override the interpreter's parser?

[Sean McIlroy]

hi all

i'd like to write a module that, when run in the interpreter, would
cause the interpreter to read certain strings that would normally be
rejected as syntax errors (strings beginning with the @ symbol, say)
and pass them on to an object defined in the aforementioned module.
where should i look to start finding out how to do this? thanks for
any help.

peace
stm