Ok. Still working on this...
Looking in the source of src/print.c I found the definition of "#^^[" it signifies a sub char-table, as I sort of suspected by the pp command's indentation..

Here's print.c

    if (CHAR_TABLE_P (obj) || SUB_CHAR_TABLE_P (obj))
        {
          /* We print a char-table as if it were a vector,
        lumping the parent and default slots in with the
        character slots. But we add #^ as a prefix. */

          /* Make each lowest sub_char_table start a new line.
        Otherwise we'll make a line extremely long, which
        results in slow redisplay. */
          if (SUB_CHAR_TABLE_P (obj)
        && XINT (XSUB_CHAR_TABLE (obj)->depth) == 3)
        PRINTCHAR ('\n');
          PRINTCHAR ('#');
          PRINTCHAR ('^');
          if (SUB_CHAR_TABLE_P (obj))
        PRINTCHAR ('^');      <---- The second caret! aha
....

Then from lisp.h...
    /* Depth of this sub char-table. It should be 1, 2, or 3. A sub
       char-table of depth 1 contains 16 elments, and each element
       covers 4096 (128*32) characters. A sub char-table of depth 2
       contains 32 elements, and each element covers 128 characters. A
       sub char-table of depth 3 contains 128 elements, and each element
       is for one character. */
    Lisp_Object depth;

OK, so the contents of the esc-map, a standard keymap, use this as mentioned in my first post.
eg
(pp esc-map)
=> "(keymap #^[ nil nil keymap #^^[3 0 mark-sexp beginning-of-defun ....)"

and then
(aref (nth 1 esc-map) 0)
=> mark-sexp

What i don't understand is why when i use aref to fetch the 0th element of the char-table as above, why it returns the 0th element of the sub-char table.

This does not seem to be in either the elisp or emacs manual as Pascal B was quick to assume.

I feel like it's a long shot- but does anyone have any answers?

On Sat, Mar 31, 2012 at 10:10 PM, HD <heavydeuterium@gmail.com> wrote:

Hello.
When I evaluate "(pp esc-map)" it pretty-prints a keymap that starts with the lines

(keymap
#^[nil nil keymap
#^^[3 0 mark-sexp beginning-of-defun backward-sexp ...

...and so on

Can someone explain this syntax?
eg Why is keymap the 3rd element in the char-table, and what does the "nil nil" before it signify?
What is "#^^[3 0" ? What do the 3 and 0 mean here?

why does "(aref (nth 1 esc-map) 0)" return "mark-sexp"?

I couldn't find answers in the manuals for emacs or elisp, except maybe that "#^[ nil nil keymap" means character code 3 corresponds to a keymap in this char-table

-HD