On Tue, Sep 23, 2014 at 1:10 PM, Udo Schneider <udo.schneider@homeaddress.de> wrote:

> 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.
I normally encounter two issues with RegExps:

1) The syntax between different apps/libs/frameworks differs sligtly. Esp. for character classes or greediness. This drove me crazy more than one time.
2) Often enough I realize (while developing the RegExp) that I need something more capable than a Chomsky Type 3 parser (which RegExps are in a way). So I have to use "a bigger gun" - e.g. PetitParser.

CU,

Udo

On 23.09.14 10:15, kilon alios wrote:

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.schneider@homeaddress.de
<mailto:udo.schneider@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.schneider@homeaddress.de
�� <mailto:udo.schneider@homeaddress.de>
�� <mailto:udo.schneider@__homeaddress.de

�� <mailto:udo.schneider@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.schneider@homeaddress.de
�� <mailto:udo.schneider@homeaddress.de>
�� <mailto:udo.schneider@__homeaddress.de
�� <mailto:udo.schneider@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.__blo__gspot.de/2014/09/block-____translators-parsing-magic.html
�� <http://blogspot.de/2014/09/block-__translators-parsing-magic.html>

�� <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