FoxPro for Macintosh Language Tips and Tricks

• 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.

   _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:\

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"

   COPY FILE D:GraphicImage.PIC TO C:

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

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

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

   #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).