(defun next-minipage () (interactive)
  (goto-char (search-forward "\f\n"))
  (recenter 0))

(defun previous-minipage () (interactive)
  (backward-char)
  (goto-char (+ 2 (search-backward "\f\n")))
  (recenter 0))

(define-key my-mode-map (kbd "S-<up>")   'previous-minipage)
(define-key my-mode-map (kbd "S-<down>") 'next-minipage)

;; (find-estring "\f\nFirst minipage\n\n\f\nSecond\n\n\f\nThird\n")

;; http://angg.twu.net/eev-current/slides/
;; http://angg.twu.net/eev-current/slides/slides-pt.tex
;; http://angg.twu.net/eev-current/slides/dec2006-pt.txt
;; (find-pspage "~/eev-current/slides/slides-pt.ps")
;; (find-pspage "~/eev-current/slides/slides.ps")
;; (find-sh "gsub.lua '\f' '^L' < ~/eev-current/slides/dec2006-pt.txt")
;; (find-sh "tr '\f' '_' < ~/eev-current/slides/dec2006-pt.txt")
;; (find-anggfile "bin/gsub.lua")
;; (eea2ps (point-min) (point-max))
* (eepitch-shell)
gsdj-tmp ~/o.ps
cd /tmp/
laf
cat o.p001 > /dev/lp0
cat o.p002 > /dev/lp0




Emacs: história
===============

1958: Lisp       <- linguagem
1963: TECO       <- editor programável
1970: Unix       <- sistema operacional

1975: Emacs (versão em TECO)
1976: Emacs (primeiras versões em Lisp)

1979: artigo (Richard Stallman):
      "EMACS: The Extensible, Customizable Display Editor"
1983: GPL
1983: Projeto GNU

Refs: http://www.jwz.org/doc/emacs-timeline.html
      http://www.gnu.org/software/emacs/emacs-paper.html


TECO: exemplo de programa
=========================
(http://en.wikipedia.org/wiki/Text_Editor_and_Corrector#Example_2)

0uz                        ! clear repeat flag !
<j 0aua l                  ! load 1st char into register A !
<0aub                      ! load 1st char of next line into B !
qa-qb"g xa k -l ga -1uz '  ! if A>B, switch lines and set flag !
qbua                       ! load B into A !
l .-z;>                    ! loop back if another line in buffer !
qz;>                       ! repeat if a switch was made last pass !

"


Lisp: primeiros exemplos
========================

(+ 1 2)
  -> 3
(* (+ 1 2) (+ 3 4))
  -> 21
(list (+ 2 3) (* 4 5))
  -> (5 20)
(car (list (+ 2 3) (* 4 5)))
  -> 5
(cdr (list (+ 2 3) (* 4 5)))
  -> (20)



Lisp: mais exemplos
===================

;; Calcula 20+21+22+...+50:
(let ((total 0)
      (i 20))
  (while (<= i 50)
    (setq total (+ total i))
    (setq i (+ i 1)))
  total)
    -> 1085

;; Calcula 5^2:
(defun square (n) (* n n))
  -> square
(square 5)
  -> 25
(defun cube (n) (* n (square n)))
  -> cube
(cube 5)
  -> 125


Lisp "matemático" versus Lisp "computacional"
=============================================

Lisp "computacional":
* strings e conses são representados por endereços
  de memória
* duas funções de comparação:
  * eq: rápido, compara endereços
  * equal: lento, compara estruturas

    (eq    (list 1 2) (list 1 2))
      -> nil
    (equal (list 1 2) (list 1 2))
      -> t

* garbage collection


Como assim, "Lisp é poderoso"?
==============================

A definição de "Universal Turing Machine" (1936) é bem
complicada...

Uma versão do "eval" original (1958), em Lisp moderno:
  http://www.paulgraham.com/rootsoflisp.html
  http://lib.store.yahoo.net/lib/paulgraham/jmc.lisp

Pergunta: Pra que queremos isso?
Resposta: Modificando o "eval" nós modificamos a linguagem...
  O Lisp original não tem nem "let", nem "while", por exemplo.

Qualquer Lisp lisp 

Idéia original (Turing, 1936):


"...the primary representation of program code is the same type of
list structure that is also used for the main data structures. As a
result, Lisp functions can be manipulated, altered or even created
within a Lisp program without extensive parsing or manipulation of
binary machine code." (wikipedia: Lisp)
-- 



(find-



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