I am not familiar with the literature on scanners. May I ask you about some details on the "for all characters" algorithms you are referring to?
Building a (or connecting to) a BDD library would be fun, indeed. But within that time frame it seems not realistic. Anyway, after finishing my thesis, I'd like to come back to that idea. Ciao, Steffen Am 7. November 2017 16:33:03 MEZ schrieb Andrew Glynn <aglyn...@gmail.com>: >A possible way to accomplish it would be to use an object graph with an >incremental query engine, such as EMF/CDO with Viatra or something >similar. You could then put different character sets in connected >objects and query only as far as you need to. > >Andrew Glynn > >Sent from Mail for Windows 10 > >From: Thierry Goubier >Sent: Tuesday, November 7, 2017 7:17 AM >To: Any question about pharo is welcome >Subject: Re: [Pharo-users] Binary Decision Diagram Package in Smalltalk > >Hi Andrew, Steffen, > >2017-11-07 13:10 GMT+01:00 Prof. Andrew P. Black <bl...@cs.pdx.edu>: > >> On 28 Oct 2017, at 17:37 , Steffen Märcker <merk...@web.de> wrote: >> >> Does that mean the sets/bdd would be constructed mainly at comile >time? Anyway, Andrew, feel free to contact me, I might help you with >this. >> > >Thanks for the offer, Steffen! The problem is that I need to use SmaCC >for my current project, and really do not have a month to take off and >re-design the way that it builds its scanner. I’ve talked to Thierry >Goubier about, and he doesn’t have time either! It would be a fun >project, though, and it ought to be fairly separate from other parts of >SmaCC. I’ve spent a fair bit of time thinking about how to do it, but >don’t think that I will be able to actually focus on it. > >Yes, this is the essence of the issue. There are a few alternatives >about it, but none we have the time to pursue. > > >An alternative approach, which Thierry has suggested, is to make SmaCC >work on the UTF-8 representation of the Unicode. Then we could >represent character sets as prefix trees. But the core problem would >still exist: you can’t run an algorithm that repeatedly executes > > for all characters in the alphabet do: > >when there are 2^21 characters in the alphabet! > >The main issue is that `for all characters`... All the literature on >scanner building uses 'for all characters do'. > >Thierry > > > Andrew
