[TYPO3-english] Using vertical bars in regular expressions in Typo forms

[Jonathan Hartshorn]

Is it possible to use the '|' metacharacter in EREG expressions in mailforms?

I have been trying to do this, but when I enter the raw vertical bar
it is parsed as typoscript, and when I tried %7C code the % gets url
encoded.

I have rewritten the expression without the alternative patterns, but
the result isn't quite the pattern I wanted.

BTW if an 'escape character' for typoscript is documented somewhere
please point me to it; I have been googling for quite a while to no
avail.