Legal/Permission Question

[David B. Held]

Dan wrote:
> Considering that my Walnut 2.x engine performs much the same functionality as DMDScript, but that Walnut 2.x is written significantly differently on a structural level...
> 
> DMDScript is a GPL v1 engine, and Walnut 2.x is a new BSD engine.
> 
> When I fill in the function stubs for, for example, Number_prototype_toFixed, am I allowed to examine Walter's DMDScript source code, write something similar (but obviously not the same) and still call it new BSD?
> 
> What requirements are there to do such a thing?

Generally, the best way to implement something that someone else has 
written is to use a "clean room" technique where you isolate yourself 
from any possible external influences, as Walter and others have pointed 
out.  Even if you are clever enough to change or obfuscate all the 
identifiers, people are hard at working creating similarity programs 
that detect likeness without any exact matches.

On the one hand, you probably don't have to worry about Walter hunting 
you down with lawyers, because he knows you can't squeeze blood from a 
turnip.  On the other, if your library becomes as successful as you hope 
it does and DMDScript gets bought out by a SCO-like player, then you 
have a world of hurt coming your way.

Take a look at http://en.wikipedia.org/wiki/Clean_room_design and keep 
in mind that while the clean room technique may be a defense against 
copyright infringement, it is not a defense against patents (not sure if 
Walter has any patents on any D stuff, or if anyone does, but this seems 
like the smaller risk for you).  The fact that you are already part of 
the D community may strongly imply that you are already tainted.

Good luck.

Dave