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The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

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     Example 1
 
     The _pwbclosefile predefined macro uses the prompt directive to
     restore the 'File has changed! Save Changes?' prompt displayed by
     the Closefile function.
 
          _pwbclosefile := cancel closefile <
 
     Closefile normally displays this prompt when the current file is
     modified and Autosave is turned off. However, when executed from a
     macro, Closefile assumes the Yes response.
 
     Example 2
 
     The GetMac macro in the following definition uses the prompt
     directive and a conditional jump to validate a filename passed to
     the Setfile function. GetMac assumes a text argument with the base
     name of a .MAC file to be found in the INIT directory.
 
          ;GetMac - Load a file of macros or assignments.
          ;
          ;Usage: Arg 'file' getMac where <file> is the base name of
          ;       a file in the INIT directory
          ;
          GetMac := cancel lasttext begline "$INIT:" endline ".MAC"  \
                    setfile <n +>Ok   lasttext begline               \
                    "Can't find \"" endline "\"" message =>          \
               :>Ok begfile arg endfile assign ->  arg refresh
 
     To validate the filename, GetMac changes the default response for
     the Setfile 'File does not exist! Create?' prompt from Yes to No so
     that the file is not created. The exact phrase in the macro is:
 
          Setfile <n +>ok
 
     The '<n' changes the default Setfile response from Yes to No. The
     '->ok' jumps to the label 'ok' when Setfile returns true (the file
     exists). Otherwise, GetMac displays a message that the file could
     not be found and exits the macro with '=>'.
 
     The 'ok' branch selects the contents of the file and executes the
     Assign function. If the assignment succeeds, GetMac closes the
     file. Otherwise, it exits the macro so that you can correct the
     assignment that caused Assign to fail.
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