5 ms·

Woah, emacs lisp now has lexical scoping

intranation 14y ago
It's opt-in, otherwise most packages would break. To enable it per-file use a file-local variable: ;;; -*- lexical-binding: t -*-
- perlgeek 14y ago
  How ironic. Wouldn't it make much sense to enable it per lexical scope? Or as Perl did it (18 years ago) with a new keyword, so that you can use both dynamic and lexical variables in the same file? Best of both worlds.
  - m00natic 14y ago
    Well, there has been lexical-let in the cl package for quite a while.
  - onedognight 14y ago
    You can use both in the same file; you just need to declare the dynamic ones using defvar, etc. If you turn lexical-binding on blindly, the compiler will usually tell you which variables you need to mark as dynamic.
  - unhammer 14y ago
    (eval form t) enables lexical scoping for form. http://yoo2080.wordpress.com/2011/12/31/lexical-scoping-and-dynamic-scoping-in-emacs-lisp/ http://yoo2080.wordpress.com/2011/12/31/lexical-scoping-and-... is highly recommended reading btw.
  - rcthompson 14y ago
    It has to be this way to remain backward-compatible. Similar to the issues Perl is going through with things like enabling strict by default (you have to request at least a certain version, I think 5.12), and distinguishing a Perl 6 file from Perl 5 one.
conanite 14y ago
Yes, this is pretty radical. More info from the manual: http://www.gnu.org/software/emacs/manual/html_node/elisp/Using-Lexical-Binding.html http://www.gnu.org/software/emacs/manual/html_node/elisp/Usi... from http://www.gnu.org/software/emacs/manual/html_node/elisp/Lexical-Binding.html http://www.gnu.org/software/emacs/manual/html_node/elisp/Lex... - Such code is also much more friendly to concurrency, which we want to add to Emacs in the near future. Exciting times ahead ...
- ams6110 14y ago
  Indeed, will be nice when something blocking in one window doesn't lock up the whole emacs process.
  - Derbasti 14y ago
    Yes, ohhh, yes, I want that!
  - unhammer 14y ago
    YES! E.g. try running emacs on $host and run bbdb; go to some other machine and ssh ~/.bbdb $host:~/.bbdb; then ssh $host emacsclient. Now it's unresponsive until you walk over on your feet to $host and answer the revert-or-not question :(

It's opt-in, otherwise most packages would break. To enable it per-file use a file-local variable: ;;; -*- lexical-binding: t -*-

perlgeek 14y ago
How ironic. Wouldn't it make much sense to enable it per lexical scope? Or as Perl did it (18 years ago) with a new keyword, so that you can use both dynamic and lexical variables in the same file? Best of both worlds.
- m00natic 14y ago
  Well, there has been lexical-let in the cl package for quite a while.
- onedognight 14y ago
  You can use both in the same file; you just need to declare the dynamic ones using defvar, etc. If you turn lexical-binding on blindly, the compiler will usually tell you which variables you need to mark as dynamic.
- unhammer 14y ago
  (eval form t) enables lexical scoping for form. http://yoo2080.wordpress.com/2011/12/31/lexical-scoping-and-dynamic-scoping-in-emacs-lisp/ http://yoo2080.wordpress.com/2011/12/31/lexical-scoping-and-... is highly recommended reading btw.
- rcthompson 14y ago
  It has to be this way to remain backward-compatible. Similar to the issues Perl is going through with things like enabling strict by default (you have to request at least a certain version, I think 5.12), and distinguishing a Perl 6 file from Perl 5 one.

conanite 14y ago

Yes, this is pretty radical. More info from the manual: http://www.gnu.org/software/emacs/manual/html_node/elisp/Using-Lexical-Binding.html http://www.gnu.org/software/emacs/manual/html_node/elisp/Usi... from http://www.gnu.org/software/emacs/manual/html_node/elisp/Lexical-Binding.html http://www.gnu.org/software/emacs/manual/html_node/elisp/Lex... - Such code is also much more friendly to concurrency, which we want to add to Emacs in the near future. Exciting times ahead ...

ams6110 14y ago
Indeed, will be nice when something blocking in one window doesn't lock up the whole emacs process.
- Derbasti 14y ago
  Yes, ohhh, yes, I want that!
- unhammer 14y ago
  YES! E.g. try running emacs on $host and run bbdb; go to some other machine and ssh ~/.bbdb $host:~/.bbdb; then ssh $host emacsclient. Now it's unresponsive until you walk over on your feet to $host and answer the revert-or-not question :(