find regex for Unmarked Reals $($RCONST$)$:

Zero or more numeric characters followed by the $\text{'}.\text{'}$ character and

at least one numeric character, or at least one numeric character that

optionally followed by the $\text{'}.\text{'}$ character and zero or more numeric characters

characters. Optionally follows an exponent field, starting with the character $\text{'}$E$\text{'},$ followed by

followed by an optional sign and at least one numeric character. If not

there is an exponent field, the number can be in hexadecimal, octal or binary

base, with corresponding prefix $0$X$,0$O$$ or $0$B$.$ The integral part of the constant, as well as

the numerical part of the exponent cannot start with $\text{'}0\text{'}$ if it is not $\text{'}0\text{'}.$ In any case

if there is a fractional part, this must include at least one character

carrier other than $\text{'}0\text{'},$ unless it is $\text{'}0\text{'}.$ Finally, constants that have are excluded

already defined as integers