restore the status bar to its normal functionality.

Preprocessor Directives
-----------------------

Do not use _WINDOWS, _DOS, _MAC, or _UNIX with preprocessor directives (that is,
#IF ... #ENDIF). These are designed to be runtime variables. For example the
following will not work:

     #define _DOS .t.
     #define _MAC .f.
     * For code compile in MS-DOS, the following would not work:
     DO CASE
       CASE _DOS
         ? "Running in MS-DOS"
       CASE _MAC
         ? "Running on Macintosh"
     ENDCASE

This code would not work because _DOS would be changed to .T. and _MAC would be
changed to .F. so that the code could never work properly again. Instead use the
following:

     #if "Win" $ VERS()
     #define WINDOWS_CODE .t.
     #elif "Mac" $ VERS()
     #define MAC_CODE .t.
     #elif "Unix" $ VERS()
     #define UNIX_CODE .t.
     #else
     #define DOS_CODE .t.
     #endif
     #if WINDOWS_CODE
     ? "Compiled under WINDOWS"
     #elif DOS_CODE
     ? "Compiled under DOS"
     #endif

Prevent Preprocessor Substitution in Text Strings
-------------------------------------------------

#DEFINE prevents preprocessor substitution in text strings. Note that square
brackets [ ] can be used do delimit text strings. This means that no
substitution will be made in the following:

     #DEFINE nosub 1
     DECLARE an_array(3)
     *** This will cause a 'variable NOSUB not found' error
     *** because no substitution was made
     ? afunc[an_array[nosub]]
     FUNCTION afunc
     PARAMETER x
     RETURN x

Development Tools
-----------------

The FOXTOOLS.MLB file, which is located in your Systems:Extensions folder,
contains a variety of functions that you can use to enhance your applications.
Many of these functions provide access to API routines and Macintosh functions.
You can view these using the DISPLAY STATUS command (after you issue SET LIBRARY
TO foxtools).

Additional query words: vFoxMac FoxMac on-line foxhelp.dbf foxhelp.hlp akz

======================================================================
Keywords          : kbcode 
Technology        : kbHWMAC kbOSMAC kbVFPsearch kbAudDeveloper kbFoxproSearch kbFoxPro250bMac kbFoxPro250cMac kbVFP300bMac
Version           : MACINTOSH:2.5b,2.5c,3.0b

=============================================================================

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