Yep, terminology in legal documents can be quite misleading when interpreted as colloquial language. Something to keep in mind when reading any Legalese.
On the contrary, legal documents are like code - you have to read them exactly as they are worded. They may use complex grammar and obscure vocabulary, but slow down, read every word and pretend it is code. There are no extra words, every "or" and "and" really is a boolean operator that impacts how to interpret a sentence.
If you are a coder, extracting an accurate meaning from legalese should come naturally. Just slow the flippety-flop down, stop trying to read it like a book, and instead read it like you are a compiler.
While there is a code-like aspect to reading legalese, the law isn't as specific as a programming language. No matter how hard you try, legal documents will have ambiguity.
I just read a case law week about whether "or" in a patent claim should be interpreted as OR or XOR.
I've been told by at least two patent lawyers that "and" and "or" are essentially synonymous. If you want to specify "xor" it's good to say "either a foo or a bar but not both a foo and a bar". But why be so specific? "One or both of a foo and a bar" could have broader coverage, presents the opportunity to mislead the competition, and (IANAL) seems to be just as sound even if "both" is actually infeasible.
Claim language such as "determining foo based on x, y, and y" is leaving the door open for a judge to interpret the limitation as requiring "x, y, AND z"
Better language (assuming it is how the thing works) is:
"determining foo based on one or more of x, y, or z"
The strange language in claims (and patents in general) is a response to litigation. Good patent prosecutors (the patent attorneys that draft patents) watch court cases and adjust their claim language accordingly.
Good patent litigators try to tear up or dissect the claim language (as well as everything else...). So patent prosecutors should draft with an eye toward litigation and include language that inoculates a patent from common or obvious attacks.
`every "or" and "and" really is a boolean operator'
In my experience, not being a lawyer, but working with people with legal educations on queries for document review, they didn't generally seem to "get" logical concepts like the idea that precedence of boolean operators matters to interpretation.
Maybe people who went to top tier law schools are better or something.
If you are a coder, extracting an accurate meaning from legalese should come naturally. Just slow the flippety-flop down, stop trying to read it like a book, and instead read it like you are a compiler.