$ perl -Mstrict -Mwarnings -E '
for (qw{!defined(FLOAT_CODE) defined(FIXED_CODE)}) {
    m{ \A ( [!]? ) defined [(] ( .*? ) [)] \z }x;
    say $1 ? qq{$1 $2} : $2;
}
'
! FLOAT_CODE
FIXED_CODE