enotepad

Clone of MS Notepad using Erlang (wxWidgets)

Motivation

In the process of learning Erlang, I wanted to make some GUI application, so I though I will make a Notepad clone, after all it is just a text control... it wasn't.

Things learned:

• how to use wxWidgets, wx_object and Scintilla
  • using menus, status bar
  • custom dialogs and simple dialogs
  • printing on a printer
• how to make a wxWidgets application using OTP design principles.
• how to build escripts and applications manually
• file handling, creating/removing directories
• dialyzer and types
• how to make releases with systools and with reltool

Requirement

• Erlang 19.1

Installation

This program is not inteded to be installed, its a learning tool.

Anyway, on Windows there is an installer, but for other systems you must build from source.

Building

This project uses an Emakefile and a custom escript to build, the idea behind it is to understand how things are build in Erlang. The command used is emaker and you can find it on the project root folder.

On windows run emaker help, on others ./emaker help.

available targets:
    all             - (default) runs make:all
    clean           - removes ebin
    rebuild         - cleans and build
    escript         - builds escript file for this system
    escript all     - builds escript file for all systems (not rebar style)
    escript windows - builds escript file for windows
    escript unix    - builds escript file for unix-like systems
    escript rebar   - builds escript file rebar style (windows file is small)
    escript exe     - same as 'escript rebar' but using .exe instead of .cmd
    dialyzer Type   - runs dializer, Type might be ebin(default) or src
    release systools- makes a release using systools
    release reltool - makes a release using reltool

For example emaker escript will build an escript version of enotepad, emaker release reltool will make a full release using reltool.

The output of emaker will be:

• ./ebin for normal build
• ./releases/escript for any of escript X
• ./releases/systool for release systools
• ./releases/reltool for release reltool

You could, if you so wish you can also run erl -make and will get the results on ebin.

Running

You can run enotepad in multiple ways: using Erlang shell, using the built escript and using a generated release.

Using Erlang shell

Within a project folder run erl -pa ebin then in the Erlang shell you have multiple options too, using main like the escript:

Eshell V8.1  (abort with ^G)
1> enotepad:main().
ok
2> enotepad:main(["some_file_name.txt"]).
ok

Using start_link which is used when running under supervisor, but you can use too:

Eshell V8.1  (abort with ^G)
1> enotepad:start_link().
ok
2> enotepad:start_link("some_file_name.txt").
ok

Starting like an application:

Eshell V8.1  (abort with ^G)
1> application:start(wx), application:start(enotepad).
ok
2> application:set_env(enotepad, file, "some_file_name.txt").
ok
3> application:start(enotepad).     <<-- this will load some_file_name.txt
ok

When running like an application, you can stop also with application:stop(enotepad) but this is not needed if you just close the window.

Using the escript

This way requires you to have a working installation of Erlang on the path, then just run it by name with optional parameter:

> path/to/enotepad <file_name>

Using a built release

This doesn't require Erlang as it already includes it, just run it by name like the escript, the actual file you run is a facade to hide the erl parameters.

@todo

Need to write a description of the knowledge acquired.