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Date: Wed, 11 Feb 2015 13:37:10 +0100
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 Content preview:  Hi, On 2015-02-08 02:08, DJ Delorie wrote: > PCB's source
   is *ancient*. Even a simple clean-up pass would be a > large undertaking.
   It's probably one of the first examples of > object-oriented programming.
   [...] 
 
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Subject: Re: [geda-user] FOSDEM
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Hi,

On 2015-02-08 02:08, DJ Delorie wrote:

> PCB's source is *ancient*.  Even a simple clean-up pass would be a
> large undertaking.  It's probably one of the first examples of
> object-oriented programming.

Doing electronics is currently rather a hobby for me than my day to day 
work. I usually work as a web developer working with and developing the 
content management system TYPO3. I will try to put down some of my 
experience in there - maybe it makes sense for PCB also:

======

The CMS was created around the beginning of the millenia and since then 
got a lot of improvements. Especially during the last few years the 
complete core system got refacatored and parts got reimplemented to 
adhere to modern programming paradigms.

* They started with writing a bunch of units tests (units tests and 
functuional tests) for every thinkable code piece creating large code 
coverage.

* Then they introduced namespaces for every class (like in Java), split 
code up, removed duplicated code, etc.

* Unclear sections of code got documented, design patters were 
introduced (documented) where possible.


But in the meantime another group of people from the TYPO3 projcet 
started to create a whole new web framework (flow) + CMS (TYPO3 Neos). 
Like a second track. The framework itself was backported to TYPO3 CMS 
and parts of the core now rely on it - so they are tied together.

Some people were against a complete new start, others didn't like the 
old-school way how the product was created in the first place.

======

In the web-world there is a lot of common knowledge about what a 
CMS/web-framework needs to do, requires to have, etc. There needs to be 
a request dispatcher, a templating framework, a database abstraction, a 
persistence layer, domain models for every data structure, etc.

Maybe it would be a first start of refactoring PCB to define those 
requirements. If I would make a dummy-start I would create a list like:

* GUI Interface (human interface)
* Rendering engine (render the layout)
* DRC engine (enforce electrical rules)
* persistence layer (abstract data storage)
* plugin engine (i.e. for the autorouter)
* undo/redo logic
* etc.

Some time ago I started to read the famous "Design Patterns" book from 
the GoF [1]. Altough I got stuck on around page 90 I found the 
information very useful. The book describes most of the commonly found 
design patterns of software architecture, how to implement them properly 
and where they can be used.

Sadly the book focues on creating a new product rather than refactoring 
and cleaning up an old one.


[1] http://en.wikipedia.org/wiki/Design_Patterns
(wow. It even has its own wiki page :)

greetings,
Bernhard
-- 
Wer nicht gelegentlich auch einmal kausalwidrige Dinge zu denken vermag,
wird seine Wissenschaft nie um eine neue Idee bereichern können.
Max Planck (1858-1947)