Ask HN: Re-implementing an Open Source project in another language

bdfh42 · on March 31, 2009

This one is pretty simple. If you were to write a clone of (say) PhpBB without looking at the original source code but just re-engineering the functionality you wanted to replicate then you would have a new piece of software over which you could claim copyright and which you could license as you wish. This is just the same as sitting down to write (for example) a new word processing program that emulated key features of MS Word.

However, porting an existing GPL code base to a new language would I strongly suspect be seen as a simple "fork" of the original code and you would (quite rightly) have to release your new code under the GPL license. This is fair and just - you can't just rip off other peoples intellectual property no matter how much work there is involved in doing so.

jpcx01 · on March 31, 2009

Very useful answer. Thanks!

One quick clarification.. what if I reused CSS and Image Assets from PhpBB? Its sort of strange there because there are many templates that are under different licenses than the source code itself.

How does one define GPL on CSS and Images? They are open by default (since anyone can view source on a browser). I'm guessing this IP is governed under a different set of laws (copyright?).

SwellJoe · on March 31, 2009

They are open by default (since anyone can view source on a browser).

That doesn't make them "open" in the sense of Open Source or Free Software. It merely makes them open in the same way a book is open...you can read it, and you could even copy it without technical impediment, but it can still be a copyrighted work.

bdfh42 · on March 31, 2009

Getting more complex now you are into the detail. Partly, things depend upon the laws applicable in a given instance. In some cases copyright has to be explicitly claimed and in other jurisdictions it is implicit. This has been touched on at HN before - CSS code (and JavaScript, HTML etc) is effectively open in that it is generally available to be read by all but it may still be 'owned' in the sense that copyright will often still apply.

Perhaps one should apply a 'moral' filter. It seems OK (if not inevitable) for one's designs to be strongly influenced by the layout and colour schemes of existing sites but it also seems proper that one should not copy CSS and layouts wholesale from elsewhere. There are plenty of tutorial sites demonstrating the most complex of CSS code - copy from them where it encouraged and then apply your own unique 'spin'.

cjg · on March 31, 2009

It might also depend on the licence of the original project. For example, a project originally released under BSD could be re-released under many different kinds of licence.