cells-devel May 2005

cells-devel@common-lisp.net

8 participants
23 discussions

[cells-devel] Re: [cells-gtk-devel] New cells-gtk capabilities and new tarball
by Kenny Tilton 31 May '05

31 May '05

Peter Denno wrote: >>I was over on 6.2 because Cells-Gtk had worked there, >>and under ACL7 I was getting an obscure error loading the GTK dlls. I >>have not touched those since playing with cgtk, so I thought maybe the >>ACL loader was doing something different. Nope, same error on ACL 6.2. >>So as usual with Windows, nothing makes sense and I am slowly installing >>the latest GTK+ 2.6.7 family of libs to see if I can get Gtk working >>itself. >> >>If that succeeds, I will then finish a little libgtkcells VC++ project >>to build a win32 dll for that and see if I can get the new stuff working. >> >> > >I'd be real interested in knowing how that goes. > The error persists.Loading libgobject, libintl_bind_textdomain_codeset not found in intl.dll. libintl.h shows that as a valid exported label. That is under ACL7. I am trying also from Lispworks Trial, but that seems to be unhappy with the logical-pathname usage in load.lisp: ASDF reports it cannot find Cells. Anyone have a clue on the INTL issue? I did a fresh install of GIMP, which brings down all the gtk stuff. And the GIMP app itself runs fine. kenny

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[cells-devel] Thought For Someone Who Would Use Cells to Do Prolog
by Kenny Tilton 31 May '05

31 May '05

If your Prolog-in-CL uses slot readers/accessors, dependencies will arise. So the position (or whatever GUI layout attribute you have in mind) can be calculated by a cl-prolog operating over CLOS instances via CLOS slot accessor GFs, and the necessary dataflow will arise naturally. The invocation of the cl-prolog computation will have to require dynamic insertion of initializing/configuring facts. The cell rule calculating the result will specify these facts from other cell values, and supply the calculating form. This then neatly embeds Prolog within Cells, with the Prolog both driving and driven by Cells. Yet one gets (I presume) the greater performance from a dedicated prolog working on a fixed set of facts (for the duration of a single calculation). Not very sure of the above, btw. kenny -- Cells? : http://www.common-lisp.net/project/cells/ Cello? : http://www.common-lisp.net/project/cello/ Cells-Gtk? : http://www.common-lisp.net/project/cells-gtk/ Why Lisp? http://lisp.tech.coop/RtL%20Highlight%20Film "Doctor, I wrestled with reality for forty years, and I am happy to state that I finally won out over it." -- Elwood P. Dowd

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[Fwd: Re: [cells-devel] Logic Programming in Cells]
by Kenny Tilton 26 May '05

26 May '05

-------- Original Message -------- Subject: Re: [cells-devel] Logic Programming in Cells Date: Tue, 24 May 2005 12:37:50 -0400 From: Kenny Tilton <ktilton(a)nyc.rr.com> To: Thomas F. Burdick <tfb(a)OCF.Berkeley.EDU> References: <17043.19525.48820.752685(a)conquest.OCF.Berkeley.EDU> Thomas F. Burdick wrote: >I was looking to build a Prolog-ish logic-programming layer on top of >Cells, and looking at how to do this, it looks like basic support >could be added to Cells itself pretty easily. Here's what I'm >thinking. We add a new type of Cell, let's call it a Generator. Data >propogation proceeds as usual, but when we get to a Generator, we mark >this on a stack. If evaluation of some formula calls FAIL, we go back >to the last Generator, evaluate it again, and resume data propogation >from there. Any pending inputs from code that was backtracked over >would of course be thrown out. > >Any thoughts? > So the generator sits there trying different values, with nested generators each working thru their values? The generator needs to be able to keep track of where it is between evaluations, including knowing when it is starting a fresh search (if you will). Are you up to speed on the new propagation scheme, as featured most prominently in "unfinished-business"? I guess teh good news is that propagation to dependent cells completes before any output is done, so you do not have to back out outputs (and rules are not supposed to have side effects, tho I did just that in the Dwo Jones use case <gasp>.). But what about the dependency propagation itself? A retry by the Generator may not propagate to the same population, so some positive mechanism must un-calculate dependencies reached during any failed propagation. Too bad I am not using the stack any more....Just had an idea. I need to look at the logic again, but what if we let dependency propagation take place on the stack. One nice thing here is that I was just about to /fake/ a stack just for debugging purposes, so I could figure out where problematic data pulses were originating. So either we do not need to do that, or that supports the backtracking you will need. Again, have you been thinking about these issues? Either way, am I in the right ballpark approach-wise? kt -- Cells? Cello?: http://www.common-lisp.net/project/cells/ Cells-Gtk?: http://www.common-lisp.net/project/cells-gtk/ Why Lisp? http://lisp.tech.coop/RtL%20Highlight%20Film "Doctor, I wrestled with reality for forty years, and I am happy to state that I finally won out over it." -- Elwood P. Dowd

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[cells-devel] *causation*
by Kenny Tilton 26 May '05

26 May '05

It's back. *causation* is now bound to a "stack" of propagating cells, where the last element of the list is the original cause. Of course, to achieve proper backout this really needs to become more history than stack, because propagation sweeps a tree of dependencies, and the FAIL even can arise in a second branch of propagation, at which point a stack will have lost track of the first branch of propagation. Over to you, Prolog fans. kenny

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[cells-devel] Hooks on Cells accesses?
by Frank Goenninger DG1SBG 25 May '05

25 May '05

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Dear Cells Users: Maybe you have come across this also ... While working on the other challenges I have been telling on this list I am also trying to set-up an authorization model for Cells. I need to check permissions to Create, Update, Read, and Delete a cell slot. I thought about having hooks on each of these operations such that on every such operation within Cells an "outside function" can be called. These just return t or nil depending on permission check success or failure. As the model outside can be quite different from case to case (app to app) I did not think about implementing this within Cells. So (cells:add-hook 'cells:slot-read slot-reference 'my-permission-check- function) would install that hook. Or should I keep this on class level instead of on slot level because of possible impacts on propagation speed and other inner Cells aspects? I'd prefer to get the fine-grained control here and no, I'm not trying to get into the premature optimization game but want to get some basic thoughts straight. Again: Any feedback very welcome! Cheers, Frank -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (Darwin) iEYEARECAAYFAkKTcTEACgkQfYXhf9DGKdbaowCfXXtDJ61h9xQUMjkzarsh84f+ hl4AoLNk1dS2C56Slb6VRuYZdL0mvYuV =iwCb -----END PGP SIGNATURE-----

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[cells-devel] Cello migration underway
by Kenny Tilton 25 May '05

25 May '05

Anyone interested in Cello should know that I am slowly moving code from subdirectories under the cell-cultures module of Cells to their own modules under the Cello project. The module status is earned by being something which, if successful, could rightly be its own c-l.net project. I do not want to take that ambitious step since I am leaning towards hosting all future development on my own site (does not exist yet). So far I have moved hello-c and cl-opengl to the Cello project. kt

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[cells-devel] Logic Programming in Cells
by Thomas F. Burdick 24 May '05

24 May '05

I was looking to build a Prolog-ish logic-programming layer on top of Cells, and looking at how to do this, it looks like basic support could be added to Cells itself pretty easily. Here's what I'm thinking. We add a new type of Cell, let's call it a Generator. Data propogation proceeds as usual, but when we get to a Generator, we mark this on a stack. If evaluation of some formula calls FAIL, we go back to the last Generator, evaluate it again, and resume data propogation from there. Any pending inputs from code that was backtracked over would of course be thrown out. Any thoughts? It's a holiday here on thursday, so I'm thinking about hacking on this then.

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[cells-devel] Meta-level oof relations ... How?
by Frank Goenninger DG1SBG 24 May '05

24 May '05

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 To all: This is the beginning of a discussion about what I called meta-level usage of the Cells approach and mechanism actually using Kenny's Cells package. You better start at the bottom to get this straight then go up again and read downwards <g> Here we go: Am 24.05.2005 um 00:30 schrieb Kenny Tilton: > Frank Goenninger - PRION Consulting wrote: > >> Kenny, >> >> while designing my app here I am stuck with the following problem: >> >> Using Cells I want to build an object management kernel (to be >> used within my Product Information Management Application). This >> kernel has to implement a basic set of operations to manage >> objects (instances of any kind of class) such as Create, Read, >> Update (using Check-in / Check-Out into / from Vaults) and such. >> >> While Cells is perfect for modeling dependencies between instances >> of objects (using synapses) I am now about to implement relations >> and dependencies between classes. > > uh-oh, maybe Thomas is right and "synapses" is as confusing as it > is clever. And synapses are now just Cells, to make things even > worse. :) But I still talk about synapses as a class. Cells model > dataflow from one slot of an instance to another slot of the same > or different instance. That is, a c-ruled (or is it c-dependent?) > can access any combination of other c-ruled or c-input cells. A > synapse arises where one wants either to (a) mediate that > dependency, say with an f-sensitivity synapse; (b) translate the > dataflow, as with a delta synapse; or (c) do either with an > arbitrary subform within a cell rule (something I might have > pointed out with the new Synapse mechanism, and will shortly in a > standalone post). I think it is worth here to distinguish between two separate domains where the terms CLASS, INSTANCE, RELATION, DEPENDENCY each have different meanings and side effects. In the Application domain (my app being based on Cells) has Classes that get defined while adapting the app to a user's needs. A typical class would be "BOM" (said bill of material). The other one to be use in the use case outlined below is class "PART". So we have: + Application Class BOM + Application Class PART + Class Relation IS-USED-IN: PART -> BOM (read: a PART can be related to a BOM with the relation IS-USED-IN). This is a relation defined on CLASS (!) level. + Instance "As Built BOM, Baseline 001" of application class BOM + Instance "High Pressure Turbine, Serial Nr 0001" of class PART In order to make the use case more verbose we define some attributes on the classes: + Attribute PRICE on class BOM + Attribute NR-PARTS on class BOM + Attribute PRICE on class PART The relation is a "general" one: if any attribute of an instance of class PART changes then recalculate all attributes of the corresponding instance of class BOM. Several things have to be noted here: Adding a part to a Bom is done by the following steps (not using Cells but the - say - traditional approach): 0. BOM instance is already there 1. Create an instance of class PART 2. Create an instance of relation IS-USED-IN 3. Set the LHS (left hand side) of the relation to the object id of the new part 4. Set the RHS of the relation to the object id of the BOM instance Now, the update mechanism in this traditional approach always crawls all relation instances using the id of the changed object to find all other objects being related to that instance id and sends an update event to all these instances. This should be avoided by limiting the nr of events being fired. Not every related object has to be updated when a part is added. The same is true when the Price attribute of a part is changed: the BOM need not recalculate the nr of parts in it. The intended use case is: Define a relation class that says: update attribute PRICE on instances of class BOM if the attribute PRICE of instances of class PART changes - respecting the fact that a particular instance of class PART is always related to particular instances of class BOM (so update only those affected). A part can be related to more than one BOM. A BOM can have more than one part (well, a simple n:m relation). So, I want to define a class-level dependency between classes BOM and PART by defining the slots PRICE in BOM and NR-PARTS, PRICE in PART as cells. Using whatever mechanism out of the Cells package I defined the relation between these Cell slots. As there will be millions of instances of PART and (a few less) instances of BOMs I want to have to define the dependency just once while still being able to overwrite the firing rules and the dependency rules between any two instances of classes BOM and PART. The reminder of the email exchange is now discussion the various aspects of this and also what Cells really are ;-) >> The use case for this will be: I create a dependency between >> class BOM (bill of material) and Part (individual components). >> Once having create that class synapse-connection every instance >> created of the classes BOM and Part "knows" of the dependency ... > > A couple of things here. > > (1) I myself have lately stepped up my understanding of Cells, viz, > that a lot of the power comes from being instance-oriented, as in > different instances of the same class can have different rules for > the same slot. Note that def-c-output compromises this by being > class-oriented, so now I have a solid reason for my long-held vague > discomfort with def-c-outputs which are not really outputs but > instead feed back into the model by setf-ing c-input cells. So this > talk of relations between classes has me thinking "you better have > a good reason". <g> > > (2) I forget the second thing. > >> and after being related to specific instance (say, a Part "High >> Pressure Turbine, Serial Nr 0001" is related to an instance "As >> Built BOM , Baseline 001" of class BOM) then, when the Part "High >> Pressure Turbine, Serial Nr 0001" gets changed.. > > You lost me. Do you mean it gets changed in the sense that some > other part is now being used, or in the sense that some attribute > of the part (say, the price of the turbine) changes? Both: If a new part is added or a part is deleted from the BOM or the price attribute is changed. >> the synapse between the two classes triggers the /right/ instance >> of class BOM, here the instance "As Built BOM , Baseline 001". > > "Triggers"? Do you mean, the total on the BOM would have to be > changed to reflect the changed turbine price? Yes. > Anyway, it does not sound as if the two classes require dataflow, > it sounds as if each instance of each class will require that > dataflow with some other instance. Agreed. > As much as I talk about instance-oriented programming, hey, if you > author a cell in a rule supplied in an initform or default-initarg, > guess what? You get class-oriented behavior. :) Just do not > override those rules at make-instance time. :) Aha! #### It all started with my email: Kenny, while designing my app here I am stuck with the following problem: Using Cells I want to build an object management kernel (to be used within my Product Information Management Application). This kernel has to implement a basic set of operations to manage objects (instances of any kind of class) such as Create, Read, Update (using Check-in / Check-Out into / from Vaults) and such. While Cells is perfect for modeling dependencies between instances of objects (using synapses) I am now about to implement relations and dependencies between classes. The use case for this will be: I create a dependency between class BOM (bill of material) and Part (individual components). Once having create that class synapse-connection every instance created of the classes BOM and Part "knows" of the dependency and after being related to specific instance (say, a Part "High Pressure Turbine, Serial Nr 0001" is related to an instance "As Built BOM , Baseline 001" of class BOM) then, when the Part "High Pressure Turbine, Serial Nr 0001" gets changed the synapse between the two classes triggers the /right/ instance of class BOM, here the instance "As Built BOM , Baseline 001". Hmmm - you, as the expert here, would you: 1) Create a new class of synapses 2) Create a new class of cells 3) Implement a new dependency mechanism 4) Do something else (and for every case I dare to ask: Why ?) ;-) - --- EOM (End Of Mail) --- -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (Darwin) iEYEARECAAYFAkKSa34ACgkQfYXhf9DGKdZlQQCfSOuHaMxVtJbtOGv/Jk7efALw XXkAnimcQTvB4hq32b3XvXCOcyscVV94 =eoZc -----END PGP SIGNATURE-----

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[cells-devel] Synapse note
by Kenny Tilton 23 May '05

23 May '05

I forgot to mention something about the new Synapse technology: you can now have a synapse on an arbitrary sub-form within a rule. Silly example: :circumference (c? (* 2 (f-sensitivity :l+w (:delta 10) (+ (^length) (^width)))) Not sure if it matters, but I get a big kick out of that for some reason. kt -- Cells? Cello?: http://www.common-lisp.net/project/cells/ Cells-Gtk?: http://www.common-lisp.net/project/cells-gtk/ Why Lisp? http://lisp.tech.coop/RtL%20Highlight%20Film "Doctor, I wrestled with reality for forty years, and I am happy to state that I finally won out over it." -- Elwood P. Dowd

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[cells-devel] Ooops: with-c-cache
by Kenny Tilton 20 May '05

20 May '05

Ooops. I yanked this new macro out of the use case just before posting everything to CVS, forgetting some of you old Cells hands would likely not update from CVS before trying the use case. Here is with-c-cache, not found in cells/constructirs.lisp (defmacro with-c-cache ((fn) &body body) (let ((new (gensym))) `(or (bwhen (,new (progn ,@body)) (funcall ,fn ,new .cache)) .cache))) kt -- Cells? Cello?: http://www.common-lisp.net/project/cells/ Cells-Gtk?: http://www.common-lisp.net/project/cells-gtk/ Why Lisp? http://lisp.tech.coop/RtL%20Highlight%20Film "Doctor, I wrestled with reality for forty years, and I am happy to state that I finally won out over it." -- Elwood P. Dowd

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cells-devel May 2005