Re: mode line eol char indication

[Jason Rumney]

Drew Adams wrote:
> * The non-"nontrivial" eol convention, represented by `:', is
>   presumably what is meant by "usually", that is, a newline char.
>   But a newline eol is also sometimes represented by `(Unix)'.
>   Why?  And why is this called "nontrivial" - why is it more
>   nontrivial and more usual than the other possibilities?
>   

In Emacs 20, only the single character indications were used, but people 
found them confusing. But the full word indications are too long for 
many people, so now we use the single character when the newline format 
is native for the platform Emacs is running on, and the full word when 
it is non-native - this change occurred in 21.1 IIRC. Unix line ends are 
non-trivial because they are what Emacs uses internally - no conversion 
is required. They are more usual for users of GNU based platforms 
because GNU is based on unix conventions.

> Why `:'?  Why `\' (is there some relation to the DOS directory
> separator?)?  Why `/'?
>   
.
Originally : was was based on the unix PATH separator, and \ on the DOS 
directory separator. / was made the Mac indicator because like the DOS 
separator, it is not straight up and down, but it leans a different 
direction than DOS. I think at some point during 20.1 pretest, we had / 
for Unix and : for Mac, until someone pointed out that : was less 
noticeable, so that should indicate the trivial Unix line-end.