没有人是一座孤岛

可以自全。

每个人都是大陆的一片，

整体的一部分。

如果海水冲掉一片，

欧洲就减少，

如同一个海岬失掉一角，

如果你的朋友或者你自己的领地失掉一块：

任何人的死亡都是我的损失，

因为我是人类的一员，

因此

不要问丧钟为谁而鸣，

它就为你而鸣。

Crawling comics

Recently, I was reading bleach comics from the internet.

But when I read those comics, I realise the image loading is relatively slow due to the internet connectivity. So I was considering if I can write any scripts to save images locally for quick reading.

For this task, I applied scrapy python spider framework for crawling automation. However, most of comics are using lazy loading technology, which utilizes JavaScript code to load images. For lazy loading, the images can not be loaded only from html static context. There are two potential solutions to handle this trouble:

1. Call python library to run browser to activate javascript code functionality.
2. Use some javascript libraries to load page and then run crawling.

In this post, we start to explore the magic of emacs: customized configuration files for emacs. The magic feature of emacs is the extensibility. Comparing to Vim, which is the specialist as a editor. Emacs is more like an single thread operating system which runs as an editor. In order to explore the magic, we start from the basic extended configurations for the emacs.

Normally, emacs configuration files locate in directory ~/.emacs.d or ~/.emacs. The help information for Minor mode and Major mode can be explored by pressing key C-h m.

M-x package-list-packages lists all the packages can be installed.

Sevearl packages I installed in my personal emacs configuration file: auto-complete

Here is my initial configuration file for emacs:

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;;----------------------------------------
;;          Disable & Enable modes
;;----------------------------------------
;; Added by Package.el.  This must come before configurations of
;; installed packages.  Don't delete this line.  If you don't want it,
;; just comment it out by adding a semicolon to the start of the line.
;; You may delete these explanatory comments.
(require 'package)
(add-to-list 'package-archives '("melpa" . "http://melpa.milkbox.net/packages/"))
(package-initialize)
(global-linum-mode 1)
(tool-bar-mode -1)
;;----------------------------------------
;;          Emacs theme
;;----------------------------------------
(load-theme 'dracula t)
;;----------------------------------------
;;          Personal UI Setting
;;----------------------------------------
(setq cursor-type 'bar)
(setq inhibit-splash-screen 1)
;;----------------------------------------
;;          Font
;;----------------------------------------
(set-default-font "Monaco 16")
;;----------------------------------------
;;          New key binding
;;----------------------------------------
;;          open init file
;;----------------------------------------
(defun open-init-file ()
  (interactive)
  (find-file "~/.emacs.d/init.el"))
(global-set-key (kbd "<f1>") 'open-init-file)
;;----------------------------------------
;;          auto-complete
;;----------------------------------------
(custom-set-variables
 ;; custom-set-variables was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 '(package-selected-packages (quote (dracula-theme auto-complete))))
(custom-set-faces
 ;; custom-set-faces was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 )
(require 'auto-complete)
(require 'auto-complete-config)
(ac-config-default)

This will be extended in the future study.

Emacs lisp

Emacs lisp is a dialect of Lisp language family used for script language in Emacs. For the pragraming process, it has similar machanism with lisp or mit-scheme (another dialect of Lisp). Since emacs lisp (Elisp for short) functions as a script language inside Emacs, it is necessary to learn Elisp for deeper understanding of Emacs and further hacking purpose.

Inside the emacs, the lisp repl can be invoked by switching to *scratch* buffer. (C-x b searches for the specific buffer. Default buffer will be *scratch*)

While interacting with Elisp, we can use C-x C-e or C-j to compile our procedure.

A useful reference provides more details and basic knowledge about Elisp.

Reverse polish notation is used for number calculations in Elisp:

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(+ 2 2)
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(+ 2 (* 3 4))
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setq is used to create a new variable. insert is able to insert the string.

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(setq my-name "Yang")
"Yang"
(insert "Hello " my-name)

Here, when we input C-x C-e, the lisp will insert string Hello Yang in the following of the insertcommand.

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(insert "Hello " my-name)Hello Yang

defun can define a new function in the Elisp.

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(defun func () (insert "Hello"))
(func)

switch-to-buffer-other-window is used to create a new window with specific buffer.

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(switch-to-buffer-other-window "*test*") ;; switch to a buffer called *test*

progn combines multiple expressions into one expression.

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(progn
  (switch-to-buffer-other-window "*test*")
  (hello)
  (other-window 1))

let binds a value to a local variable.

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(let ((local-name "yang"))
     (hello local-name))

format is able to format a string with given format formula:

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(format "hello %s!\n" "visitor")

Of course, there are some interative commands like read-from-minibuffer:

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(read-from-minibuffer "Enter your name:")
;;; you can get variable name from prompt, such as
(defun greeting (from-name)
  (let ((your-name (read-from-minibuffer "Enter your name: ")))
    (insert (format "Hello!\n\nI am %s and you are %s."
                    from-name ; the argument of the function
                    your-name ; the let-bound var, entered at prompt
                    ))))
;;; evaluate this command
(greeting "Jack")

In this post, it just summaries the basic opeartions from the link mentioned in the first paragraph. More functions or data-structure operations can be discovered in the future code reading.

Emacas

I used to be a vim user for terminal coding. Not really a heavy user since I utilise Intellij for java development. But recently, I read the book called Structure and Interpretation of Computer Programs which explains the program in the deep level with Lisp. The path of Lisp learning arouses my interest Emacs, which provides EmacsLisp for functionality extension. As all we know, the Emacs is characterized by its extensibility.

Emacs stands for “the extensible, customizable, self-documenting, real-time display editor”. In order to try its special magic, the first step is to get familiar with its shortcuts.

Here is the summary for the common shortcuts listed in the emacs tutorial in Emacs (can be invoked by C-h t). A useful command is called C-h c + command to console the usage of the specific command. (For more detailed information, please use C-h k instead of C-h c)

C: stands for Control key. M: stands for Esc key.
Note, my development environment is based on mac laptop. M is replaced for Alt key on Windows computer.

Motion commands:

C-u is valid for any opeartions. Even for character inputs. i.e. C-u 8 will insert 8 in the editor.

Frame Operations:

Many opeartons starts with C-x. Most of them are related with windows, files, buffers opeartions.

The bottom line is called minibuffer.

Buffer Operations:

Emacs stores all file text into a object called buffer

Editor Operations:

In increment search mode, use C-s and <DEL> to move back / forward for matched results.

Welcome to My personal blog! This is literally my first post on my first blog. I am going to introduce how I build this blog.

Two major tools are used:

1. Hexo: a fast and simple blog framework. Very easy to develop and deploy personal blog, and it support markdown posts, which is my favorite note tool. Typora is recommended as a simple and clean markdown post editor.
2. NexT theme: personal preference, an elegant and clean Hexo theme.

Requirement

• Pre-downloaded Hexo repository

Construction

1. In your site/Hexo repo directory, download NexT theme.

   1 2	$ cd your-hexo-site $ git clone https://github.com/iissnan/hexo-theme-next themes/next

2. Configure NexT theme in Hexo directory. Apply NexT theme in _config.xml configuration file in root directory.

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   # Extensions ## Plugins: http://hexo.io/plugins/ ## Themes: http://hexo.io/themes/ # theme: landscape theme: next

   You can change different schemes based on your personal perference in _config.xml in theme directory. For example, scheme: Pisces can be applied in _config.xml file if you want to apply pisces scheme.

3. Learn how to develop and publish Github Pages in Github.

4. Generate static files and deploy your blog website to Github page.

   Configure deploy options in configuration file in root directory and use the following command.

   1	$ hexo deploy

5. Some other things like tag page or 404 page can also be set manually by following the official hexo guide.