it reminds a lot of Kent's Beck Smalltalk Practice Patterns where it removes all ifs and replaces them with regular unary messages . It is definitely an elegant way of coding making the code just flow.
I have not used PettitParser yet, looks powerful but I find it a bit weird in design. On the other hand regex is quite ugly and understanding complex regex a pain. On Tue, Sep 23, 2014 at 11:07 AM, Udo Schneider < udo.schnei...@homeaddress.de> wrote: > > just as it is black magic for me now :D > The nice thing about this approach is the fact that it "just" piggybacks > the normal Smalltalk message sending. So you can step through it using the > Debugger - it's Smalltalk all the way down. > > I still remember my first shock when (having no formal background on > parsing theory at that time) I saw the parsing tables generated by T-Gen. > Of course it was Smalltalk ... but understanding those tables was a > nightmare. > > PetitParser is the gold standard here IMHO. It is able to parse arbitrary > input (compared to my block expressions only). And you can still use the > Debugger to step through the parsing process *and still understand what's > going on!* > > CU, > > Udo > > On 23.09.14 09:54, kilon alios wrote: > >> just as it is black magic for me now :D >> >> At least I get the general feeling. I am new to parsing too, so far I >> have only played with regex parsing. Not the most smalltalkish way but >> it works well so far. >> >> On Tue, Sep 23, 2014 at 9:39 AM, Udo Schneider >> <udo.schnei...@homeaddress.de >> <mailto:udo.schnei...@homeaddress.de>> wrote: >> >> Hi Estaban, >> >> I think the first time I saw this pattern was in ReStore on Dolphin >> Smalltalk. I didn't understand it's implementation back then. I >> assume that it's similar to what I described though. But having a >> Smalltalk block automagically creating the equivalent SQL SELECT >> expression was like black magic at that time :-) >> >> CU, >> >> Udo >> >> >> >> >> On 23.09.14 04:15, Esteban A. Maringolo wrote: >> >> Excellent article. >> >> I think GLORP uses a similar technique to setup its expressions, >> and >> also have issues with #and:/#or: selectors due to inlining, so >> it uses >> AND:/#OR: instead. >> >> Regards! >> >> Esteban A. Maringolo >> >> pd: Your blog and it's choosen topic made me remember >> http://use-the-index-luke.com/ >> >> 2014-09-22 20:48 GMT-03:00 Udo Schneider >> <udo.schnei...@homeaddress.de >> <mailto:udo.schnei...@homeaddress.de>>__: >> >> >> All, >> >> I just finished a blog entry. It shows how to use Smalltalk >> blocks as parsers/translators. E.g. translating a Block >> >> [:customer | (customer joinDate year is: Date >> today year)] >> >> into an SQL-like String >> >> (YEAR(customers.joinDate) = 2014) >> >> The SQL stuff is just an example - you can create nearly any >> output. >> >> Check out >> http://readthesourceluke.__blogspot.de/2014/09/block-__ >> translators-parsing-magic.html >> <http://readthesourceluke.blogspot.de/2014/09/block- >> translators-parsing-magic.html> >> >> Maybe that's old stuff for some of you - but I hope it's >> interesting for some at least :-) >> >> Comments and feedback appreciated. >> >> CU, >> >> Udo >> >> >> >> >> >> >> >> >> > > >
