Align option names and syntax with asciidoctor command

[mojavelinux]

I'd like to align the option names that go in additionalparam with the asciidoctor command.

I'm proposing the following changes.

1. Prefer double dash (--) instead of single dash (-) prefix for long option names
2. Use names from the asciidoctor command when there's a matching option
3. Use the same parsing logic for the attribute string (or allow attributes to be specified using multiple -a options)

The mapping would be as follows:

• -include-basedir => --base-dir or -B
• -d => --destination-dir or -D
• -stylesheetsfile => --stylesheet (file is assumed)
• -attributes => --attributes

We want to reenforce knowledge of AsciiDoc option across the ecosystem.

[mojavelinux]

Here's the logic that should be used for parsing the attribute string:

https://github.com/asciidoctor/asciidoctor-gradle-plugin/blob/master/src/main/groovy/org/asciidoctor/gradle/AsciidoctorTask.groovy#L278

[mojavelinux]

Eventually, I want to make attribute parsing a public API in AsciidoctorJ (and subsequently, Asciidoctor).

[mojavelinux]

I also like processorArgs or argLine instead of additionalparam for the name of the configuration property.

[mojavelinux]

I'm okay with additionalProcessorArgs too.

[mojavelinux]

On further thought, perhaps it's better for the attributes to support a collection called attributes to be consistent with the Maven plugin. See this example: https://github.com/mojavelinux/asciidoctor-maven-plugin-example/blob/master/pom.xml#L111

[mojavelinux]

In general, I think we should try to align with the Maven plugin where possible since, again, it reenforces knowledge. There's a very good chance users will be configuring both plugins in the same project.

[mojavelinux]

Where alignment is not possible due to restrictions in how the tool is configured, I understand.

[mojavelinux]

I now see that Doclet uses the convention of single hyphen prefixes (order me a beer and I could do a rant about engineers at a Unix company not following the posix conventions...argh).

I think for options that clearly map to Asciidoctor options, we should use the double hyphen. However, I realize that we might not be able to do anything about the -d flag. Water over the damn.

[johncarl81]

+1 for consolidating/defining parameters and their appropriate argument names in a common library like Asciidoctorj.