overload::constant
It is meant to work a bit like P5's overload::constant[1], though it is kind of pre-alpha here.
USAGE
sub integer { "i$^a" }
sub decimal { "d$^a" }
sub radix { "r$^a" }
sub numish { "n$^a" }
use overload::constant &integer, &decimal, &radix, &numish;
ok 42 ~~ Str && 42 eq 'i42', 'can overload integer';
ok 0.12 ~~ Str && 0.12 eq 'd0.12', 'can overload decimal';
ok .1e-003 ~~ Str && .1e-003 eq 'd.1e-003', 'can overload decimal in scientific notation';
ok :16<FF> ~~ Str && :16<FF> eq 'r:16<FF>', 'can overload radix';
ok NaN ~~ Str && NaN eq 'nNaN', 'can overload other numish things';
[1] http://perldoc.perl.org/overload.html#Overloading-Constants