Literals

The only literals accepted as tokens are integer and float numbers.

Literal	Size / precision
Integer	64-bit signed
Float	IEEE 754 double precision

Grammar of number literals

integer-literal:
  digit-sequence

floating-literal:
  digit-sequence . digit-sequence exponent_opt
  digit-sequence . exponent_opt
  . digit-sequence exponent_opt

exponent:
  e sign_opt digit-sequence
  E sign_opt digit-sequence

sign: one of
  + -

digit-sequence:
  digit
  digit-sequence digit

digit: one of
  0 through 9