Style Guidelines for CONTRIBUTING.md about j2objc-gradle

[advayDev1]

Here's the standard Groovy style guide:
http://www.groovy-lang.org/style-guide.html

Since we are a 100% groovy project, I think we should stick as closely as we can to them. A mixed Java/Groovy style I think will be even more confusing.

[brunobowden]

Looks good, we should follow this and then add extra stuff specific to Gradle. I'll work on that.

[advayDev1]

Ah good point.

[advayDev1]

Suggest we say that our style is Groovy style guide, and where it does not specify and does not conflict, back-off to Google Java style guide:
https://google-styleguide.googlecode.com/svn/trunk/javaguide.html

Also, we need to make a decision on top-level method calls in statements. We are very inconsistent between java.call(arg) style and groovy.call arg style.

[brunobowden]

I personally prefer parentheses as I find it more familiar. It sounds like the Groovy Style Guide isn't clear on this but I suspect it would make it easier for other engineers contributing.

What's your thoughts on this @advayDev1?

[advayDev1]

I'm torn. I'm huge on consistency so that style things become more mechanical and less subject to reviewer dispute. If we're going to split into parens and no-parnes, I'd suggest the following rules:

1. If the statement is solely a DSL/property setting method (ex. 'translateArgs in j2objcConfig'), do not use parentheses on the top-level method.
2. If the statement is a logging method of the form logger.LEVEL or log.LEVEL, do not use parentheses on the top-level method.
3. Otherwise, always use parentheses.

Thoughts?