Re: Reading huge files

[Mathias Dahl]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> You'll indeed need something like that.  I'd recommend to use `dd'
> rather than `split' or `head&tail'.

Thanks for the hint, I will take a look at that.

> But note that the problem is bigger than you think: the above will
> need to work with floating-point arguments (since fixnums suffer
> from the 2^28 limit) and the %d format also suffers from the 2^28
> limit (or 2^31 in Emacs-CVS).

After I read Eli's comment about the integer problem I added back the
head-tail version into the code (configurable) and then I started to
notice problemd with integers in various places, so I started to look
into using float, which solved some problems (I am using %.0f instead
of %d now in the call to `format', for example). There still seems to
be some problems though.

>  That's another good reason to use
> `dd' since you can use a 1048576 block size and thus divide your
> large floats by 1048576 before turning them into fixnums.

Umm, okay... (I did not understand half of that, but I probably will
after looking into it.. :)

> Please just use
>
>   (defvar vlf-mode-map
>     (let ((map (make-sparse-keymap)))
>       (define-key map [next] 'vlf-next)
>       (define-key map [prior] 'vlf-prev)
>       (define-key map "q" 'vlf-quit)
>       map)
>     "Keymap for `vlf-mode'.")

Ah, of course! :) The reason I do that is that when testing and adding
key bindings, I cannot simply reevaluate that defvar (because it won't
"bite"), so I use a function to set the map instead and then I can
reevaluate a call to this function.
  
> Also, wrt features, it'd probably be good to "slide more smoothly":
> e.g. always keep 2 or 3 blocks in the buffer at the same time so you
> can comfortably look at the text at the boundaries between blocks.

> Next step: use window-scroll-functions or jit-lock to detect when
> reaching one of the ends so that we can automatically load in the
> next consecutive block.

Aaargh, all these feature-requests make me crazy! :)