Only 3 real C++ parsers

Front end: the thing which takes a high-level language (e.g. C++) and
yields a language-independent, relatively machine-independent
representation for optimization and translation into machine-dependent
form. (In recent versions of GCC, this intermediate representation is
GIMPLE).

(There is no formal name for this machine-independent part that I know of,
but I've always heard it referred to as the 'middle-end'. A thousand
toplogists may scream in pain but language doesn't need to make
sense. :) )