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Re: local/set
by Stefan Langerman 11 Dec '99

11 Dec '99

Evan Simpson <evan(a)4-am.com> wrote: > "Phillip J. Eby" wrote: > > > Let: allows read-only variables to be computed whose values are usable > > within a DTML nesting scope. > > > > Local: allows writable variables to be computed, whose values are usable > > and changeable within a DTML nesting scope. > > > > Set: singleton tag that changes the value of a "local" variable, as long as > > it was defined in the innermost surrounding "local" block. > > Given these use-cases, consider the following variant of Let: > > <dtml-let x="1+1" person: firstname=" 'fred' " weight="180"> > <dtml-var x>, <dtml-var firstname>, <dtml-var "person.weight"> > <dtml-call "person.set('weight', 185)"> > <dtml-var weight> > </dtml-let> > > That is, every variable set after a colon-terminated singleton 'foo:' is also > a mutable (through .set()) attribute of 'foo'. > > Cheers, > > Evan @ 4-am I agree that Let and Local would be redundant. Just set would be enough: <dtml-let x="hello"> <dtml-var x> <dtml-set x="world"> <dtml-var x> </dtml-let x> Also note the argument in the </dtml-let x> which might make things more readable if there are nested lets. If you just want to declare a variable (without a value), you could also say <dtml-let x>. And maybe we could even live without set if we extend the use of Let: <dtml-let x="hello"> <dtml-var x> <dtml-let x="world"> <dtml-var x> </dtml-let x> Personally, I prefer the first solution, but if we really want to avoid introducing new tags, just say that <dtml-let> sets the value of a local var, </dtml-let> unsets it... Another thing I would love to see is a clean way to pass parameters to dtml methods, instead of putting them in REQUEST. like: <dtml-var some_method args="arg1:val1,arg2:val2"> instead of: <dtml-call "REQUEST.set('arg1',val1)"> <dtml-call "REQUEST.set('arg2',val2)"> <dtml-var some_method>

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Re: [Zope] Multi tier partitioning meaningful in some Zope apps ?
by Jerry.Spicklemire＠IFLYATA.COM 10 Dec '99

10 Dec '99

Greetings Zope Gurus, I am immensely intrigued by the possibility of leveraging the innate Object / Relational features in PostgreSQL as an alternate storage method for Zope Objects, especially Code Objects. In PostgreSQL, new data types may be defined, with inheritence relationships such that base properties may be derived from parent data types. The classic University Postgres example is to start with goemetric primitives (node, cell, etc.), and build up to multi-dimensional object data types. One might then expand to a map data type, and from here define the boundaries of nations, super-imposed on the globe. Think about defining an element data type, then an amino acid molecule, which could be used to describe a gene, and then a chromosome. A machine part data type, and then a space shuttle. You get the idea. Why not Zope Object data types, for DTML Methods, DTML Documents, External Methods, etc. If there's a pressing need to further partition content and code, this might be one very clear way to achieve that end. Just pondering the range of new data types for Zope makes me dizzy! Imagine reverse-sorting a PostgreSQL Table on the Origination Date / Time Property of DTML Methods to step back to the version right before you broke an application . . . Later, Jerry S.

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(whoops, hit send too early) Re: local/set (was RE: Zope direction and 2.2roadmap...) direction and 2.2roadmap...)
by Phillip J. Eby 10 Dec '99

10 Dec '99

At 12:01 AM 12/10/99 -0500, Christopher Petrilli wrote: > >Can you clearly explain in 1 sentence each, what each tag is for? (This >includes let) > Let: allows read-only variables to be computed whose values are usable within a DTML nesting scope. Local: allows writable variables to be computed, whose values are usable and changeable within a DTML nesting scope. Set: singleton tag that changes the value of a "local" variable, as long as it was defined in the innermost surrounding "local" block.

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FSSesion v0.2.0
by Pavlos Christoforou 10 Dec '99

10 Dec '99

Zopistas - FSSession 0.2.0 is available at: http://www.zope.org/Members/gaaros/FSSession FSSession is now a product that participates in Zope's transaction machinery. It should be more efficient and includes a method to return appropriately formed URLs depending on client support of cookies. Pavlos

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local/set (was RE: Zope direction and 2.2 roadmap...)
by Phillip J. Eby 10 Dec '99

10 Dec '99

At 04:15 PM 12/9/99 -0500, Brian Lloyd wrote: > >I will definitely be interested in feedback from Zopistas on >the effect of PMs on the sort of problems that tags like "local" >and "set" propose to solve. Well, for the situations I wrote local/set for, PythonMethods will have zero impact. Here's an example of the type of situation I use local/set for:     HTML Code that uses bgcolor variable in a variety of ways  For a PythonMethod to help with something like this, it would have to embed knowledge of HTML-ish things (like color codes). IMHO, DTML methods are supposed to deal with HTML, PythonMethods should deal with business rules. Can you do the above without local and set? Well, you could use REQUEST.set, which, IMHO, is an ugly hack, because it forces the use of a global variable. What if a Product does this and overwrites a REQUEST field that you wanted? It's just plain bad design to use global variables when what you want is a local one. You could do this by breaking up your DTML page into smaller methods, instead, and do something like:      But this is only (barely) reasonable if one such variable is involved, and doubles the number of methods needed to do something [that should be] quite simple. Now try it with a background color and a couple of different icons, controlled by different properties/methods of the object being rendered. It's not only unreasonable, it's impossible without duplicating logic in ridiculous nestings. Similar issues can come up when you need to conditionally include tables in the FROM clause of an SQL query being generated in DTML. IMHO, PythonMethods won't fix any of these issues. But local/set are useful for any DTML situation where one or more variables need to be set conditionally and then reused throughout the rendering. And, they make DTML easier to explain to those new to Zope. I can't tell you how many times I've had somebody starting with Zope ask me, "So how do I make a variable?" because they were trying to do something like my examples above. (And who then made a nasty face at me when they were presented with the REQUEST.set and "split your page" 'solutions'.) So my take on it is that local/set are needed to improve DTML reusability independent of the presence of PythonMethods. But you probably already knew that. :) >The subject of DTML is a volatile one at the moment, as I'm >sure you've seen from the list :) One of the big goals for >2.2 is to see how effective the integration of Python Methods >is at reducing the necessity for complexity in DTML. The >hope is that PMs will help reduce the need to introduce ever >more constructs into DTML, so I plan to wait a while so that >we can evaluate the results of the PM effort before adding >anything more to the DTML core. It would be nice to have a clear "yes" or "no" answer sometime soon, though, so that if "local"/"set" aren't going to go in the official distro I can pull them out as a seperate module from "let", for easier distribution of my projects at work. Also, wrt "ever more constructs", I don't believe there are any new constructs to add, since with the addition of local/set, DTML would have effectively the same set of constructs that Python does for bodies of code. What else would one add?

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OFSP/help?
by Robin Becker 10 Dec '99

10 Dec '99

I see a checkin about the OFSP/help directory which is supposed to provide lots of files. I cvs'd but don't get these? -- Robin Becker

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latest checkins cause problems
by Robin Becker 10 Dec '99

10 Dec '99

Last night I updated my setup and now can't seem to get things to work. I get my root page after a long wait;can't get the manage page at all. tried control-c in the command window, but it seems to be hanging. Any ideas? -- Robin Becker

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ZInstaller product pre-announcement
by Stefan Langerman 10 Dec '99

10 Dec '99

Hello everyone, I just uploaded my new product: ZInstaller on the zope website: http://www.zope.org/Members/slef/ZInstaller It is an attempt to automate the installation of products in your zope. Ultimately, you should be able to install a product in a couple of clicks. No more shell commands! You might be interested to look at it if you want to install other people's products more easily. You might also want to take a look if you have developed some product and want people to be able to install them in two clicks. The product is in very early development, and I would really appreciate any comments you might have about it. I might also need your help to improve it. Details on all that on the product release page. Stefan.

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ZClass shows properties of parent
by Loren Stafford 10 Dec '99

10 Dec '99

When I try to access the properties of my ZClass, I get the properties of the containing object instead. Can anyone see why? I have a "members" folder that contains instances of my ZClass "MemberRecordClass". That class is not based on any other class except the default class (is that SimpleClass?). Its objects just contain properties, such as "member_name", "member_email", etc. The IDs of instances are the same as the login IDs of authenticated users. >From another unrelated folder, I access the member records with DTML like this: <dtml-with members> Object: "<dtml-var "_[AUTHENTICATED_USER.getUserName()]" html_quote>"; <dtml-with "_[AUTHENTICATED_USER.getUserName()]"> id: "<dtml-var id>"; propertyItems: "<dtml-var propertyItems>" </dtml-with> </dtml-with> But I get output like this: Object: "<MemberRecordClass instance at 016A8CA0>"; id: "lstaffor"; propertyItems: "[('title', 'Member Records')]" The title "Member Records" os a property of the "members" folder, not of the member record object. The object description and the object id, however, correspond to a member record instance. This happens both with Zope 2.0.1 ane 2.1.0. -- Thanks -- Loren ===== Loren Stafford mailto:lstaffor@dynalogic.com Mountain View, CA http://www.dynalogic.com/ __________________________________________________ Do You Yahoo!? Thousands of Stores. Millions of Products. All in one place. Yahoo! Shopping: http://shopping.yahoo.com

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Fwd: Re: Reiserfs as the object database
by Patrick Phalen 09 Dec '99

09 Dec '99

I emailed Hans Reiser to ask him to comment on the feasibility of relying on the filesystem to act as the object database (using reiserfs). He had this to say: ---------- ## Forwarded Message ## ---------- Date: Fri, 10 Dec 1999 01:04:43 +0300 From: Hans Reiser <reiser(a)idiom.com> Patrick, I think what you say has a lot of merit, and the areas in which we are extending our functionality will make this easier and easier over time. Features in our next version like item handlers, inheritance, lightweight files/objects, stem compression of filenames, etc., are all aimed at making this more feasible for folks like you to use us as a bottom layer. We would be more than happy to do work on the FS to accomodate your needs for this. That said, don't underestimate the scope of the task, it is a big one, and it is hard for me to promise specific features you will need on a short term basis, I can only say that what you want is in the scope of our long-term vision. I can also say that we welcome all good patches. Sound good? Best, Hans -- Get Linux (http://www.kernel.org) plus ReiserFS (http://devlinux.org/namesys) If you sell an OS or internet appliance, buy a port of ReiserFS! If you need customizations and industrial grade support, we sell them.

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