Allow expressions in the REPL

[ldilley]

Feature Description

• Allow expressions such as 1 + 2 or 1 > 0 in the REPL without an identifier and assignment operator. Currently, in interactive mode, the parser spits the following error rather than evaluate each expression (expected output below should be 3 and true):

> 1 + 2
Parsing error: [1] Expected a statement, got Int
> 1 > 0
Parsing error: [1] Expected a statement, got Int

Perhaps a relaxed mode could be added to cct_new_parser() when using a string lexer (and not file based).