Aidan Kehoe writes: > changeset: 4677:8f1ee2d15784 > user: Aidan Kehoe <kehoea(a)parhasard.net&gt; > date: Sun Aug 16 20:55:49 2009 +0100 > files: lisp/ChangeLog lisp/byte-optimize.el lisp/bytecomp.el lisp/cl-compat.el lisp/cl-macs.el lisp/cl.el lisp/lisp-mode.el lisp/mouse.el lisp/obsolete.el man/ChangeLog man/cl.texi src/ChangeLog src/bytecode.c src/callint.c src/device-x.c src/eval.c src/event-msw.c src/event-stream.c src/glade.c src/glyphs-widget.c src/glyphs.c src/gui-x.c src/gui.c src/inline.c src/lisp.h src/lread.c src/lrecord.h src/macros.c src/menubar-gtk.c src/menubar-msw.c src/print.c src/symbols.c src/symeval.h > description: > Support full Common Lisp multiple values in C. Would somebody please remind me why we need to support this feature, given that it requires strewing unlovely stuff (some of which even the author needs to tag with "Ugh") throughout not only the core code but the packages too expose very tricky static functions to the global scope, changes the semantics of the trickiest function in the whole Lisp engine (throw was a function, now it's a special form), adds instructions to the inner loop of the bytecode interpreter, and complexifies the implementation of the byte code interpreter?

This seems to be a very large cost for something that is pretty much a YAGNI in Emacs. Existing uses are served quite well by the cl.el implementation (especially since a large number of them are just plain broken but apparently work anyway).

On 2009-08-17, Aidan Kehoe <kehoea(a)parhasard.net&gt; wrote: > The thing that prompted my interest in multiple values was providing a > decent API for #'query-coding-region. That was my need, I wanted it to > return t if the region was encodable and return nil plus further information > (acquired in the course of executing the function) if it was not. And no, And it was worth all that work to avoid defining an API where the old "return value" is the car of a returned list, or the extra information is stashed into a variable? That's some devotion to theoretical elegance!

> Every other dynamic language out there of note has this feature, by the way. I think TeX is of note;-)