You have to write R2L parsing logic anyway, because it's what you want most of the time (e.g. "div span a.quote"). Yes, in the special case where #uniq identifi

You have to write R2L parsing logic anyway, because it's what you want most of the time (e.g. "div span a.quote"). Yes, in the special case where #uniq identifiers are used and you know the page to be valid (X)HTML and you know that you get a substantial speedup by filtering on the #uniq node first L2R parsing is preferable. But how realistic is that, really? Isn't it just easier to teach web developers to write their DOM selectors in a specific way? The R2L approach is (a) easy to understand (b) has predictable (and stable) performance (c) doesn't malloc (d) is easy to implement. I see this as a simple case of "good enough".