[Tagging] Reviving the conditions debate

[Eckhart Wörner]

Hi Colin,

Am Freitag, 15. Juni 2012, 00:24:18 schrieb Colin Smale:
> "If I were king" I would be looking for a system that:
> * makes common cases easy

Extended conditions: ☑

> * makes complex cases possible

Extended conditions: ☑

> * makes each rule as standalone as possible (one sign -> one rule)

Extended conditions: ☑

> * does not rely on the user's fluency in English grammar (knowledge of a 
> set of specific words, e.g. tags and functions, is fine)

Extended conditions: ☑

> * uses grammatical constructions which are familiar to most people, or 
> easily learnt

Extended conditions: ☑

> * has a grammar allowing for a user-extensible function repertoire

Extended conditions: ☑

> * allowing user-defined functions to be stored in an external file 
> (accessible at entry and run time)

I'm not sure I get that one, but it sounds to me like you're trying to mix specification and implementation, which is just a bad idea.

> * fits comfortably with the key-value-pair paradigm of OSM

Extended conditions: ☑

> * can produce a result in a variety of data types including at least 
> boolean, number, string

Please provide a use case.

> * can use the value of other tags as variables

That's just a desaster waiting to happen.

> * can use other variables supplied at run time (e.g. weather, time, 
> vehicle type)

Extended conditions: ☑

> * supports the usual comparision and numeric operations

Which "usual" comparison operations? '12 knots' < '35 mph' ?

> * supports string concatenation operation

name = (lang == 'de' ? 'Bahnhof von ' : 'Gare de ') + 'Lyon'
Please provide a use case.

Eckhart