.
How often is this actually used?
Shoudn't it be called "deleted text", as the exact presentation depends on the style?
What are the use cases where this is actually required?
The proposed markup collides with the traditional use of "--" to mean a dash, and with the traditional signatures -- so it's not CollisionFree.
-- RadomirDopieralski, 2006-12-15
Agreed. It's useful in blog-like applications, but in a wiki it's just easier to delete the text. I see no real use case for this, and it only serves to confuse people.
Actually this is CollisionFree. TiddlyWiki uses "--" to mean mdash and also uses --strike-- formatting. The formatter distinguishes between a freestanding "--" and "--" wrapping a word or phrase. This is fairly straightforward to implement (I know, because I implemented it for TiddlyWiki).
-- MartinBudden, 2006-12-17
Not everyone puts spaces around dashes and signatures -- it is the current recommendation for modern typography, but some people follow old style or like to experiment. Also note how this looks in the raw page text -- as if someone inteded to insert a word surrounded by dashes, just didn't make the spaces. But this is a minor issue, and indeed there is a million ways to solve that.
The fundamental issue is "Do we need it hard enough to make Creole more complicated"?
Another concern about it being CollissionFree -- looking at the markup summaries on Wikimatrix I see that engines use "--" and "~" interchangeably. So, no matter which one we choose for "deleted text", we will introduce a conflict with some of the existing markups. -- RadomirDopieralski, 2006-12-18
I agree, we should keep creole simple, but not simpler of course :). It should be possible to describe creole on a single cheet sheet. I never missed this markup in jspwiki. I would't count it to the common things people need. You still can use native markup in a mixed mode to do it. Maybe we could have some standard extentions for creole in the future, but i think it's to early now.
-- Christoph, 2006-12-19