`NumTok`

Numbers in different forms: signed or unsigned, possibly with fractional part and exponent.

Numbers are represented using raw strings of (hexa)decimal literals and a separate sign flag.

Note that this representation is not unique, due to possible multiple leading or trailing zeros, and -0 = +0, for instances. The reason to keep the number exactly as it was parsed is that specific notations can be declared for specific numbers (e.g. `Notation "0" := False`

, or `Notation "00" := (nil,nil)`

, or `Notation "2e1" := ...`

). Those notations override the generic interpretation as number. So, one has to record the form of the number which exactly matches the notation.

`module UnsignedNat : sig ... end`

`module SignedNat : sig ... end`

`module Unsigned : sig ... end`

`module Signed : sig ... end`