[MLton] Tabs in source files

[Matthew Fluet]

> I don't want to start a holy war, but I would like to suggest not using
> tabs in source files.
> The main
> problems with tabs are broken indentation (with different tab widths)
> and unnecessary (pure indentation) diffs. The savings in source code
> size offered by tabs is unlikely to be important and should not have a
> significant effect on the speed of something like CVS operations when
> using compression. When indentation uses only spaces, the code just
> always looks like it was intended.

It is a fair rationale, but is there a reasonable implementation?

> MLton is, of course, a different project and I'm biased as I personally
> don't use tabs and have set
> 
>   '(indent-tabs-mode nil)
> 
> in my XEmacs custom.el (Makefile editing still works fine). 

indent-tabs-mode is unknown by my emacs (21.2.1).

How do you keep tabs from appearing in MLton source code, but allow a
developer to use tabs freely in other projects/documents?  How do you do
this without requiring a developer to use Emacs?  Will my Emacs
auto-indentation for formatting still work?