> The problem with application-specific extension languages is that they may start underpowered and ad-hoc, whilst general purpose languages have already proved their worth and done so in several domains.

The embedded language has to be small, easy to learn, and most importantly, it should serve the purpose of extension. If it can serve other domains as well, that isn't really relevant as far as the editor is the concerned. Now vimscript doesn't do threading or evented io or thousands of other things - it isn't meant to do any of those.

> whilst GNU Emacs designers didn't reinvent the wheel and adapted a mainstream general purpose language to their needs.

Lisp can hardly be considered a mainstream, general purpose language(may be it was at the time they were adding it to emacs).

The point of vimscript wasn't to win any language design awards, but to have a langauge with a very small core which can be used for configuration and extension. As far as quirks go, all languages have quirks. PHP and JS probably have more quirks than Vimscript. Since you are so critical of Vimscript, care to cite me the pain-points which stop you from writing decent extensions in vimscript? There are a variety of scenarios in which vimscript implementation is much more simpler to an elisp implementation.

Consider this sample grap extension take from Steve Losh's http://learnvimscriptthehardway.stevelosh.com/chapters/34.ht...

nnoremap <leader>g :set operatorfunc=<SID>GrepOperator<cr>g@
vnoremap <leader>g :<C-U>call <SID>GrepOperator(visualmode())<cr>

function! s:GrepOperator(type)
let saved_unnamed_register = @@

if a:type ==# 'v'
normal! `<v`>y
elseif a:type ==# 'char'
normal! `[v`]y
else
return
endif

silent execute "grep! -R " . shellescape(@@) . " ."
copen

let @@ = saved_unnamed_register
endfunction

And usage:

viw<leader>g: Visually select a word, then grep for it.
<leader>g4w: Grep for the next four words.
<leader>gt;: Grep until semicolon.
<leader>gi[: Grep inside square brackets.

Are you saying elisp implementation of the same concept(provide me a way to grep for arbitrary grep for words, and no, spawning a shell isn't the same thing) is going to be shorter or simpler?

> While Vim users were busy wrestling with the limitations of their extension language

I would really like examples where the limitation of vimscript is outshined by elsip. Check my snippet above - vimscript is written specifically for extending vim, and it does a good job.

> Emacs users were busy churning out macros and packages for their editor.

I find recording macros in vim simpler than emacs. By default. Vim doesn't have a save macro functionality, but either you use an extension to do that, or manually save the macro.

> The main reason I have chosen Emacs as my editor is that I get more bang for the buck.

It mostly boils down to this "I get more bang for the buck". There is not much objectiveness when it comes to vim and emacs. You enjoy emacs, I enjoy vim.

> Emacs can emulate Vim,

A very limited form of vim navigation.

> whilst the opposite is not true, as the folks who tried to port SLIME (a powerful package to code in Common Lisp) realized.

I didn't know about an attempt to port slime to vim, because you will have to fight vim for it, and vim won't yield. Vim doesn't do async processes and per the developers, it's not going to, period. So, no shells in the vim(you can folk a shell but then the editor goes away and when you exit the shell, you are back in the editor), no debugger, no slime...It's a conscious design decision. If you don't like it, use something else.