Re: What's your favourite *under_publicized* editing feature of Emacs?

[Perry Smith]

On Feb 17, 2011, at 4:53 AM, Giorgos Keramidas wrote:

On Sat, 29 Jan 2011 09:02:14 -0600, Perry Smith <pedzsan@gmail.com> wrote:

This thread is beginning to drift a bit... but something I wish I had

was a way to view a file without loading all of it.  I look at hugh

trace files and I have to get out of emacs and start a shell so I can

use more / less.

The shame of it all! ;-)

I don't know of such a critter.  If there is one, that would be super

cool.

If there was some way to lazy-load files, I'd be happy too.

I looked at this.  The approach I was going to take was to put into the C code

an "open", "close", "read", and "lseek" concept and that would need a new

"type" for a file descriptor.  You might as well add "write" to complete the set.

There is nothing currently like that in the C code.  I'm not sure if you want

to put this on top of open and its siblings or on top of fopen and let the C

I/O help some with the buffering.

From there, it becomes a matter of writing lisp to load in a "page" into a

buffer so it can be displayed and then a key map so the user can page

forward and backward.  For searches I couldn't come up with a nice

solution so I was just going to loop loading a page and searching the page

until the match was found.

The second generation of this could have a fixed sized cache of pages so that

small movements (like back a page) would be instant and you could even

get fancier and pre-fetch the next page.

This could grow into a hugh beast.  You would want to hook up to the

character set things so that it would detect and process all the different

characters sets (like UTF-8, etc) properly.  And then, what the hell, you

might as well plop the nifty coloring modes on top as well so that

as you page through C text, it would be colored.  In my case, I want to

plop a wireshark mode on top so that I can view network packets.

But, for my own personal case, I have way too many projects going already

so I didn't even post this to the list until just now.  I think its a concept

whose time has come but I don't have the time right now.  I'd love to

contribute to it if anyone wants to start.

Perry