[erlang-questions] A PropEr announcement

James Churchman <>
Fri Jun 17 12:43:51 CEST 2011


making something with a similar-ish api to something else is not reverse engineering. its a rewrite from scratch. reverse engineering would be disassembling the beam files to discover how they work, simply reimplementing them it is not. if that was the case there would be one cd player, one car, one bike, one washing machine, one fridge, one operating system etc.. in the world and never ever a second version, and having a copy of the original will make no difference, if you clean room something, as long as you don't break any patents in the process.

On 17 Jun 2011, at 04:30, Edmond Begumisa wrote:

> On Fri, 17 Jun 2011 12:56:59 +1000, Edmond Begumisa <> wrote:
> 
>> Just to clarify/reinforce, what gets a little confusing in these discussions are the rights and obligations between licensor and licensee, which is a contractual arrangement and subject to the doctrine of privity.
>> 
> 
> CORRECTION: This was inaccurate. A licensee agreement is not strictly contractual agreement, but a license may be passed as consideration exchanged as part of a contractual agreement. Nevertheless, the privy doctrine usually applies to agreements in which licenses are past in most jurisdictions.
> 
>> [Continuing with the mentioned hypothetical]
>> 
>> * If the PropEr developers have copies of QuickCheck Mini, then they bind themselves to a license agreement with Quviq, including the promise not to reverse engineer.
>> * If PropEr is GPL'ed, and Vlad uses it, he binds himself to an agreement with the PropEr developers, and the terms thereunder.
>> 
>> Vlad is not privy to the first agreement, and thus can never be held liable for its breach, if there is such a breach. And he cannot be expected to stop using a version he already has. (Though he might have the rug pulled out from under him, should PropEr development cease and future versions stop being made.)
>> 
>> However, assuming all parties are in Europe, and although the concept of freedom of contract generally applies, they also bind themselves doctrine that they can never make an agreement that contravenes codified EU law - including said reverse-engineering law in said copyright statute. Then the aggrieved party need not be privy to an agreement to have their rights enforced since these rights are not established by an agreement, but by a statute. In this case, Vlad and all PropEr users in Europe could well be ordered by a court to cease using the program regardless of any agreement they have with it's developers (since such an agreement would be considered invalidated.) Hypothetically speaking.
>> 
>> That said: Erlang being a small-friendly community -- I assumed (and like to continue to a assume) that PropEr and QuickCheck developers have not only been aware of each others projects, but I also like to think that they've been in touch with each other and sorted out any such concerns before version 1 of PropEr was announced. Like Erlang, I prefer to think of the happy case!
>> 
>> - Edmond -
>> 
>> 
>> On Thu, 16 Jun 2011 18:23:04 +1000, Ulf Wiger <> wrote:
>> 
>>> 
>>> On 16 Jun 2011, at 10:01, Vlad Dumitrescu wrote:
>>> 
>>>> On Thu, Jun 16, 2011 at 08:43, Ulf Wiger <> wrote:
>>>> 
>>>> On 16 Jun 2011, at 08:30, Vlad Dumitrescu wrote:
>>>> 
>>>>> Hi,
>>>>> 
>>>>> This kind of issues are worse than flame wars! :-)
>>>>> 
>>>>> I have yet another point of view that increases the confusion: PropEr is mostly compatible with Triq and QuickCheck (there's a free older version).
>>>> 
>>>> Well, there is a version available in jungerl, but to my knowledge, it was not put there by the authors, and not actually intended to be free. Even so, one might consider it a lot less sensitive to copy that version than the later, proprietary, versions of QuickCheck.
>>>> 
>>>> Quviq released an official mini-version last year.
>>>> 
>>>> http://www.quviq.com/news100621.html
>>> 
>>> Yes, but the QuickCheck Mini license agreement, while permitting free use and re-distribution, specifically forbids reverse-engineering. Thus, we should hope that the PropEr developers did not obtain a copy of QuickCheck Mini and ran it in order to learn how it worked, as this would put them in violation of the EU Directives regarding software copyright.
>>> 
>>> For those who are inspired by PropEr, but are put off by the GPL, using and re-distributing QuickCheck Mini is of course unproblematic. ;-)
>>> 
>>> BR,
>>> Ulf W
>>> 
>>> Ulf Wiger, CTO, Erlang Solutions, Ltd.
>>> http://erlang-solutions.com
>>> 
>>> 
>>> 
>> 
>> 
> 
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