Hacker News Reader

Comment by 0cf8612b2e1e | Hacker News Reader

  The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted exactly as how much we do not want to review your generated submission.

I know it is in jest, but I really hate that so many documents include “shall”. The interpretation of which has had official legal rulings going both ways.

You MUST use less ambiguous language and default to “MUST” or “SHOULD”

View on HN

Around 1990 I attended ISO/JTC1 meetings generating standards for data communication. I still recall my surprise over the heated arguments over these words between the UK and the US delegations. (I'm from Denmark). In particular 'shall' and 'should' meant different things in English and American languages. ISO's first standard, ISO 1, states that ISO Standards shall be written in English so we had to do that, US delegation too. Similarly Scott Bradner stated in RFC 2219 how American conventions should be followed for future IETF STDs.

So I'm confident that the word 'shall' has a strong meaning in English; whether it has too in American legalese I cannot tell.

Not a lawyer, but I have heard of a few American legal cases where the judge had to decide the meaning of a “shall”, so it does not seem well settled from my vantage.

On (possibly weak) counterpoint that I can offer is that in some languages, “must not” is a false friend, easily misinterpreted as “is not required to” (“it is not the case that they must”).

Right. I think when these appear in some documentation related to computing, they should also mention whether it is using these words in compliance with RFC 2119 or RFC 6919.

Must is a strict requirement, no flexibility. Shall is a recommendation or a duty, you should do it. You must put gas in the car to drive it. You shall get an oil change every 6000 miles.

Well then you MUST reread RFC 2119, because your version of SHALL differs from the spec which says SHALL is equivalent to MUST and a hard requirement.

Perfectly making my point. Shall has no business being in a spec when you have unambiguous alternatives.

Many legal documents use "may" to say you must. That's why i hate legalese...

Hmm, that's annoying, I'd take may as "CAN"

"may only" and "may not", however, are unambiguously hard limits, which makes things even more confusing.

"may only" means your pleasure is limited only to what options the agreement allows, which is a polite way of saying can not.

I don't know what terrible lawyers were hired to draft these "many" documents, but please share some examples.

Legal documents use "may" to allow for something. Usually it only needs to be allowed so that it can happen. So I read terms of service and privacy policies like all "may" is "will". "Your data may (will) be shared with (sold to) one or more of (all of) our data processing partners. You may (will) be asked (demanded) to provide identity verification, which may (will) include (but is not limited to) [everything on your passport]." And so on.

Reply on news.ycombinator.com