Auto-formatter for GDL game rules

[samschreiber]

GGP Base should include a tool that automatically formats game rules in a clean, canonical way. Among other things, this should do the following:

• Put each relation on a separate line, with splitting for long lines.
• Group similar relations, and separate out important groups (role, next, legal, etc)
• Trim unnecessary whitespace.

Ideally it would preserve comments (in one form or another), but that might be more challenging.

This should not change the semantics of the game at all. One possible use-case is having this run automatically for all of the games in an online game repository.

Given two game descriptions, you should get a meaningful easy-to-read report if you auto-format both and run them through a diff tool. This will make it substantially easier to understand the differences between different versions of the same game.

[AlexLandau]

The Griddle validation library now has a "GameIndenter" that does something like this; it fixes up the whitespace "canonically", but leaves comments and the large-scale structure of the file intact.