Add HTML idioms to parse a list of whitespace-separated values

• Component: Layout and Rendering
• Status: NEW ---

[Frédéric Wang (:fredw)]

See bug 161045 comment 4 where this kind of idiom was needed to parse the menclose@notation attribute:

> The way I’d want to do this is to build a class that lets you iterate
> through a StringView in this fashion with a for loop. The way C++ for loops
> are written, we can make functions that return objects that use iterators
> like the way we do it in StringView::codeUnits(), although the function does
> not need to be a member of the StringView class. If we package it that way
> then we can write the main body of this as a simple for loop; the iterators
> need know nothing about addNotationFlags.
> 
> Could do one with isHTMLSpace built in, or one that takes a function as an
> argument.