Question about Lex

[G.COTSONAS]

I cannot seem to get Lex to match tokens beginning
with an at-sign; am I missing something?
I have tried quoting it, and using a backslash for escape,
but something gets lost in the translation.
Depending upon other rules in the specification,
sometimes the at-signs are untouched,
and sometimes no output stream is generated at all;
no Lex buffer overflow under any circumstances.

George Cotsonas
AT&T ISL