Error in lexing negative number

[daeisbae]

Problem

• Negative number is not lexed as integer instead is lexed as negative operator and integer.

Demo

/AParser                                                                                                                                                                                ─╯
>>> -1
libc++abi: terminating due to uncaught exception of type UnexpectedTokenParsedException: Unexpected Operator: 'Operator( Value: '-' )' is not allowed
[1]    17509 abort      ./AParser

and

./AParser                                                                                                                                                                                ─╯
>>> set a = -1
libc++abi: terminating due to uncaught exception of type UnexpectedTokenParsedException: Unexpected Operator: 'Operator( Value: '-' )' is not allowed
[1]    17512 abort      ./AParser

[daeisbae]

Fixed in #61