PPWIZARD is a free preprocessor for HTML, REXX, Visual Basic or any text files.

Switch /Syntax:Spec

This is a PPWIZARD command line switch. You can set up your own default switches in the "PPWIZARD_OPTIONS" environment variable or in project files.

For some output extensions or file types PPWIZARD automatically checks the syntax of the generated files. You can turn this off, on, or tweek the output using this switch.

The syntax checking typically works by executing code which returns a specific return code if a certain 'unusual' parameter is passed. REXX, VBS and some other languages go through a loading step where syntax is validated, if this fails the code will never get executed. This is why we add a little stub to return a specific return code. The stub does not get in the way because if is never accidently invoked.

If you use this switch you will probably want to also use "/DeleteOnError:NO", so you can examine the code if an error is detected.

The first and last characters of the "Spec" defines the delimiter being used to delimit the following values:

1. Extension
   The extension (without a dot) that you are modifying the header for. Specify this in UPPER case unless the case is significant (as it would be in Unix). You can also use "*" to apply this rule to all files that don't have a specific rule (only checked if no match by extension).

   Note that currently rexx code gets checked by an alternative method, there is also no mechanism to turn off on the #output command.

2. The Test Command
   This is the command line of the command required to test the syntax of the generated program. Use "{?}" to indicate where the filename should be placed. Pass "" to disable checking.

3. The Expected Return Code
   This is the expected return code from the above command. Typically the lines you insert (see below) will return this value. Pass "" to disable checking.

4. One or More lines
   The 'Spec' delimiter can be used to split this into multiple lines. This is the line or lines of code which is inserted into the header of the file to allow the syntax checking to take place.

Use of Header File

If the test command value starts with '@' and there is no return code or lines then this indicates that a file should be read to create the stub code and set the command and expected return code values.

If your header file included conditional generation of the header based on the extension of the output file then it could make sense to use a "*" rule.

You header should output the syntax checking stub and should also set these rexx variables:

• OutSyntaxCmd
  This is the command line to be executed which invokes the file is a manner that should exercise the sub you inserted to return a specific return code. It is also possible that no stub is required and a validation program exists and you wish to call this.

• OutSyntaxRc
  This is the return code you expect your command (usually stub) to return. You are generally relying on the loading process to fail on syntax error and therefore return some other return code.

• OutSyntaxMsg
  This optional value allows you to alter the generated error message. If the message starts with '-' then the text replaces the normal error text otherwise it is additional to the normal message.

Examples

The following shows how syntax checking for files with the extension ".VBS" can be turned off:

    /syntax:~/VBS/~
    

The following shows how a file can be included to add syntax checking code for multiple extensions (first removes existing VBS code):

    /syntax:~/VBS/~ /syntax:~/*/@c:\tmp\syntax.h~
    

The following is an example of what the "hyntax.h" file could look like:

    ;--- Determine what we wish to do -------------------------------------------
    #NextId
    #info 'in syntax.h'
    #DefineRexx ''
       ;---- Get extension (if not unix then make upper case) -------------------
       @@Extn = _filespec('EXTN', '<?OutputFile>');
       #if ['<?OpSys>' <> 'UNIX']
           @@Extn = translate(@@Extn);    ;;Make upper case
       #endif
    
       ;---- Want a comment? ---
       select
           ;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
           when @@EXTN = "VBS" then
           ;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
           do
               ;--- VB SCRIPT ---
               @@Code       = 'if Wscript.Arguments.Count = 1 then if Wscript.Arguments(0) = "!CheckSyntax!" then wscript.quit(21924)';
               OutSyntaxRc  = '21924';
               OutSyntaxCmd = 'cscript.exe "{?}" //NOLOGO !CheckSyntax!'
               OutSyntaxMsg = "Note that you must not use VBSCRIPT's OPTION command without modifying or disabling the syntax checking code!";
           end;
           ;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
           otherwise
           ;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
           do
               ;--- Don't want any syntax checking code ---
               @@Code       = '';
    
               ;--- Return reserved variables with "empty" values ---
               OutSyntaxRc  = '';
               OutSyntaxCmd = '';
               OutSyntaxMsg = '';
           end;
       end
    #DefineRexx
    
    ;--- Any syntax checking code to generate? ---------------------------------*/
    #if [@@Code <> '']
        ;--- This code returns a specific return code when passed specific parameter ---
        <??@@Code>
    #endif
    

If you add any extensions (Perl etc) please consider sending them to me so I can update the documentation fo others.

PPWIZARD Manual

Thursday January 17 2002 at 6:27pm