The future of Emacs, Guile, and Emacs Lisp

Posted Oct 21, 2014 16:30 UTC (Tue) by nix (subscriber, #2304)
In reply to: The future of Emacs, Guile, and Emacs Lisp by Cyberax
Parent article: The future of Emacs, Guile, and Emacs Lisp

It's sufficient for what I want to do with it for C.

Obviously getting it right for C++ is impossible -- but you need a C++ compiler to understand C++ properly. Actually you need something *better*, because you want to be able to parse incomplete, partially written, and syntactically invalid code as much as possible. That sort of error recovery is *hard*.

The future of Emacs, Guile, and Emacs Lisp

Posted Oct 21, 2014 16:36 UTC (Tue) by Cyberax (✭ supporter ✭, #52523) [Link] (2 responses)

Clang mostly gets error recovery right. Aside from them, people at IntelliJ are working on Nitra ( https://github.com/JetBrains/Nitra ) are trying to make it easier for complicated languages and they are tackling C++ now.

Pure C is also not that easy, because lots of C++'s syntactic ambiguity actually comes from C.

The future of Emacs, Guile, and Emacs Lisp

Posted Oct 23, 2014 1:34 UTC (Thu) by cmccabe (guest, #60281) [Link] (1 responses)

C is "very close to having a context-free grammar."
Details here: http://eli.thegreenplace.net/2007/11/24/the-context-sensi...

C++ has an undecidable grammar.

I can parse C with yacc. I could never hope to parse C++ with anything but a hand-written parser.

The future of Emacs, Guile, and Emacs Lisp

Posted Oct 23, 2014 11:41 UTC (Thu) by jwakely (subscriber, #60262) [Link]

Yeah, C doesn't have to parse anything remotely like:

int Foo (int i = T<1, int>::i);

(See http://open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#325 for other examples like that)