Re: Byte-compiling the line specs

[raeburn@cygnus.com (Ken Raeburn)]

   From: Per Abrahamsen <abraham@dina.kvl.dk>
   Date: Tue, 31 Oct 1995 15:13:59 +0100

   I get a bit more encouraging results with Emacs 19.29 and the
   following code:

   (let ((i 100000)
   ...


   Here is the timings:

			   Min     Max
   -----------------------------------------
   Empty Loop               5       6
   "99999"                  7       8
   princ                   13      14
   format                  19      20
   number-to-string        16      17

   The three first didn't generate any garbage, while the two last
   triggered a lot of garbage collections.

Did you byte-compile the loop?  If you're interested in comparing just the
formatting and insertion mechanisms, I think it's a good idea.

I tried it.  (Byte-compiled the file, read it into a buffer, moved to the
end, ran eval-current-buffer and then eval-last-sexp a couple of times, to
get three values.)  The princ test was faster than both number-to-string
and format by about a factor of 3 (though the numerous gc passes may have
been another factor contributing to getting different results from yours).
The number-to-string and format timings were closer than in your tests.

I also experimented with some elisp code for computing the character
values to insert, using % and / and adding to ?0, and using the "insert"
byte-code opcode.  That eliminated the garbage collection, but only saved
about 20% over number-to-string and format.

I think princ is probably the way to go, at least for numbers.  Numeric
fields padded to a specified width might be another matter, though....