Lexer scans through a line of code int A1=5 and try to match a regular expression to cut out the token start from the beginning of the line. The first one to cut out would be , then the lexer tries to match the second token starting from A in int A1=5 and should find out , and so on. Find the regular expression for the tokens.

Please use python

Operator is defined as:

Its regular expression should be:

Keywords:

Its regular expression should be:

Separators:

Its regular expression should be:

Identifiers:

Its regular expression should be:

Literals:

Its regular expression should be: