Raymond Hettinger wrote:
"""Placeholders must be a valid Python identifier (containing only ASCII alphanumeric characters and an underscore). If an unbraced identifier ends with a non-ASCII alphanumeric character, such as the latin letter n with tilde in $mañana, then a ValueError is raised for the specious identifier.
so why keep the python identifier limitation? the RE engine you're using to parse the template has a concept of "alphanumeric character". just define the placeholder syntax as "one or more alphanumeric characters or under- scores" (\w+), use re.UNICODE if the template is created from a unicode string, and you're done. this doesn't mean that people *have* to use non-ASCII characters, of course. but if they do, things just work. </F>