Documentation for Psych to_yaml options?

Question

Ruby 1.9.3 defaults to using Psych for YAML. While the ruby-doc documentation for it is completely lacking, I was able to find one external piece of documentation

Answer 1

Deep in the guts of ruby-1.9.3-p125/ext/psych/emitter.c I found three options:

• indentation - The level must be less than 10 and greater than 1.
• line_width - Set the preferred line width.
• canonical - Set the output style to canonical, or not (true/false).

And they work!