Re: [9fans] non greedy regular expressions

[erik quanstrom <quanstro@coraid.com>]

> Ok, so despite the documentation, some submatch tracking is there.
> But in all (?) your examples, as well as in the scripts you mentioned,
> this tracking is exclusively used with the s command (which is said to
> be unnecessary at least in sam/acme). If I try sth. like
> /( b(.)b)/a/\1\2/

this is covered in the sam paper in the section where pike
discusses s.

> Further, in R. Cox's text (http://swtch.com/~rsc/regexp/regexp1.html)
> he claims that all nice features except for backreferences can be
> implemented with Thomson's NFA algorithm. And even the backreferences
> can be handled gracefully somehow. That is: ALL: non-greedy operators,
> generalized assertions, counted repetitions, character classes CAN be
> processed using the fast algorithm. Why then we don't have it?

let me turn this around.  why would these additions (complications)
benefit plan 9?

- erik