Talk:Any tags you like

Section "Syntactic conventions for new tags"

Right to put this here? There are some proposals in the air right now that introduce or make use of Yet Another Separator for the key part, and I thought it might be generally useful if people knew/documented what possible interpretations of a complex key already exist. Not that there are any really formal ones yet, of course.

Do people basically agree with the explanation, BTW? It's sort of what I've been using in the past, and what I've inferred from what other people do. Might be incorrect, but hey: one person on IRC seconded what I wrote... --achadwick 21:34, 1 January 2009 (UTC)

Yeah in general whenever I see proposals for tags with ':' separators (or worse, other new separator ideas), it's people who are thinking about it so much that they've lost sight of the main thing. The number one priority here: keeping editing simple for beginners. The community has a long tail shape. Every time we jack up the complexity, even slightly, that's thousands of new users who are put off editing. The page does make the KISS point. Looks good. -- Harry Wood 11:33, 22 September 2010 (BST)

Perhaps it could be separated out into a linked page, maybe with or alongside some blurb about semantics. At the very least, being able to link in proposal discussions to some vaguely well-established explanations of what kinds of things should go in tags keys, why to keep it the syntax simple, and what "all those tags on an object" mean together might help prevent some syntactically ugly or semantically broken schemes - and patterns of tagging that deploy their use in a widespread way - from emerging. --achadwick 16:21, 15 June 2011 (BST)

Semantics

Perhaps a few notes on tagging semantics should go somewhere, as a guide for the lost. Though I don't know whether we should be saying much more than

1. Each tag on an object makes a true statement. A tag such as food=no means that food is not served here, but it's still a true statement despite being expressed negatively.
2. All such statements in the object's set of tags are true together. In terms of Boolean logic, they're ANDed together.
   • This means that tagsets should never make directly conflicting statements; otherwise software will become upset. Consider the original proposal for disused=yes, which interferes with every tag describing the object's current use if you're not careful.
3. A new tag on an object may refine the meaning of a previous tag, but may never contradict it, as above.
4. Sometimes tags imply things about physical properties or the services offered by an object. You don't have to be able to express an implication as a tag — tagging is quite a loose art, and implications sometimes vary by country — but if you can, you may override such implicit meaning.
   • For example, an object tagged amenity=pub might be said to imply that it may serve food (or might not). Adding food=no clarifies and refines this. It's even OK to contradict or override something that might be implied by another tag, but all explicit statements made by a tagset must always be internally consistent.

I hope that make sense. Are there any widely deployed tagging schemes that make internally-inconsistent statements out there? --achadwick 16:43, 15 June 2011 (BST)