CoCoA » CoCoA-5

I think it should not be too hard to add an "exit" command, but this means introducing a new keyword which could, in principle, break existing code (if someone has used "exit" as a variable/fn name).

What I did to add command "exit".

cd src/CoCoA-5
fgrep Ciao Lexer.C
--> Keyword("Ciao", TT_CIAO)

In Lexer.H add TT_EXIT to enum TokenType
In Lexer.C add Keyword("Exit", TT_EXIT) to keywordTable

In Parser.C 3 changes:
(1) add case TT_EXIT to UnexpectedTokenException::humanReadable(...)
(2) add case TT_EXIT to mayStartOrFollowAStatement(...)
(3) add case TT_EXIT to Parser::parseFunBodyStatement()

In AST.C 2 changes:
(1) add appropriate dumpAsString(...) mem fn
[in this case just modify an existing one]
(2) add appropriate DumpAsTreeVisitor::visit(...) fn
[in this case just modify an existing one]

In C5.C add "Exit" to keywordRE (in CocoaHighlighter ctor around line 460)

Running "make" produced a CoCoAInterpreter but "exit" did not work properly.
After doing "make clean; make" it worked fine.

PS I also added "exit" to the CoCoAManual!

I have also change the "goodbye pop-up window" in the GUI so that it says "Ciao" instead of "Bye".