Thanks' y'all for the answer to an easy question - ri.
Now here's a sick one.
HTML Tidy is an excellent program and system (by Dave Raggett) that cleans and pretty-prints HTML. Below my sig is an assertion that uses assert_tidy to scan a @response.body, in a Rails functional test, and complain about any shenanigans in the HTML. (Take out the assert_xml call if you would like to use it without my assert_xpath plugin.)
Note that web browsers forgive shenanigans, but Rails developers should not, because the cleanest HTML code is easiest to test.
Suppose someone gave us fresh HTML to import as eRB (.rhtml). Such as from an obsolete PHP project. We ought to upgrade, cleanse, and pretty-print that HTML like this...
tidy -i -asxhtml old.html > new.rhtml
That upgrades the HTML, fixes missing and broken tags, etc.
Now suppose someone forgot to do that, and they invested their new .rhtml file with lots of <%%>, containing if statements and code-generating things.
Has anyone invented a pretty-printer that skips over the <%%> tags?
If not, I will presently report how to tidy that code by replacing <% and %> with <!--% and %-->, running tidy, and switching the tags back...