trajber: vou pedir ajuda ao meu querido PC
trajber: mauro@trajber:~$ python
Python 2.5.2 (r252:60911, Oct 5 2008, 19:24:49)
[GCC 4.3.2] on linux2
Type “help”, “copyright”, “credits” or “license” for more information.
>>> import random
>>> print random.randint(0,1)
trajber: 0 = ignorar
trajber: 1 = comer
trajber: ok ?
trajber: 0
>>>
trajber: foi justo…

Outro também fez algo parecido: http://twitter.com/igorrs/status/896944758

Time is always critical because somebody might beat you to the punch

Founders at Work, Jessica Livingston

• Grab the nearest book.
• Open it to page 56.
• Find the fifth sentence.
• Post the text of the sentence in your journal along with these # instructions.
• Don’t dig for your favorite book, the cool book, or the intellectual one: pick the CLOSEST.

(eval-when (:compile-toplevel :load-toplevel :execute)
  (defparameter *dependencies*
    ‘(:asdf :hunchentoot :ht-ajax :cl-who :parenscript))
  (map nil ‘require *dependencies*))

(defpackage :ajax-test
  (:use :common-lisp :hunchentoot :ht-ajax :cl-who :parenscript))

(in-package :ajax-test)

(defparameter *local-dir* “/Users/lucindo/Documents/Lisp/web/3rdparty/”)
(defparameter *ajax-handler-url* “/ajax”)
(defparameter *ajax-processor*
  (make-ajax-processor :type :jquery
                       :server-uri *ajax-handler-url*
                       :js-file-uris “/static/jquery.js”))

(defun testfunc (command)
  (prin1-to-string (handler-case (eval (read-from-string command nil))
                                 (error (c) (format nil “~a” c)))))

(defun js ()
  (ps
   (defun command_clicked ()
     (let ((command (document.get-element-by-id “command”)))
       (with-slots (value) command
                   (ajax_testfunc_set_element “result” value))))))

(defun main-page ()
  (with-html-output-to-string
   (*standard-output* nil :prologue t)
   (:html
    (:head
     (:script :type “text/javascript” :src “/js”)
     (:title “AJAX test”)
     (fmt “~a” (generate-prologue *ajax-processor*)))
    (:body
     (:h1 “ajax test”)
     (:table :width “50%”
             (:tr
              (:td :colspan “2″
                   (:span :id “result”
                          (:i “no results yet”))))
             (:tr
              (:td :width “70%”
                   (:input :type “text”
                           :size “70″
                           :name “command”
                           :id “command”))
              (:td (:input :type “button”
                           :value “eval”
                           :onclick (ps-inline (command_clicked))))))))))

(eval-when (:load-toplevel :execute)
  (export-func *ajax-processor* ‘testfunc :method :post)
  (setf *dispatch-table*
        (list ‘dispatch-easy-handlers
              (create-folder-dispatcher-and-handler “/static/”
                                                    *local-dir* “text/plain”)
              (create-prefix-dispatcher *ajax-handler-url*
                                        (get-handler *ajax-processor*))
              (create-prefix-dispatcher “/js” ‘js)
              (create-prefix-dispatcher “/” ‘main-page))))

(defparameter *webserver* nil)

(defun start-web (&optional (port 4242))
  (setf *webserver* (start-server :port port)))

(defun stop-web ()
  (stop-server *webserver*))

Download: ajax2.lisp

Veja se o defined? não funciona de maneira não intuitiva:

lucindo@marvin:~$ irb
irb(main):001:0> defined?(cu)
=> nil
irb(main):002:0> if false
irb(main):003:1>    cu = "ruby"
irb(main):004:1> end
=> nil
irb(main):005:0> defined?(cu)
=> "local-variable"
irb(main):006:0> if defined?(cu)
irb(main):007:1>    puts "ruby cu"
irb(main):008:1> end
ruby cu
=> nil
irb(main):009:0>

Imagina se você usa isso em algo como configuração…

Estou tentando mudar para Python como a minha principal linguagem de script, mas ainda preciso aprender a programar direito nessa linguagem. Enquanto isso não acontece, eu fico replicando código de outros lugares, como a cópia de pobre da ACE_Task abaixo:

import threading, Queue, signal

class Task(object):
    def __init__(self):
        self.queue = Queue.Queue(0)

    def __worker(self):
        while True:
            item = self.queue.get()
            self.process(item)
            self.queue.task_done()

    def __start(self):
        thread = threading.Thread(target=self.__worker)
        thread.setDaemon(True)
        thread.start()

    def activate(self, threads):
        for thread in xrange(threads):
            self.__start()
        signal.signal(signal.SIGINT, signal.SIG_DFL)

    def put(self, item):
        self.queue.put(item)

    def wait(self):
        self.queue.join()

    def process(self, item):
        pass

class task(Task):
    def __init__(self, func):
        Task.__init__(self)
        self.process = func

A única coisa pytônica do código é o decorator do final.

Bom, um exemplo de uso: digamos que você é um spammer e quer mandar vários emails. Você tem um arquivo em que cada linha tem as seguintes informações: servidor; email; subject; mensagem. Tudo separado por ponto e vírgula.

Usando o decorator acima o código ficaria mais ou menos assim (usando 100 threads):

from __future__ import with_statement
from task import task
import smtplib, sys

@task
def send_spam(item):
    server, toaddr, subject, msg = item.strip().split(‘;’)
    fromaddr = ’spammer@evil.org’
    message = (“From: %s\r\nTo: %s\r\nSubject: %s\r\n\r\n%s”
               % (fromaddr, toaddr, subject, msg))
    try:
        smtp = smtplib.SMTP(server)
        smtp.sendmail(fromaddr, toaddr, message)
    except Exception:
        pass

def process_file(filename):
    send_spam.activate(100)
    with open(filename) as file:
        map(lambda line: send_spam.put(line), file.readlines())
    send_spam.wait()

if __name__ == ‘__main__’:
    process_file(sys.argv[1])

Coloquei esse exemplo porque não tinha um melhor… é apenas um exemplo, não um programa de verdade, ok?

Download: task.py

To do: reescrever em Python 2.6 usando Multiprocessos

Eight years to do TeX? How smart can he be? He should have used Lisp.

Kenny Tilton, sobre Donald Knuth

HT-AJAX suporta vários AJAX processors, como Prototype e Dojo, mas não jQuery. Então fiz um pequeno patch adicionando suporte a jQuery.

Download: ht-ajax_0.0.7-jquery.patch

Aplicando o patch (SBCL):

$ cd ~/.sbcl/site/ht-ajax_0.0.7
$ wget http://lucindo.com.br/lisp/ht-ajax_0.0.7-jquery.patch
$ cat ht-ajax_0.0.7-jquery.patch | patch -p0
$ sbcl
* (require :asdf)
* (asdf:oos 'asdf:compile-op :ht-ajax)

Two options for lispers:

• Purely functional Lisps (subset of CL or something like Clojure, LFE, etc)
• Cells!!!

I’m completely convinced that mutable objects and the whole approach that is sort of implied by the design of Java, C#, Python, all the languages that followed along this path, is very much the wrong way to do most things… it is ok to do somethings, but it’s the wrong way to do most things.
Mutable objects are the new spaghetti code, and by that I mean that you eventually, with mutable objects, create an intractable mess, and encapsulation does not get rid off that, encapsulation just means: well, I’m in charge of this mess. But the real mess comes from this network you create of objects that can change, and your inability to look at the state of a system and understand how you got there, how to get there to test it next time… so it’s hard to understand the program… it’s very hard to test it. I think that’s interesting in telling all the emphasis on test driven design. I think people are driven to this because they know their systems are completely intractable…

Rich Hickey - Screencast: Clojure Concurrency (”transcrição” do minuto 21 ao 23)