string decodeattrib(string str)
Houdini geometry attributes and group names are only allowed to contain
letters, numbers, and underscores, and must not begin with a number. Arbitrary
strings can be passed through the
encodeattrib function to generate a string
that obeys these restriction. This function takes one of these encoded
strings, and returns the original string. A string that has not been encoded
will be returned unmodified.