Entries posted in July 2016

A final post about the lua-editor.

Saturday, 23 July 2016

I recently mentioned that I'd forked Antirez's editor and added lua to it.

I've been working on it, on and off, for the past week or two now. It's finally reached a point where I'm content:

  • The undo-support is improved.
  • It has buffers, such that you can open multiple files and switch between them.
    • This allows this to work "kilua *.txt", for example.
  • The syntax-highlighting is improved.
    • We can now change the size of TAB-characters.
    • We can now enable/disable highlighting of trailing whitespace.
  • The default configuration-file is now embedded in the body of the editor, so you can run it portably.
  • The keyboard input is better, allowing multi-character bindings.
    • The following are possible, for example ^C, M-!, ^X^C, etc.

Most of the obvious things I use in Emacs are present, such as the ability to customize the status-bar (right now it shows the cursor position, the number of characters, the number of words, etc, etc).

Anyway I'll stop talking about it now :)

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Adding lua to all the things!

Thursday, 14 July 2016

Recently Antirez made a post documenting a simple editor in 1k of pure C, the post was interesting in itself, and the editor is a cute toy because it doesn't use curses - instead using escape sequences.

The github project became very popular and much interesting discussion took place on hacker news.

My interest was piqued because I've obviously spent a few months working on my own console based program, and so I had to read the code, see what I could learn, and generally have some fun.

As expected Salvatore's code is refreshingly simple, neat in some areas, terse in others, but always a pleasure to read.

Also, as expected, a number of forks appeared adding various features. I figured I could do the same, so I did the obvious thing in adding Lua scripting support to the project. In my fork the core of the editor is mostly left alone, instead code was moved out of it into an external lua script.

The highlight of my lua code is this magic:

  --
  -- Keymap of bound keys
  --
  local keymap = {}

  --
  --  Default bindings
  --
  keymap['^A']        = sol
  keymap['^D']        = function() insert( os.date() ) end
  keymap['^E']        = eol
  keymap['^H']        = delete
  keymap['^L']        = eval
  keymap['^M']        = function() insert("\n") end

I wrote a function invoked on every key-press, and use that to lookup key-bindings. By adding a bunch of primitives to export/manipulate the core of the editor from Lua I simplified the editor's core logic, and allowed interesting facilities:

  • Interactive evaluation of lua.
  • The ability to remap keys on the fly.
  • The ability to insert command output into the buffer.
  • The implementation of copy/past entirely in Lua_.

All in all I had fun, and I continue to think a Lua-scripted editor would be a neat project - I'm just not sure there's a "market" for another editor.

View my fork here, and see the sample kilo.lua config file.

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I've been moving and updating websites.

Friday, 8 July 2016

I've spent the past days updating several of my websites to be "responsive". Mostly that means I open the site in firefox then press Ctrl-alt-m to switch to mobile-view. Once I have the mobile-view I then fix the site to look good in small small space.

Because my general design skills are poor I've been fixing most sites by moving to bootstrap, and ensuring that I don't use headers/footers that are fixed-position.

Beyond the fixes to appearances I've also started rationalizing the domains, migrating content across to new homes. I've got a provisional theme setup at steve.fi, and I've moved my blog over there too.

The plan for blog-migration went well:

  • Setup a redirect to from https://blog.steve.org.uk to https://blog.steve.fi/
  • Replace the old feed with a CGI script which outputs one post a day, telling visitors to update their feed.
    • This just generates one post, but the UUID of the post has the current date in it. That means it will always be fresh, and always be visible.
  • Updated the template/layout on the new site to use bootstrap.

The plan was originally to setup a HTTP-redirect, but I realized that this would mean I'd need to keep the redirect in-place forever, as visitors would have no incentive to fix their links, or update their feeds.

By adding the fake-RSS-feed, pointing to the new location, I am able to assume that eventually people will update, and I can drop the dns record for blog.steve.org.uk entirely - Already google seems to have updated its spidering and searching shows the new domain already.

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