VimL Parser (GitHub: ynkdir / vim-vimlparser) by Yukihiro Nakadaira is a Vim Script parser that, given a suitable file, will output a parenthesized Polish prefix notation version of the script. For example,
call vimlparser#test('.vimrc') will display a parsed version of your Vim configuration.
The project also includes tests, with examples of the expected output. The source in this plugin is pretty huge, so you might like to check it out if you want to see something extreme in Vim Script.
It basically provides a quick way to drop into pry from Vim, but can also do things like yank the last line from pry's history.