[fpc-pascal] I'm working on automated Help Output for console apps

[Benito van der Zander]

Hi,

I also made such a thing:

var optionsreader: TCommandLineReader;
begin
   optionsreader := TCommandLineReader.create;

   optionsreader.declareFile('file', 'The file to be processed');
   optionsreader.addAbbreviation('f');

   optionsreader.declareFlag('help', '');
   optionsreader.addAbbreviation('h');

   optionsreader.declareFlag('version', 'Print the version of the 
application');
   optionsreader.addAbbreviation('v');

   if optionsreader.existsProperty('help') then
      writeln(optionsreader.availableOptions);

end.


Output:

--file=<file>  or -f    The file to be processed
--help or -h
--version or -v         Print the version of the application


You can download it at http://www.benibela.de/sources_en.html#rcmdline

Benito

On 20.11.20 01:33, Graeme Geldenhuys via fpc-pascal wrote:
> Hi,
>
> I'm working on a automated help output writer(s) for console apps.
> Thus no more tedious and ugly output when you do: myapp -h
>
> My aims:
>   * I write a lot of console apps, so this would be very useful to me.
>   * Ability to swap out the help formatter. It's interface based, so
>     custom implementations can easily be created.
>   * Auto align help options and descriptions - the most annoying thing to
>     do manually. ;-)
>   * Ability to define console width in which to format and wrap the help
>     output, but has a default value.
>   * The idea is loosely base on the Java version found in Apache Commons.
>
> When it's done I'll obviously shared it as open source somewhere.
>
> With that said, below is how I currently use it. It uses the Builder design
> pattern so gives it the Chain Invocations syntax. I know it's not something
> often seen in Pascal programs, but it makes it very easy to read and easy
> to use/type, especially with code completion editors like Lazarus IDE.
>
> For those console programmers out there... Is there anything in console help
> output that you like or wish you had. That way I could possibly add it and
> make this even more useful to a wider audience.
>
> I'm still working on AppName, Version and Usage output.
>
> Example code:
> ==========================
> var
>    optionlist: TOptions;
>    helpFormatter: IHelpFormatter;
>    header: string;
>    footer: string;
> begin
>    optionlist := TOptions.Create;
>
>    optionlist.add(TOption.Builder
>              .isRequired
>              .withDescription('The file to be processed')
>              .hasArg
>              .withArgName('file')
>              .withLongOpt('file')
>              .build('f'));    // build() always takes the mandatory short option.
>
>    optionlist.add(TOption.Builder
>              .withLongOpt('help')
>              .withArgName('test')  // this is ignored because .hasArg was not specified
>              .build('h'));
>
>    optionlist.add(TOption.Builder
>              .withDescription('Print the version of the application')
>              .withLongOpt('version')
>              .build('v'));
>
>    header := 'Do something useful with an input file' + LineEnding;
>    footer := LineEnding + 'Please report issues at http://example.com/issues';
>
>    helpFormatter := TBasicHelpFormatter.Create();
>
>    // sample outputs with increasing verbosity
>
>    writeln('===========================   (1)');
>    helpFormatter.printHelp(optionlist);
>
>    writeln('===========================   (2)');
>    helpFormatter.printHelp('DocView v1.0', optionlist);
>
>    writeln('===========================   (3)');
>    helpFormatter.printHelp('DocView v1.0', header, optionlist, footer);
>
>    writeln('========== the end =================');
>    optionlist.Free;
> end;
> ==========================
>
>
> And here is the example output for the 3 options so far:
>
> ===========================   (1)
> * -f,--file <FILE>    The file to be processed
>    -h,--help
>    -v,--version        Print the version of the application
>
> * indicates required parameters
> ===========================   (2)
> DocView v1.0
> * -f,--file <FILE>    The file to be processed
>    -h,--help
>    -v,--version        Print the version of the application
>
> * indicates required parameters
> ===========================   (3)
> DocView v1.0
> Do something useful with an input file
>
> * -f,--file <FILE>    The file to be processed
>    -h,--help
>    -v,--version        Print the version of the application
>
> * indicates required parameters
>
> Please report issues at http://example.com/issues
> ========== the end =================
>
>
>
> Regards,
>    Graeme
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freepascal.org/pipermail/fpc-pascal/attachments/20201120/ef3151e4/attachment.htm>