[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
I agree that it's an issue. In my own defense, what I meant was not that I
didn't think people would use more than one DB. I actually have several apps
(not yet converted to Lift) that use 4 or more persistence units that
represent various legacy databases. Rather, I failed to realize the problem
that would arise from defining the EM factory as a singleton because when I
wrote that code I didn't fully understand how member objects on classes
worked. Other than that, I agree with your post :)
Derek
On Tue, Jun 16, 2009 at 5:38 PM, Meredith Gregory
lgreg.mered...@gmail.comwrote:
Derek,
soapbox
You have just demonstrated a process that i have been talking about for the
last 15 years. People have a blind spot when it comes to thinking
compositionally. They think -- almost to a person -- about god's eye view
solutions where there's only one of some key solution component. They don't
think about solutions that are composed of ... (wait for it)... solutions!
It takes some serious training to think compositionally. Compositional
solutions, however, are the only realistic way to scale. When solutions are
compositional, you can *de*compose. The db example is a case in point. One
of the most natural ways to scale data access is sharding and partitioning
-- which requires upfront machinery to support decomposition of the store.
Lest you feel bad, note that some of the best scientific minds of all time
have fallen prey to this blind spot. Newtonian physics as well as Einstein's
update to Newton's proposal is a non-compositional solution. Quantum
mechanics also exhibits compositional failures. This is why physics is
failing to find proposals that link theories of gravitation (essentially
large scale) to quantum mechanical theories of the other forces (essentially
very small scale) -- the physical theories are non-compositional -- they
don't scale!
One of the real things functional programming has going for it is that the
basic model of computation underlying the means of structuring and
manipulating programs is compositional. That's why it is important to have a
technology like Scala resting atop the incumbent execution model (JVM) being
deployed on web-scale problems. Compositionality is the only way to tackle
applications at global scale.
/soapbox
Thanks for getting the fix to this problem in so quickly.
Best wishes,
--greg
On Tue, Jun 16, 2009 at 11:53 AM, Derek Chen-Becker dchenbec...@gmail.com
wrote:
Using multiple EMs was not something I had considered when I wrote this. I
think that I can modify the code to provide a __nameSalt def to
differentiate instances. Let me work on it and I'll have something soon.
Derek
On 6/16/09, Jean-Luc jlcane...@gmail.com wrote:
For your information, here is an extract of source code of RequestVarEM :
Trait RequestVarEM extends ScalaEntityManager with ScalaEMFactory {
object emVar extends RequestVar[EntityManager](openEM()) { ... }
}
EntityManager is stored in the singleton emVar; so, all db access of
Model objects are made using the singleton emVar.
= trait RequestVarEM allow only one connection to a database within the
same HttpRequest context.
Jean-Luc
2009/6/15 Jean-Luc jlcane...@gmail.com
Hello,
I have two databases, db1 (a.k.a. Motorbike) and db2 (a.k.a. Motorway)
defined with RequestVarEM :
- object ModelDb1 extends LocalEMF(db1) with RequestVarEM //
Motorbike database
- object ModelDb2 extends LocalEMF(db2) with RequestVarEM // Motorway
database
I thought one could access to any databases independently from any
snippet as long as the correct Model object were used (ModelDb1 or ModelDb2
for exemple) ; but when I access both databases from the same page, the
second database access issues a Named query not found exception.
I have two snippets, one to display a list of motorbike, another to
display a list of motorway :
- page1 :
ModelDb1.createNamedQuery[Motorbike](Motorbike.findAll).getResultList() =
ok
- page2
: ModelDb2.createNamedQuery[Motorway](Motorway.findAll).getResultList() =
ok
- page3 : calling from page 3 motorbike motorway snippets : Named
query not found: Motorway.findAll
- page4 : calling from page 4 motorway motorbike snippets : Named
query not found: Motorbike.findAll
- page3 changing the query of *Motorway* snippet :
-
ModelDb2.createNamedQuery[*Motorbike*](*Motorbike*.findAll).getResultList()
= it's ok and I do NOT have an exception !
I joined a sample application, ...
any idea about this issue ?
(bad use of LocalEMF in the application code ? issue with LocalEMF or
RequestVarEM ?)
Jean-Luc
PS :
I don't know if it's related but I have this in the log :
[INFO] Checking for multiple versions of scala
[WARNING] Multiple versions of scala libraries detected!
--
Jean-Luc Canela
jlcane...@gmail.com
--
Jean-Luc Canela
jlcane...@gmail.com
--
L.G. Meredith
Managing Partner
Biosimilarity LLC
1219 NW 83rd St
Seattle, WA
[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
In Derek's defense, it's not how objects in classes work but how Lift
RequestVars work. Scala objects in classes aren't global singletons, just
per-class-instance singletons. But a Lift ReuqestVar object in a class is
pretty much a global singleton (unless you do some hacking like Derek did).
--j
On Tue, Jun 16, 2009 at 11:14 PM, Derek Chen-Becker
dchenbec...@gmail.comwrote:
I agree that it's an issue. In my own defense, what I meant was not that I
didn't think people would use more than one DB. I actually have several apps
(not yet converted to Lift) that use 4 or more persistence units that
represent various legacy databases. Rather, I failed to realize the problem
that would arise from defining the EM factory as a singleton because when I
wrote that code I didn't fully understand how member objects on classes
worked. Other than that, I agree with your post :)
Derek
On Tue, Jun 16, 2009 at 5:38 PM, Meredith Gregory
lgreg.mered...@gmail.com wrote:
Derek,
soapbox
You have just demonstrated a process that i have been talking about for
the last 15 years. People have a blind spot when it comes to thinking
compositionally. They think -- almost to a person -- about god's eye view
solutions where there's only one of some key solution component. They don't
think about solutions that are composed of ... (wait for it)... solutions!
It takes some serious training to think compositionally. Compositional
solutions, however, are the only realistic way to scale. When solutions are
compositional, you can *de*compose. The db example is a case in point.
One of the most natural ways to scale data access is sharding and
partitioning -- which requires upfront machinery to support decomposition of
the store.
Lest you feel bad, note that some of the best scientific minds of all time
have fallen prey to this blind spot. Newtonian physics as well as Einstein's
update to Newton's proposal is a non-compositional solution. Quantum
mechanics also exhibits compositional failures. This is why physics is
failing to find proposals that link theories of gravitation (essentially
large scale) to quantum mechanical theories of the other forces (essentially
very small scale) -- the physical theories are non-compositional -- they
don't scale!
One of the real things functional programming has going for it is that the
basic model of computation underlying the means of structuring and
manipulating programs is compositional. That's why it is important to have a
technology like Scala resting atop the incumbent execution model (JVM) being
deployed on web-scale problems. Compositionality is the only way to tackle
applications at global scale.
/soapbox
Thanks for getting the fix to this problem in so quickly.
Best wishes,
--greg
On Tue, Jun 16, 2009 at 11:53 AM, Derek Chen-Becker
dchenbec...@gmail.com wrote:
Using multiple EMs was not something I had considered when I wrote this.
I think that I can modify the code to provide a __nameSalt def to
differentiate instances. Let me work on it and I'll have something soon.
Derek
On 6/16/09, Jean-Luc jlcane...@gmail.com wrote:
For your information, here is an extract of source code of RequestVarEM
:
Trait RequestVarEM extends ScalaEntityManager with ScalaEMFactory {
object emVar extends RequestVar[EntityManager](openEM()) { ... }
}
EntityManager is stored in the singleton emVar; so, all db access of
Model objects are made using the singleton emVar.
= trait RequestVarEM allow only one connection to a database within the
same HttpRequest context.
Jean-Luc
2009/6/15 Jean-Luc jlcane...@gmail.com
Hello,
I have two databases, db1 (a.k.a. Motorbike) and db2 (a.k.a. Motorway)
defined with RequestVarEM :
- object ModelDb1 extends LocalEMF(db1) with RequestVarEM //
Motorbike database
- object ModelDb2 extends LocalEMF(db2) with RequestVarEM //
Motorway database
I thought one could access to any databases independently from any
snippet as long as the correct Model object were used (ModelDb1 or
ModelDb2
for exemple) ; but when I access both databases from the same page, the
second database access issues a Named query not found exception.
I have two snippets, one to display a list of motorbike, another to
display a list of motorway :
- page1 :
ModelDb1.createNamedQuery[Motorbike](Motorbike.findAll).getResultList()
=
ok
- page2
: ModelDb2.createNamedQuery[Motorway](Motorway.findAll).getResultList()
=
ok
- page3 : calling from page 3 motorbike motorway snippets : Named
query not found: Motorway.findAll
- page4 : calling from page 4 motorway motorbike snippets : Named
query not found: Motorbike.findAll
- page3 changing the query of *Motorway* snippet :
-
ModelDb2.createNamedQuery[*Motorbike*](*Motorbike*.findAll).getResultList()
= it's ok and I do NOT have an exception !
I joined a sample application, ...
any idea about this issue ?
(bad use of LocalEMF in the application code ? issue
[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
You made an assumption and programmed a solution based on the knowledge you
had at the time. Thats fine and there is nothing wrong with it - start with
the simplest solution that fits. If it need to be changed due to changing
requirements, thats fine too. There is a tradeoff in creating a overly
complex solution that fits problems that you think might exist in the future
and simplicity. Also, there is nothing that makes composition an idea that
is only understood and relevant to functional programming as almost seems to
be suggested here.
On Wed, Jun 17, 2009 at 4:14 PM, Derek Chen-Becker dchenbec...@gmail.comwrote:
I agree that it's an issue. In my own defense, what I meant was not that I
didn't think people would use more than one DB. I actually have several apps
(not yet converted to Lift) that use 4 or more persistence units that
represent various legacy databases. Rather, I failed to realize the problem
that would arise from defining the EM factory as a singleton because when I
wrote that code I didn't fully understand how member objects on classes
worked. Other than that, I agree with your post :)
Derek
On Tue, Jun 16, 2009 at 5:38 PM, Meredith Gregory
lgreg.mered...@gmail.com wrote:
Derek,
soapbox
You have just demonstrated a process that i have been talking about for
the last 15 years. People have a blind spot when it comes to thinking
compositionally. They think -- almost to a person -- about god's eye view
solutions where there's only one of some key solution component. They don't
think about solutions that are composed of ... (wait for it)... solutions!
It takes some serious training to think compositionally. Compositional
solutions, however, are the only realistic way to scale. When solutions are
compositional, you can *de*compose. The db example is a case in point.
One of the most natural ways to scale data access is sharding and
partitioning -- which requires upfront machinery to support decomposition of
the store.
Lest you feel bad, note that some of the best scientific minds of all time
have fallen prey to this blind spot. Newtonian physics as well as Einstein's
update to Newton's proposal is a non-compositional solution. Quantum
mechanics also exhibits compositional failures. This is why physics is
failing to find proposals that link theories of gravitation (essentially
large scale) to quantum mechanical theories of the other forces (essentially
very small scale) -- the physical theories are non-compositional -- they
don't scale!
One of the real things functional programming has going for it is that the
basic model of computation underlying the means of structuring and
manipulating programs is compositional. That's why it is important to have a
technology like Scala resting atop the incumbent execution model (JVM) being
deployed on web-scale problems. Compositionality is the only way to tackle
applications at global scale.
/soapbox
Thanks for getting the fix to this problem in so quickly.
Best wishes,
--greg
On Tue, Jun 16, 2009 at 11:53 AM, Derek Chen-Becker
dchenbec...@gmail.com wrote:
Using multiple EMs was not something I had considered when I wrote this.
I think that I can modify the code to provide a __nameSalt def to
differentiate instances. Let me work on it and I'll have something soon.
Derek
On 6/16/09, Jean-Luc jlcane...@gmail.com wrote:
For your information, here is an extract of source code of RequestVarEM
:
Trait RequestVarEM extends ScalaEntityManager with ScalaEMFactory {
object emVar extends RequestVar[EntityManager](openEM()) { ... }
}
EntityManager is stored in the singleton emVar; so, all db access of
Model objects are made using the singleton emVar.
= trait RequestVarEM allow only one connection to a database within the
same HttpRequest context.
Jean-Luc
2009/6/15 Jean-Luc jlcane...@gmail.com
Hello,
I have two databases, db1 (a.k.a. Motorbike) and db2 (a.k.a. Motorway)
defined with RequestVarEM :
- object ModelDb1 extends LocalEMF(db1) with RequestVarEM //
Motorbike database
- object ModelDb2 extends LocalEMF(db2) with RequestVarEM //
Motorway database
I thought one could access to any databases independently from any
snippet as long as the correct Model object were used (ModelDb1 or
ModelDb2
for exemple) ; but when I access both databases from the same page, the
second database access issues a Named query not found exception.
I have two snippets, one to display a list of motorbike, another to
display a list of motorway :
- page1 :
ModelDb1.createNamedQuery[Motorbike](Motorbike.findAll).getResultList()
=
ok
- page2
: ModelDb2.createNamedQuery[Motorway](Motorway.findAll).getResultList()
=
ok
- page3 : calling from page 3 motorbike motorway snippets : Named
query not found: Motorway.findAll
- page4 : calling from page 4 motorway motorbike snippets : Named
query not found: Motorbike.findAll
- page3 changing the query of *Motorway* snippet :
-
[Lift] Scaladoc Generation
This is probably more of a maven question, but I searched through the maven docs and the closest I could find is the site plugin - although this appears to generate a whole load of cruft, so I was wondering if someone could shed some light. I have managed to generate the API docs using mvn scala:doc, but the documentation is split up among the different packages. How would I generate the docs as shown at http://scala-tools.org/scaladocs/liftweb/1.0/ where it shows them all merged together? Kind Regards, Matt --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Scala learning tool
All the Scala books and tutorials recommend using the Scala interactive shell to set up scenarios and learn how Scala works. I agree, but my problem was the (apparent) lack of something like Python's dir(object) call, which gives you all the 'names' available; Ruby and Erlang have similar commands, but not, as far as I know, Scala. I did find a little script that does just that at: http://lousycoder.com/blog/index.php?/archives/91-Scala-Querying-an-objects-fields-and-methods-with-reflection.html with the source at: http://gist.github.com/87519 I compiled it, and when I import it, it works just dandy: scala import ScalaReflection._ import ScalaReflection._ scala 3.methods__ hashCode reverseBytes(int) compareTo(Object) compareTo(Integer) equals(Object) toString(int,int) toString(int) ... scala 3.fields__ MIN_VALUE MAX_VALUE TYPE digits DigitTens DigitOnes sizeTable value SIZE serialVersionUID Perhaps there is something like this already built-in to Scala, but I can't find it... if not, it may be worthwhile adding. Now, what I want to know is: is there a way to load an actual Lift session into the interactive command interpreter, so I can create and check out out functions, etc? I remember doing that with Ruby and Rails back in the day. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
In my own defense ... failed to realize the problem that would arise from defining the EM factory as a singleton Are you being honest here Derek? Was not the real problem that you failed to truly embrace the shape of the paradoxical combinator? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
Read this and join me in having your brains implode: http://www.mail-archive.com/everything-l...@googlegroups.com/msg05959.html On Wed, Jun 17, 2009 at 11:07 AM, TSP tim.pig...@optrak.co.uk wrote: In my own defense ... failed to realize the problem that would arise from defining the EM factory as a singleton Are you being honest here Derek? Was not the real problem that you failed to truly embrace the shape of the paradoxical combinator? -- Viktor Klang Scala Loudmouth --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
Hi Derek,
I had issues with the http proxy, so I checked building from source code
(scalajpa + lift-jpa) .
It's perfect, just what I need !
Thank you very much ;-)
Jean-Luc
2009/6/16 Derek Chen-Becker dchenbec...@gmail.com
OK, I just checked in code that should allow this to work. Could you please
test and make sure that it's functioning correctly?
Thanks,
Derek
On 6/16/09, Derek Chen-Becker dchenbec...@gmail.com wrote:
Using multiple EMs was not something I had considered when I wrote this. I
think that I can modify the code to provide a __nameSalt def to
differentiate instances. Let me work on it and I'll have something soon.
Derek
On 6/16/09, Jean-Luc jlcane...@gmail.com wrote:
For your information, here is an extract of source code of RequestVarEM :
Trait RequestVarEM extends ScalaEntityManager with ScalaEMFactory {
object emVar extends RequestVar[EntityManager](openEM()) { ... }
}
EntityManager is stored in the singleton emVar; so, all db access of
Model objects are made using the singleton emVar.
= trait RequestVarEM allow only one connection to a database within the
same HttpRequest context.
Jean-Luc
2009/6/15 Jean-Luc jlcane...@gmail.com
Hello,
I have two databases, db1 (a.k.a. Motorbike) and db2 (a.k.a. Motorway)
defined with RequestVarEM :
- object ModelDb1 extends LocalEMF(db1) with RequestVarEM //
Motorbike database
- object ModelDb2 extends LocalEMF(db2) with RequestVarEM // Motorway
database
I thought one could access to any databases independently from any
snippet as long as the correct Model object were used (ModelDb1 or ModelDb2
for exemple) ; but when I access both databases from the same page, the
second database access issues a Named query not found exception.
I have two snippets, one to display a list of motorbike, another to
display a list of motorway :
- page1 :
ModelDb1.createNamedQuery[Motorbike](Motorbike.findAll).getResultList() =
ok
- page2
: ModelDb2.createNamedQuery[Motorway](Motorway.findAll).getResultList() =
ok
- page3 : calling from page 3 motorbike motorway snippets : Named
query not found: Motorway.findAll
- page4 : calling from page 4 motorway motorbike snippets : Named
query not found: Motorbike.findAll
- page3 changing the query of *Motorway* snippet :
-
ModelDb2.createNamedQuery[*Motorbike*](*Motorbike*.findAll).getResultList()
= it's ok and I do NOT have an exception !
I joined a sample application, ...
any idea about this issue ?
(bad use of LocalEMF in the application code ? issue with LocalEMF or
RequestVarEM ?)
Jean-Luc
PS :
I don't know if it's related but I have this in the log :
[INFO] Checking for multiple versions of scala
[WARNING] Multiple versions of scala libraries detected!
--
Jean-Luc Canela
jlcane...@gmail.com
--
Jean-Luc Canela
jlcane...@gmail.com
--
Jean-Luc Canela
jlcane...@gmail.com
--~--~-~--~~~---~--~~
You received this message because you are subscribed to the Google Groups
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[Lift] Re: Hiring Lift Developers
Hi Dived, the just opened http://scala-forum.org has a sub forum for scala job openings: http://scala-forum.org/list.php?6 Feel free to post your vacancy there. Regards, Christian On Jun 15, 7:32 pm, David LaPalomento dlapalome...@novell.com wrote: Hi all, My team has recently started a project based around Lift and we're looking at bringing on some passionate, full-time developers to make that happen. It's a pretty ambitious effort and we expect to be pushing the technology envelope in real-time communication (CometActors have already been a huge help here) and user experience for web applications. If you think you might be interested, drop me an email and I'd be glad to go into greater detail about the project. Also, apologies in advance if I shouldn't be posting this sort of thing to the list. Regards, David --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Firebug error message for AJAX
On Jun 17, 12:53 am, Charles F. Munat c...@munat.com wrote:
I have the import statment and the LiftRules.jsArtifacts = YUIArtifacts
in Boot, but the script tag for the liftYUI.js script is not being
inserted. I guess I could add it manually, but isn't Lift supposed to
insert it?
Nope it doesn't insert it automatically ...
Thanks!
Chas.
marius d. wrote:
Also please see:http://wiki.liftweb.net/index.php/HowTo_use_Lift_with_YUI
Marius
On Jun 16, 11:58 pm, marius d. marius.dan...@gmail.com wrote:
You need one more
script src=/classpath/liftYUI.js type=text/javascript/script
Br's,
Marius
On Jun 16, 11:30 pm, Charles F. Munat c...@munat.com wrote:
I'm getting the following error in Firebug:
YAHOO.lift is undefined
url = YAHOO.lift.buildURI(addPageName('/...nSuccess(res);}, failure :
onFailure });
I have the following scripts:
script src=/scripts/yahoo-dom-event/yahoo-dom-event.js
type=text/javascript/script
script src=/scripts/utilities/utilities.js
type=text/javascript/script
script src=/scripts/json/json-min.js type=text/javascript/script
script src=/scripts/connection/connection-min.js
type=text/javascript/script
script type=text/javascript src=/ajax_request/liftAjax.js/script
Any ideas?
Chas.
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[Lift] Re: David and Lift @ QCon
Really enjoined ! ... Thank David and congrats ! Br's, Marius On Jun 17, 5:41 pm, Viktor Klang viktor.kl...@gmail.com wrote: For those of us who weren't there:http://www.infoq.com/interviews/Lift-Scala-David-Pollack Awesome interview Dave! Cheers, -- Viktor Klang Scala Loudmouth --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
Oliver Lambert wrote: Do we need to do some sort of course to understand this language? This could help: http://www.mitadmissions.org/topics/apply/the_freshman_application/index.shtml :) -- Eric Bowman Boboco Ltd ebow...@boboco.ie http://www.boboco.ie/ebowman/pubkey.pgp +35318394189/+353872801532 --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
Isn't this just the result of JIT development? Don't need something
right now, don't implement it. If you need it later, refactor.
I'm probably looking at this too much from a low level grunt developer.
I understand that when developing a framework or anything with a public
API these are important issues, but that's what bugtrackers are for!
I'm all for composability, but it shouldn't be a religion :-) (--
please note the smiley!)
--Andrew
Derek Chen-Becker wrote:
I agree that it's an issue. In my own defense, what I meant was not
that I didn't think people would use more than one DB. I actually have
several apps (not yet converted to Lift) that use 4 or more
persistence units that represent various legacy databases. Rather, I
failed to realize the problem that would arise from defining the EM
factory as a singleton because when I wrote that code I didn't fully
understand how member objects on classes worked. Other than that, I
agree with your post :)
Derek
On Tue, Jun 16, 2009 at 5:38 PM, Meredith Gregory
lgreg.mered...@gmail.com mailto:lgreg.mered...@gmail.com wrote:
Derek,
soapbox
You have just demonstrated a process that i have been talking
about for the last 15 years. People have a blind spot when it
comes to thinking compositionally. They think -- almost to a
person -- about god's eye view solutions where there's only one
of some key solution component. They don't think about solutions
that are composed of ... (wait for it)... solutions! It takes some
serious training to think compositionally. Compositional
solutions, however, are the only realistic way to scale. When
solutions are compositional, you can _/de/_compose. The db example
is a case in point. One of the most natural ways to scale data
access is sharding and partitioning -- which requires upfront
machinery to support decomposition of the store.
Lest you feel bad, note that some of the best scientific minds of
all time have fallen prey to this blind spot. Newtonian physics as
well as Einstein's update to Newton's proposal is a
non-compositional solution. Quantum mechanics also exhibits
compositional failures. This is why physics is failing to find
proposals that link theories of gravitation (essentially large
scale) to quantum mechanical theories of the other forces
(essentially very small scale) -- the physical theories are
non-compositional -- they don't scale!
One of the real things functional programming has going for it is
that the basic model of computation underlying the means of
structuring and manipulating programs is compositional. That's why
it is important to have a technology like Scala resting atop the
incumbent execution model (JVM) being deployed on web-scale
problems. Compositionality is the only way to tackle applications
at global scale.
/soapbox
Thanks for getting the fix to this problem in so quickly.
Best wishes,
--greg
On Tue, Jun 16, 2009 at 11:53 AM, Derek Chen-Becker
dchenbec...@gmail.com mailto:dchenbec...@gmail.com wrote:
Using multiple EMs was not something I had considered when I
wrote this. I think that I can modify the code to provide a
__nameSalt def to differentiate instances. Let me work on it
and I'll have something soon.
Derek
On 6/16/09, *Jean-Luc* jlcane...@gmail.com
mailto:jlcane...@gmail.com wrote:
For your information, here is an extract of source code of
RequestVarEM :
Trait RequestVarEM extends ScalaEntityManager with
ScalaEMFactory {
object emVar extends
RequestVar[EntityManager](openEM()) { ... }
}
EntityManager is stored in the singleton emVar; so, all db
access of Model objects are made using the singleton emVar.
= trait RequestVarEM allow only one connection to a
database within the same HttpRequest context.
Jean-Luc
2009/6/15 Jean-Luc jlcane...@gmail.com
mailto:jlcane...@gmail.com
Hello,
I have two databases, db1 (a.k.a. Motorbike) and db2
(a.k.a. Motorway) defined with RequestVarEM :
- object ModelDb1 extends LocalEMF(db1) with
RequestVarEM // Motorbike database
- object ModelDb2 extends LocalEMF(db2) with
RequestVarEM // Motorway database
I thought one could access to any databases
independently from any snippet as long as the correct
Model object were used (ModelDb1 or ModelDb2 for
exemple) ; but when I access both databases from the
same page, the second database access issues a Named
[Lift] simple syntax question
I would like to include a variable value in an input tag in my .html
file. I have defined a tag as follows:
def upload(xhtml: Group): NodeSeq =
if (S.get_?) {
bind(ul, chooseTemplate(choose, get, xhtml),
file_upload - fileUpload(ul = theUpload(Full
(ul))),
batch - currBatch
)
}
thus,
choose:get
ul:batch/
/choose:get
returns the variable value that I need
How can I retrieve this variable for the value= attribute of my
input tag? For instance, right now I am trying to do it like this:
input name=batch type=hidden value=ul:batch/ /
but that is not working. It also doesn't work like this:
input name=batch type=hidden value=ul:batch/ /
Thanks,
David
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[Lift] Re: David and Lift @ QCon
I do wish they'd make their videos downloadable... On Wed, Jun 17, 2009 at 5:22 PM, marius d. marius.dan...@gmail.com wrote: Really enjoined ! ... Thank David and congrats ! Br's, Marius On Jun 17, 5:41 pm, Viktor Klang viktor.kl...@gmail.com wrote: For those of us who weren't there: http://www.infoq.com/interviews/Lift-Scala-David-Pollack Awesome interview Dave! Cheers, -- Viktor Klang Scala Loudmouth --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: David and Lift @ QCon
On Wed, Jun 17, 2009 at 7:41 AM, Viktor Klang viktor.kl...@gmail.comwrote: For those of us who weren't there: http://www.infoq.com/interviews/Lift-Scala-David-Pollack Awesome interview Dave! Thanks. Cheers, -- Viktor Klang Scala Loudmouth -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
JIT development ;) In all serious though, its better to have a minimal set of features that work well and can be refactored effortlessly, than to define an entire API and have everything need to change in an updated release. And at the speed this particular fix went in, its hardly hindering progress! On Wed, 2009-06-17 at 08:45 -0700, Andrew Scherpbier wrote: Isn't this just the result of JIT development? Don't need something right now, don't implement it. If you need it later, refactor. I'm probably looking at this too much from a low level grunt developer. I understand that when developing a framework or anything with a public API these are important issues, but that's what bugtrackers are for! I'm all for composability, but it shouldn't be a religion :-) (-- please note the smiley!) --Andrew --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Trivially Set Mapper Scope
Is there a simple way that I can set the record scope on a mapper. For example, if I want to specify a WHERE clause for every query to the database, how would I do this? In my particular case, I want to set the scope based upon the hostname used to service the request, but other usages may involve soft record deletion, etc. Kind Regards, Matt --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: simple syntax question
For now I have fixed the problem by calling a new method in my snippet
that accesses the variable with { } in the input tag. I would be
interested to know if there is a way to do this with a bind tag
directly in the input tag in the .html file, because I feel like my
current solution is a bit of a kludge...
-David
On Jun 17, 12:00 pm, DavidV david.v.villa...@gmail.com wrote:
I would like to include a variable value in an input tag in my .html
file. I have defined a tag as follows:
def upload(xhtml: Group): NodeSeq =
if (S.get_?) {
bind(ul, chooseTemplate(choose, get, xhtml),
file_upload - fileUpload(ul = theUpload(Full
(ul))),
batch - currBatch
)
}
thus,
choose:get
ul:batch/
/choose:get
returns the variable value that I need
How can I retrieve this variable for the value= attribute of my
input tag? For instance, right now I am trying to do it like this:
input name=batch type=hidden value=ul:batch/ /
but that is not working. It also doesn't work like this:
input name=batch type=hidden value=ul:batch/ /
Thanks,
David
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[Lift] Thoughts on separation of display from logic
I wholeheartedly agree with the philosophy of separating the display from the program logic, and am currently getting to grips with the generators, but am finding that now I end up with a degree of markup within my code. Can you think of any caveats to infering the node type passed, and dynamically using the relevant generators to construct the returned node. I am thinking something along the lines of: person:biography textarea style=myStyle cols=20 rows=5 This is a sample of some biography text /textarea /person:biography Where it would automatically infer that it is a textarea, pass through the relevant attributes, and insert whatever function, values, etc I have specified in my snippet. What are your thoughts on this? Brgds, Matt --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Trivially Set Mapper Scope
Matt, There's no way to do this right now. I have an idea... lemme see if I can knock something together for you. Thanks, David On Wed, Jun 17, 2009 at 10:05 AM, Matt Williams m...@makeable.co.uk wrote: Is there a simple way that I can set the record scope on a mapper. For example, if I want to specify a WHERE clause for every query to the database, how would I do this? In my particular case, I want to set the scope based upon the hostname used to service the request, but other usages may involve soft record deletion, etc. Kind Regards, Matt -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
Oliver, The short answer is no. The longer answer is - i worked this all out on my own; so, you guys -- who can program lift on top of scala on top of JVM and are therefore about 20X smarter than i am -- can too. - And also, help is always available, if there is something specific you don't understand, let me know and i will do my best to convey it to you. Best wishes, --greg P.S. Here is a version of the paragraph with links to useful bits of lore from the literature. For myself, i was unhappy with the notion of name. The π-calculihttp://en.wikipedia.org/wiki/Pi-calculusand lambda calculi http://en.wikipedia.org/wiki/Lambda_calculus suffer a dependence on a notion of name. Both families of calculi require at least countably infinitely http://en.wikipedia.org/wiki/Countable many nameshttp://www.cs.nps.navy.mil/research/languages/statements/gordon.html, and a notion of equality on names. If names have no internal structure then these theories *cannot be effectivehttp://en.wikipedia.org/wiki/Computable_function *. The reasons is that the notion of equality must then be realized as an infinitary table which cannot fit in any computer we have access to. Therefore, in effective theories, names must have internal structure. Since they have internal structure and are at least countably infinite, one is in danger of undermining the foundational character of these proposals for computing. Therefore, the only possible solution is that the notion of structured name must come from the notion of program proposed by the model. This argument is airtight. If you want a foundational model of computing with nominal structure, the nominal structure must derive from the notion of computation being put forward, i.e. it must *reflect* the notion of computationhttp://svn.biosimilarity.com/src/open/papers/trunk/concurrency/rho/ex_nihilo_entcs/ex_nihilo_finco.pdf. This gives rise to all kinds of new an beautiful phenomena. One measure of your way into compositional thinking is whether this is happening. Is your approach to compositional thinking beginning to yield whole new aspects of computing, and new 'wholes' of computation, new forms of organization. 2009/6/16 Oliver Lambert olambo...@gmail.com 2009/6/17 Meredith Gregory lgreg.mered...@gmail.com Jeremy, Most excellent question award to you, sir! How to bootstrap thinking compositionally... this is what i did - learn some compositional idioms by heart - do you know the shape of the paradoxical combinator by heart - do you know the data making up a monad - do you know the data making up a distributive law between monads - use them in real world applications and see where they fail - when is calculating the least/greatest fixpoint of a recursive spec for a problem the suboptimal solution - when is a monad not the answer - when is an indexed form of composition inadequate - improve them - is it a situational improvement or - a fundamental improvement - see where the very programming model itself fails - is functional composition the only sort of composition - how is parallel composition like functional composition - is parallel composition easily represented in categorical composition - improve it - what is the view of the world in your notion of composition - play with new programming models - does your new notion of composition give rise to a whole generation of different models - invent new idioms in these models - what are the things these models naturally express - and teach them to someone who wishes to bootstrap thinking compositionally For myself, i was unhappy with the notion of name. The π-calculi and lambda calculi suffer a dependence on a notion of name. Both families of calculi require at least countably infinitely many names, and a notion of equality on names. If names have no internal structure then these theories *cannot be effective*. Do we need to do some sort of course to understand this language? The reasons is that the notion of equality must then be realized as an infinitary table which cannot fit in any computer we have access to. Therefore, in effective theories, names must have internal structure. Since they have internal structure and are at least countably infinite, one is in danger of undermining the foundational character of these proposals for computing. Therefore, the only possible solution is that the notion of structured name must come from the notion of program proposed by the model. This argument is airtight. If you want a foundational model of computing with nominal structure, the nominal structure must derive from the notion of computation being put forward, i.e. it must *reflect* the notion of computation. This gives rise to all kinds of new an beautiful phenomena. One measure of your way into compositional
[Lift] Re: directory structure
The default behavior is to look at for a snippets sub-package to any packages you've configured for snippets, so yes, that's required if you're using snippets. If you're not using a particular feature (i.e. snippets, views, or comet) then the directory can be missing, I think. I can't remember if there's anything special about the model subdirectory or if that's just convention. Derek On Tue, Jun 16, 2009 at 7:35 PM, Oliver Lambert olambo...@gmail.com wrote: In Boot.scala can I call LiftRules.addToPackages multiple times to add multiple directories with snippets in them? Do I have to have a directory structure ending with snippet, for snippets? Do I need the directories comet, model and view, when they are just empty? cheers Oliver --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
On Wed, Jun 17, 2009 at 12:04 PM, Derek Chen-Becker
dchenbec...@gmail.comwrote:
Argh, that's what I was trying to say. No more posting after Midnight for
me :(
Folks,
We are all on the path to doing better development... but it's a journey,
not a destination. I like Greg's suggestion of thinking compositionally and
have myself been struggling to improve my compositional thinking. I like
Derek's responsiveness to the user community and improvements to his ways of
thinking. We are all being agile (in the best sense of the word.) We are
all being JIT. Let's continue to improve as coders and improve the Lift
code base and community.
Thanks,
David
On Wed, Jun 17, 2009 at 12:29 AM, Jorge Ortiz jorge.or...@gmail.comwrote:
In Derek's defense, it's not how objects in classes work but how Lift
RequestVars work. Scala objects in classes aren't global singletons, just
per-class-instance singletons. But a Lift ReuqestVar object in a class is
pretty much a global singleton (unless you do some hacking like Derek did).
--j
On Tue, Jun 16, 2009 at 11:14 PM, Derek Chen-Becker
dchenbec...@gmail.com wrote:
I agree that it's an issue. In my own defense, what I meant was not that
I didn't think people would use more than one DB. I actually have several
apps (not yet converted to Lift) that use 4 or more persistence units that
represent various legacy databases. Rather, I failed to realize the problem
that would arise from defining the EM factory as a singleton because when I
wrote that code I didn't fully understand how member objects on classes
worked. Other than that, I agree with your post :)
Derek
On Tue, Jun 16, 2009 at 5:38 PM, Meredith Gregory
lgreg.mered...@gmail.com wrote:
Derek,
soapbox
You have just demonstrated a process that i have been talking about for
the last 15 years. People have a blind spot when it comes to thinking
compositionally. They think -- almost to a person -- about god's eye view
solutions where there's only one of some key solution component. They don't
think about solutions that are composed of ... (wait for it)... solutions!
It takes some serious training to think compositionally. Compositional
solutions, however, are the only realistic way to scale. When solutions are
compositional, you can *de*compose. The db example is a case in point.
One of the most natural ways to scale data access is sharding and
partitioning -- which requires upfront machinery to support decomposition
of
the store.
Lest you feel bad, note that some of the best scientific minds of all
time have fallen prey to this blind spot. Newtonian physics as well as
Einstein's update to Newton's proposal is a non-compositional solution.
Quantum mechanics also exhibits compositional failures. This is why physics
is failing to find proposals that link theories of gravitation (essentially
large scale) to quantum mechanical theories of the other forces
(essentially
very small scale) -- the physical theories are non-compositional -- they
don't scale!
One of the real things functional programming has going for it is that
the basic model of computation underlying the means of structuring and
manipulating programs is compositional. That's why it is important to have
a
technology like Scala resting atop the incumbent execution model (JVM)
being
deployed on web-scale problems. Compositionality is the only way to tackle
applications at global scale.
/soapbox
Thanks for getting the fix to this problem in so quickly.
Best wishes,
--greg
On Tue, Jun 16, 2009 at 11:53 AM, Derek Chen-Becker
dchenbec...@gmail.com wrote:
Using multiple EMs was not something I had considered when I wrote
this. I think that I can modify the code to provide a __nameSalt def to
differentiate instances. Let me work on it and I'll have something soon.
Derek
On 6/16/09, Jean-Luc jlcane...@gmail.com wrote:
For your information, here is an extract of source code of
RequestVarEM :
Trait RequestVarEM extends ScalaEntityManager with ScalaEMFactory {
object emVar extends RequestVar[EntityManager](openEM()) { ... }
}
EntityManager is stored in the singleton emVar; so, all db access of
Model objects are made using the singleton emVar.
= trait RequestVarEM allow only one connection to a database within
the same HttpRequest context.
Jean-Luc
2009/6/15 Jean-Luc jlcane...@gmail.com
Hello,
I have two databases, db1 (a.k.a. Motorbike) and db2 (a.k.a.
Motorway) defined with RequestVarEM :
- object ModelDb1 extends LocalEMF(db1) with RequestVarEM //
Motorbike database
- object ModelDb2 extends LocalEMF(db2) with RequestVarEM //
Motorway database
I thought one could access to any databases independently from any
snippet as long as the correct Model object were used (ModelDb1 or
ModelDb2
for exemple) ; but when I access both databases from the same page, the
second database access issues a Named query not found exception.
I have two snippets, one to
[Lift] Re: Scala learning tool
I think that there's talk in 2.8 of having tab completion or something similar in the REPL. Derek On Tue, Jun 16, 2009 at 9:23 PM, g-man gregor...@gmail.com wrote: All the Scala books and tutorials recommend using the Scala interactive shell to set up scenarios and learn how Scala works. I agree, but my problem was the (apparent) lack of something like Python's dir(object) call, which gives you all the 'names' available; Ruby and Erlang have similar commands, but not, as far as I know, Scala. I did find a little script that does just that at: http://lousycoder.com/blog/index.php?/archives/91-Scala-Querying-an-objects-fields-and-methods-with-reflection.html with the source at: http://gist.github.com/87519 I compiled it, and when I import it, it works just dandy: scala import ScalaReflection._ import ScalaReflection._ scala 3.methods__ hashCode reverseBytes(int) compareTo(Object) compareTo(Integer) equals(Object) toString(int,int) toString(int) ... scala 3.fields__ MIN_VALUE MAX_VALUE TYPE digits DigitTens DigitOnes sizeTable value SIZE serialVersionUID Perhaps there is something like this already built-in to Scala, but I can't find it... if not, it may be worthwhile adding. Now, what I want to know is: is there a way to load an actual Lift session into the interactive command interpreter, so I can create and check out out functions, etc? I remember doing that with Ruby and Rails back in the day. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Thoughts on separation of display from logic
This reminds me somewhat of the Wicket approach, which would use a namespaced attribute of the textarea tag to inform the binding logic. I've been wanting to keep the styling of my lift-generated tags in the markup as well, so maybe I'll toy a bit with creating a version of bind() and the form generator functions that would allow this. Kris On Wed, Jun 17, 2009 at 11:22 AM, Matt Williamsm...@makeable.co.uk wrote: I wholeheartedly agree with the philosophy of separating the display from the program logic, and am currently getting to grips with the generators, but am finding that now I end up with a degree of markup within my code. Can you think of any caveats to infering the node type passed, and dynamically using the relevant generators to construct the returned node. I am thinking something along the lines of: person:biography textarea style=myStyle cols=20 rows=5 This is a sample of some biography text /textarea /person:biography Where it would automatically infer that it is a textarea, pass through the relevant attributes, and insert whatever function, values, etc I have specified in my snippet. What are your thoughts on this? Brgds, Matt --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Scala learning tool
On Wed, Jun 17, 2009 at 1:41 PM, Derek Chen-Becker dchenbec...@gmail.comwrote: I think that there's talk in 2.8 of having tab completion or something similar in the REPL. It's far more than talk. Paul has it nailed. 2.8 will offer a much better REPL experience. Derek On Tue, Jun 16, 2009 at 9:23 PM, g-man gregor...@gmail.com wrote: All the Scala books and tutorials recommend using the Scala interactive shell to set up scenarios and learn how Scala works. I agree, but my problem was the (apparent) lack of something like Python's dir(object) call, which gives you all the 'names' available; Ruby and Erlang have similar commands, but not, as far as I know, Scala. I did find a little script that does just that at: http://lousycoder.com/blog/index.php?/archives/91-Scala-Querying-an-objects-fields-and-methods-with-reflection.html with the source at: http://gist.github.com/87519 I compiled it, and when I import it, it works just dandy: scala import ScalaReflection._ import ScalaReflection._ scala 3.methods__ hashCode reverseBytes(int) compareTo(Object) compareTo(Integer) equals(Object) toString(int,int) toString(int) ... scala 3.fields__ MIN_VALUE MAX_VALUE TYPE digits DigitTens DigitOnes sizeTable value SIZE serialVersionUID Perhaps there is something like this already built-in to Scala, but I can't find it... if not, it may be worthwhile adding. Now, what I want to know is: is there a way to load an actual Lift session into the interactive command interpreter, so I can create and check out out functions, etc? I remember doing that with Ruby and Rails back in the day. -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Thoughts on separation of display from logic
I can see a set of methods that look like: textarea(f: String = Unit)(n: NodeSeq) that will slurp the values and attributes out of the NodeSeq... so you'd bind like: biography - textarea(s = setBio(s)) _ On Wed, Jun 17, 2009 at 10:22 AM, Matt Williams m...@makeable.co.uk wrote: I wholeheartedly agree with the philosophy of separating the display from the program logic, and am currently getting to grips with the generators, but am finding that now I end up with a degree of markup within my code. Can you think of any caveats to infering the node type passed, and dynamically using the relevant generators to construct the returned node. I am thinking something along the lines of: person:biography textarea style=myStyle cols=20 rows=5 This is a sample of some biography text /textarea /person:biography Where it would automatically infer that it is a textarea, pass through the relevant attributes, and insert whatever function, values, etc I have specified in my snippet. What are your thoughts on this? Brgds, Matt -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Lift + Javeline
Just 2.1 version ... we'll try that out. It's still a mystery because offline example works but wen putting it in lift fails only on FF. So far there is no indication that Lift is doing anything wrong. Br's, Marius On Jun 17, 4:14 pm, Matt Williams m...@makeable.co.uk wrote: Are you using the latest version from the repository? There were a few firefox fixes put in place a week or so ago. On Jun 17, 1:18 pm, Marius marius.dan...@gmail.com wrote: Hi all, We've been trying javeline (http://ajax.org/) with Lift and it's pretty needless to say how cool it is. It seems to work fine in Chrome, IE6/7, Safari but we're getting a strange JS error on FF3 only. Seehttp://scalaliftapp.appspot.com/example2... or FF3 we're getting this.oDrag is null JS error. Did anyone experience this before? Br's, Marius --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Thoughts on separation of display from logic
We'd still need some attribute to disambiguate in the case of multiple textarea tags, wouldn't we? Kris On Wed, Jun 17, 2009 at 2:51 PM, David Pollakfeeder.of.the.be...@gmail.com wrote: I can see a set of methods that look like: textarea(f: String = Unit)(n: NodeSeq) that will slurp the values and attributes out of the NodeSeq... so you'd bind like: biography - textarea(s = setBio(s)) _ On Wed, Jun 17, 2009 at 10:22 AM, Matt Williams m...@makeable.co.uk wrote: I wholeheartedly agree with the philosophy of separating the display from the program logic, and am currently getting to grips with the generators, but am finding that now I end up with a degree of markup within my code. Can you think of any caveats to infering the node type passed, and dynamically using the relevant generators to construct the returned node. I am thinking something along the lines of: person:biography textarea style=myStyle cols=20 rows=5 This is a sample of some biography text /textarea /person:biography Where it would automatically infer that it is a textarea, pass through the relevant attributes, and insert whatever function, values, etc I have specified in my snippet. What are your thoughts on this? Brgds, Matt -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Lift + Javeline
Maybe an issue with the compressor? (although i dont see why that would just affect firefox) On Wed, 2009-06-17 at 14:00 -0700, marius d. wrote: Just 2.1 version ... we'll try that out. It's still a mystery because offline example works but wen putting it in lift fails only on FF. So far there is no indication that Lift is doing anything wrong. Br's, Marius On Jun 17, 4:14 pm, Matt Williams m...@makeable.co.uk wrote: Are you using the latest version from the repository? There were a few firefox fixes put in place a week or so ago. On Jun 17, 1:18 pm, Marius marius.dan...@gmail.com wrote: Hi all, We've been trying javeline (http://ajax.org/) with Lift and it's pretty needless to say how cool it is. It seems to work fine in Chrome, IE6/7, Safari but we're getting a strange JS error on FF3 only. Seehttp://scalaliftapp.appspot.com/example2... or FF3 we're getting this.oDrag is null JS error. Did anyone experience this before? Br's, Marius --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Thoughts on separation of display from logic
On Wed, Jun 17, 2009 at 2:07 PM, Kris Nuttycombe kris.nuttyco...@gmail.comwrote: We'd still need some attribute to disambiguate in the case of multiple textarea tags, wouldn't we? I don't think so. The only NodeSeq being passed to the function is the NodeSeq inside the tag that's getting bound to. Kris On Wed, Jun 17, 2009 at 2:51 PM, David Pollakfeeder.of.the.be...@gmail.com wrote: I can see a set of methods that look like: textarea(f: String = Unit)(n: NodeSeq) that will slurp the values and attributes out of the NodeSeq... so you'd bind like: biography - textarea(s = setBio(s)) _ On Wed, Jun 17, 2009 at 10:22 AM, Matt Williams m...@makeable.co.uk wrote: I wholeheartedly agree with the philosophy of separating the display from the program logic, and am currently getting to grips with the generators, but am finding that now I end up with a degree of markup within my code. Can you think of any caveats to infering the node type passed, and dynamically using the relevant generators to construct the returned node. I am thinking something along the lines of: person:biography textarea style=myStyle cols=20 rows=5 This is a sample of some biography text /textarea /person:biography Where it would automatically infer that it is a textarea, pass through the relevant attributes, and insert whatever function, values, etc I have specified in my snippet. What are your thoughts on this? Brgds, Matt -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Sitemap Base URL
Im currently working on porting a CMS built in rails over to lift. Im finding the sitemap very handy for use in the administration area, which will be located at /admin/, but for the rest of the site, we will be using a dynamic navigation constructed from the database on a requested hostname basis. By using a sitemap, am I preventing the access to urls not defined within the sitemap? If so, how do I overcome this behaviour, or can I set the sitemap to only have scope to a baseuri of /admin/ Kind Regards, Matt --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Sitemap Base URL
Matt, I posted some code a week or so ago in response to Glenn's request to have menu items dynamically built from RDBMS queries. Please take a look at http://groups.google.com/group/liftweb/browse_thread/thread/3b0e3611bc316f71# Thanks, David PS -- This should not be construed as an RTFM post... I just want to unify the threads so we can share common knowledge and maybe you and Glenn and other can collaborate. On Wed, Jun 17, 2009 at 2:17 PM, Matt Williams m...@makeable.co.uk wrote: Im currently working on porting a CMS built in rails over to lift. Im finding the sitemap very handy for use in the administration area, which will be located at /admin/, but for the rest of the site, we will be using a dynamic navigation constructed from the database on a requested hostname basis. By using a sitemap, am I preventing the access to urls not defined within the sitemap? If so, how do I overcome this behaviour, or can I set the sitemap to only have scope to a baseuri of /admin/ Kind Regards, Matt -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Trivially Set Mapper Scope
User.addlQueryParams.set(By(User.firstname, david) :: User.addlQueryParams.is) It's a request var so it's set on a request by request basis. On Wed, Jun 17, 2009 at 10:05 AM, Matt Williams m...@makeable.co.uk wrote: Is there a simple way that I can set the record scope on a mapper. For example, if I want to specify a WHERE clause for every query to the database, how would I do this? In my particular case, I want to set the scope based upon the hostname used to service the request, but other usages may involve soft record deletion, etc. Kind Regards, Matt -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Trivially Set Mapper Scope
Thank you VERY much! Kind Regards, Matt On Wed, 2009-06-17 at 14:42 -0700, David Pollak wrote: User.addlQueryParams.set(By(User.firstname, david) :: User.addlQueryParams.is) It's a request var so it's set on a request by request basis. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
Tim, LOL! Derek, i'm amazed at all the good work you've done on lift. You're unstoppable! i trust that all understood i was having good fun. Best wishes, --greg On Wed, Jun 17, 2009 at 2:07 AM, TSP tim.pig...@optrak.co.uk wrote: In my own defense ... failed to realize the problem that would arise from defining the EM factory as a singleton Are you being honest here Derek? Was not the real problem that you failed to truly embrace the shape of the paradoxical combinator? -- L.G. Meredith Managing Partner Biosimilarity LLC 1219 NW 83rd St Seattle, WA 98117 +1 206.650.3740 http://biosimilarity.blogspot.com --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] what does 'S' stand for?
In the files S.scala and SHtml.scala, it's kind of hard to figure out what S means. Session? Simple? Structured? Scala? SomethingElse? Thanks, Eric -- Eric Bowman Boboco Ltd ebow...@boboco.ie http://www.boboco.ie/ebowman/pubkey.pgp +35318394189/+353872801532 --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Thoughts on separation of display from logic
One possibility I already considered is something like: bind(nodeseq, prefix, suffix - Text(matched an element), @suffix - Text(matched an attribute), @suffix=value - Text(matched an attribute with specified value)); the bindings here would respectively match the elements: prefix:suffixcontent/prefix:suffix span prefix:suffix=placeholdercontent/span span prefix:suffix=valuecontent/span Use of the span elements above was an arbitrary choice What's missing is an intuitive way to access the node that has been bound, especially if you only want to change the contents On Wed, Jun 17, 2009 at 10:19 PM, David Pollak feeder.of.the.be...@gmail.com wrote: On Wed, Jun 17, 2009 at 2:07 PM, Kris Nuttycombe kris.nuttyco...@gmail.com wrote: We'd still need some attribute to disambiguate in the case of multiple textarea tags, wouldn't we? I don't think so. The only NodeSeq being passed to the function is the NodeSeq inside the tag that's getting bound to. Kris On Wed, Jun 17, 2009 at 2:51 PM, David Pollakfeeder.of.the.be...@gmail.com wrote: I can see a set of methods that look like: textarea(f: String = Unit)(n: NodeSeq) that will slurp the values and attributes out of the NodeSeq... so you'd bind like: biography - textarea(s = setBio(s)) _ On Wed, Jun 17, 2009 at 10:22 AM, Matt Williams m...@makeable.co.uk wrote: I wholeheartedly agree with the philosophy of separating the display from the program logic, and am currently getting to grips with the generators, but am finding that now I end up with a degree of markup within my code. Can you think of any caveats to infering the node type passed, and dynamically using the relevant generators to construct the returned node. I am thinking something along the lines of: person:biography textarea style=myStyle cols=20 rows=5 This is a sample of some biography text /textarea /person:biography Where it would automatically infer that it is a textarea, pass through the relevant attributes, and insert whatever function, values, etc I have specified in my snippet. What are your thoughts on this? Brgds, Matt -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: what does 'S' stand for?
It stands for State. When I first started coding Lift, I was using emacs and wanted to have short names for everything... especially the commonly used stuff. I wanted to isolate state into a single place so every time you dealt with S, you know you were doing something stateful (rather than purely functional with no side effects... with the exception of RDBMS related stuff which is stateful on its face.) S has morphed into S, SHtml, RequestVars and SessionVars... but all the explicit state is still kept in S. Does that help? Thanks, David On Wed, Jun 17, 2009 at 3:35 PM, Eric Bowman ebow...@boboco.ie wrote: In the files S.scala and SHtml.scala, it's kind of hard to figure out what S means. Session? Simple? Structured? Scala? SomethingElse? Thanks, Eric -- Eric Bowman Boboco Ltd ebow...@boboco.ie http://www.boboco.ie/ebowman/pubkey.pgp +35318394189/+353872801532 -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
i trust that all understood i was having good fun. The only thing I understood is that there are some people out there vastly more knowledgeable than myself! :D Brgds, Matt --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Thoughts on separation of display from logic
Crud... adding xpathisms to bind... where will it end? :-) On Wed, Jun 17, 2009 at 3:41 PM, Kevin Wright kev.lee.wri...@googlemail.com wrote: One possibility I already considered is something like: bind(nodeseq, prefix, suffix - Text(matched an element), @suffix - Text(matched an attribute), @suffix=value - Text(matched an attribute with specified value)); the bindings here would respectively match the elements: prefix:suffixcontent/prefix:suffix span prefix:suffix=placeholdercontent/span span prefix:suffix=valuecontent/span Use of the span elements above was an arbitrary choice What's missing is an intuitive way to access the node that has been bound, especially if you only want to change the contents On Wed, Jun 17, 2009 at 10:19 PM, David Pollak feeder.of.the.be...@gmail.com wrote: On Wed, Jun 17, 2009 at 2:07 PM, Kris Nuttycombe kris.nuttyco...@gmail.com wrote: We'd still need some attribute to disambiguate in the case of multiple textarea tags, wouldn't we? I don't think so. The only NodeSeq being passed to the function is the NodeSeq inside the tag that's getting bound to. Kris On Wed, Jun 17, 2009 at 2:51 PM, David Pollakfeeder.of.the.be...@gmail.com wrote: I can see a set of methods that look like: textarea(f: String = Unit)(n: NodeSeq) that will slurp the values and attributes out of the NodeSeq... so you'd bind like: biography - textarea(s = setBio(s)) _ On Wed, Jun 17, 2009 at 10:22 AM, Matt Williams m...@makeable.co.uk wrote: I wholeheartedly agree with the philosophy of separating the display from the program logic, and am currently getting to grips with the generators, but am finding that now I end up with a degree of markup within my code. Can you think of any caveats to infering the node type passed, and dynamically using the relevant generators to construct the returned node. I am thinking something along the lines of: person:biography textarea style=myStyle cols=20 rows=5 This is a sample of some biography text /textarea /person:biography Where it would automatically infer that it is a textarea, pass through the relevant attributes, and insert whatever function, values, etc I have specified in my snippet. What are your thoughts on this? Brgds, Matt -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: what does 'S' stand for?
David Pollak wrote: It stands for State. When I first started coding Lift, I was using emacs and wanted to have short names for everything... especially the commonly used stuff. I wanted to isolate state into a single place so every time you dealt with S, you know you were doing something stateful (rather than purely functional with no side effects... with the exception of RDBMS related stuff which is stateful on its face.) S has morphed into S, SHtml, RequestVars and SessionVars... but all the explicit state is still kept in S. Does that help? Yeah, muchly, thanks. That might be a nice thing to put in a comment in S.scala... -- Eric Bowman Boboco Ltd ebow...@boboco.ie http://www.boboco.ie/ebowman/pubkey.pgp +35318394189/+353872801532 --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Combined Lift/Servlet and initialization
Given the combination of a lift powered webapp and an existing servlet I like to use lift's marvellous mapper in the latter. Do I need to ensure that lift (i.e. db and Schemifier) is initialized before the servlet starts serving requests, or is this implied by some servlet specification? If it needs to be done manually, what would be the right procedure? There is LiftRules.doneBoot being set after initialization, but it is private. Thanks in advance Andreas --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] QA, before merging code
Hi, Seems theres been a little bit of discussion about methodologies of coding and development processes in the latest threads which is cool and makes me think about my current coding efforts. I created a branch a while ago where I put in my take on a slightly alternative (or complementary?) binding process (the particular code adds a bind by name to BindHelpers). I was hoping for some feedback from a few of you (David, Marius, and anyone else) before merging it back with the main site, as I feel what I have done might be contentious and I don't want to cause any problems. Whats the normal process of committing changes. Is the code QA'ed in some way or do I just do it,and wait for people to say #!. cheers Oliver --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
2009/6/18 Meredith Gregory lgreg.mered...@gmail.com Oliver, The short answer is no. The longer answer is - i worked this all out on my own; so, you guys -- who can program lift on top of scala on top of JVM and are therefore about 20X smarter than i am -- can too. I think if we were all 20X (or 2X) smarter than you, we would have taken over Google by now. - - And also, help is always available, if there is something specific you don't understand, let me know and i will do my best to convey it to you. As suggested by another kind person, I may have to start by going back to (an American?) school. Heres a question, why should I care about Monad's when they are already in OO, just not called Monads? - Best wishes, --greg P.S. Here is a version of the paragraph with links to useful bits of lore from the literature. For myself, i was unhappy with the notion of name. The π-calculihttp://en.wikipedia.org/wiki/Pi-calculusand lambda calculi http://en.wikipedia.org/wiki/Lambda_calculus suffer a dependence on a notion of name. Both families of calculi require at least countably infinitely http://en.wikipedia.org/wiki/Countable many nameshttp://www.cs.nps.navy.mil/research/languages/statements/gordon.html, and a notion of equality on names. If names have no internal structure then these theories *cannot be effectivehttp://en.wikipedia.org/wiki/Computable_function *. The reasons is that the notion of equality must then be realized as an infinitary table which cannot fit in any computer we have access to. Therefore, in effective theories, names must have internal structure. Since they have internal structure and are at least countably infinite, one is in danger of undermining the foundational character of these proposals for computing. Therefore, the only possible solution is that the notion of structured name must come from the notion of program proposed by the model. This argument is airtight. If you want a foundational model of computing with nominal structure, the nominal structure must derive from the notion of computation being put forward, i.e. it must *reflect* the notion of computationhttp://svn.biosimilarity.com/src/open/papers/trunk/concurrency/rho/ex_nihilo_entcs/ex_nihilo_finco.pdf. This gives rise to all kinds of new an beautiful phenomena. One measure of your way into compositional thinking is whether this is happening. Is your approach to compositional thinking beginning to yield whole new aspects of computing, and new 'wholes' of computation, new forms of organization. 2009/6/16 Oliver Lambert olambo...@gmail.com 2009/6/17 Meredith Gregory lgreg.mered...@gmail.com Jeremy, Most excellent question award to you, sir! How to bootstrap thinking compositionally... this is what i did - learn some compositional idioms by heart - do you know the shape of the paradoxical combinator by heart - do you know the data making up a monad - do you know the data making up a distributive law between monads - use them in real world applications and see where they fail - when is calculating the least/greatest fixpoint of a recursive spec for a problem the suboptimal solution - when is a monad not the answer - when is an indexed form of composition inadequate - improve them - is it a situational improvement or - a fundamental improvement - see where the very programming model itself fails - is functional composition the only sort of composition - how is parallel composition like functional composition - is parallel composition easily represented in categorical composition - improve it - what is the view of the world in your notion of composition - play with new programming models - does your new notion of composition give rise to a whole generation of different models - invent new idioms in these models - what are the things these models naturally express - and teach them to someone who wishes to bootstrap thinking compositionally For myself, i was unhappy with the notion of name. The π-calculi and lambda calculi suffer a dependence on a notion of name. Both families of calculi require at least countably infinitely many names, and a notion of equality on names. If names have no internal structure then these theories *cannot be effective*. Do we need to do some sort of course to understand this language? The reasons is that the notion of equality must then be realized as an infinitary table which cannot fit in any computer we have access to. Therefore, in effective theories, names must have internal structure. Since they have internal structure and are at least countably infinite, one is in danger of undermining the foundational character of these proposals for computing. Therefore, the only possible solution is that the notion of structured
[Lift] MEMDEBUG failure
I don't know whether this is a Scala problem or a Llift one, so I'll post this problem here with apologies if it's a Scala issue. I keep getting the following error message since I upgraded to Scala 1.7.5. This pops up in my console every 5 seconds, the default jetty scan interval in the pom. I'm using a MySQL database instead of embedded derby, if that makes a difference? ERROR - [MEMDEBUG] failure java.lang.NoSuchFieldException: refSet at java.lang.Class.getDeclaredField(Class.java:1882) at net.liftweb.http.PointlessActorToWorkAroundBug$$anonfun$act$1$ $anonfun$apply$1.apply(LiftServlet.scala:715) at net.liftweb.http.PointlessActorToWorkAroundBug$$anonfun$act$1$ $anonfun$apply$1.apply(LiftServlet.scala:707) at scala.actors.Reaction.run(Reaction.scala:78) at net.liftweb.http.ActorSchedulerFixer$$anon$1$$anonfun$execute $1.apply(LiftServlet.scala:668) at net.liftweb.http.ActorSchedulerFixer$$anon$1$$anonfun$execute $1.apply(LiftServlet.scala:668) at net.liftweb.http.ActorSchedulerFixer$$anonfun$20$$anon$2.run (LiftServlet.scala:626) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask (ThreadPoolExecutor.java:885) at java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:907) at java.lang.Thread.run(Thread.java:619) --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: MEMDEBUG failure
Glenn, We have not moved Lift to Scala 2.7.5. It's about a day's worth of work for me to verify that the Actor fixes actually fix things. Please stick with Scala 2.7.4. Thanks, David On Wed, Jun 17, 2009 at 5:13 PM, glenn gl...@exmbly.com wrote: I don't know whether this is a Scala problem or a Llift one, so I'll post this problem here with apologies if it's a Scala issue. I keep getting the following error message since I upgraded to Scala 1.7.5. This pops up in my console every 5 seconds, the default jetty scan interval in the pom. I'm using a MySQL database instead of embedded derby, if that makes a difference? ERROR - [MEMDEBUG] failure java.lang.NoSuchFieldException: refSet at java.lang.Class.getDeclaredField(Class.java:1882) at net.liftweb.http.PointlessActorToWorkAroundBug$$anonfun$act$1$ $anonfun$apply$1.apply(LiftServlet.scala:715) at net.liftweb.http.PointlessActorToWorkAroundBug$$anonfun$act$1$ $anonfun$apply$1.apply(LiftServlet.scala:707) at scala.actors.Reaction.run(Reaction.scala:78) at net.liftweb.http.ActorSchedulerFixer$$anon$1$$anonfun$execute $1.apply(LiftServlet.scala:668) at net.liftweb.http.ActorSchedulerFixer$$anon$1$$anonfun$execute $1.apply(LiftServlet.scala:668) at net.liftweb.http.ActorSchedulerFixer$$anonfun$20$$anon$2.run (LiftServlet.scala:626) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask (ThreadPoolExecutor.java:885) at java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:907) at java.lang.Thread.run(Thread.java:619) -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] SOME FAMOUS COLLECTIONS
SOME FAMOUS COLLECTIONS http://nicesubramani.blogspot.com http://nicesubramani.blogspot.com http://nicesubramani.blogspot.com --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: scalajpa - while accessing two distincts databases, the second access is made with a connection to the first database
Oliver,
Objects and monads are really not the same. At it's heart the concept of
monad is an appropriately parametric notion of composition. If you have any
experience with abstract algebra, you might recognize that the notion of a
group http://en.wikipedia.org/wiki/Symmetry_group is an appropriately
parametric notion of symmetry. Groups give an exceptionally well abstracted
account of symmetry. Monads give an exceptionally well abstracted notion of
composition. This is a lot easier to see in the Category Theoretic
presentation.
A monad http://en.wikipedia.org/wiki/Monad_%28category_theory%29 is
presented by three pieces of data:
- An endofunctor http://en.wikipedia.org/wiki/Functor M : C - C
(intuitively, think of M as a parametric type constructor and C as the
universe of types and maps)
- A natural
transformationhttp://en.wikipedia.org/wiki/Natural_transformationunit:
Id - M -- this is a higher-order critter: it takes maps to maps; but
i'll give you a metaphor in just a moment.
- A natural transformation mult: M^2 - M
One picture you can have in your mind is M is a kind of box factory. Then
unit says how you can put things into a box, and mult says how you can
flatten nested boxes into an ordinary box (this is the origins of flatMap in
Scala's presentation). Another way of understanding this is that M is a kind
of higher-order compositor, i.e. a way of combining things just like
multiplication, as in a*b, is a way of combining things. Then the unit is
the analog of having a unit for your multiplication and mult is the analog
of an associativity law ( a*(b*c) = (a*b)*c ). These line up with the box
analogy more easily if you write things with prefix notation instead of
infix notation.
- Let's write {*| a, b |*} instead of a*b. The reason we adopt this more
verbose notation is that we can note the different kind of boxes with the
'color' of the braces. M-colored braces, {M| a, b |M}, are associated with
an M-box.
- Then unit( a ) = {M| a |M}, it puts a in an M-box. This has an
alternate presentation of the form {M| |M}.{M| a |M} = {M| a |M}. i mention
it to point out the analogy with the binary operation _*_, but it muddies
the water a little with begging the question about the _._. So, i will just
leave it -- without explanation -- for you to explore.
- And mult( {M| {M| a11, ..., a1J |M} ... {M| aI1, ... aIJ' |M} |M} ) =
{M| a11, ..., aIJ' |M}. It tells you how to canonically flatten M-boxes.
This functions as an association because if boxes canonically flatten, then
{M| a, {M| b, c |M} |M} = {M| a, b, c |M} = {M| {M| a, b |M}, c |M}.
The apparent lexical connection between this way of thinking about things
and XML *is not accidental*. Monads can be viewed as colored braces, aka
matched tags. Monads are a semantical creature that presents syntactically
like XML.
This way of thinking about things is really different from objects. To be
sure, there are notions of objects that are universal and so can be made to
fit or encode just about anything; but, that doesn't mean the encodings are
nice, or scalable or maintainable. You have only to to look at something
like LINQ -- which is really just a presentation of monads -- to see just
how flexible and yet compact the monadic way of structuring composition is.
Specifically, both set-comprehension notation and SELECT-FROM-WHERE, when
interpreted polymorphically, provide a natural representation of the monad.
- { pattern | t1 - generator1, ..., tn - generatorN, constraint1, ...,
constraintK }
- SELECT pattern FROM generator WHERE constraint
Those to pieces of computational machinery have very simple, and natural
mappings to the monad operations. You will win if you work these out for
yourself. Phil Wadler has excellent papers to provide cheat sheets. The
Scala for-comprehension and the corresponding operations of map, flatMap and
filter are also excellent cheat sheets. But, you get the joy if you work
this out for yourself.
Best wishes,
--greg
2009/6/17 Oliver Lambert olambo...@gmail.com
2009/6/18 Meredith Gregory lgreg.mered...@gmail.com
Oliver,
The short answer is no. The longer answer is
- i worked this all out on my own; so, you guys -- who can program
lift on top of scala on top of JVM and are therefore about 20X smarter
than
i am -- can too.
I think if we were all 20X (or 2X) smarter than you, we would have taken
over Google by now.
- And also, help is always available, if there is something specific
you don't understand, let me know and i will do my best to convey it to
you.
As suggested by another kind person, I may have to start by going back to
(an American?) school.
Heres a question, why should I care about Monad's when they are already in
OO, just not called Monads?
-
Best wishes,
--greg
P.S. Here is a version of the paragraph with links to useful bits of lore
from the literature.
For myself, i was unhappy with
[Lift] Re: Mapper record deletion
Thanks, I'm working on it.
It seems, after reading the Lift book, since we have 'Alert' in the
list of basic JsCmds in Table 8.2, a companion 'Confirm' (and perhaps
even 'Prompt') command would be logical to have, since these are basic
and popular user interface elements.
On Jun 16, 6:46 am, Magnus Alvestad magnus.alves...@gmail.com wrote:
As I move deeper into learning Lift, I now want to start deleting
Mapper records in the ToDo example.
Here's how I did it (based on suggestions in this group, I think):
bind ( question, html,
text - ..,
delete - ajaxButton(Text(Remove),
Call(dialog, Str(Do you want to delete the question?)),
() = {q.delete_!; S.notice( Deleted the question!); reDraw
()})
)
.. and then in the template (default.html) ..
script type=javascript
function dialog(text, theCall) {
if (confirm(text)) theCall();
}
/script
-Magnus
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[Lift] Re: Combined Lift/Servlet and initialization
Andreas, As long as the LiftServlet is in your web.xml file, all should work correctly. Thanks, David On Wed, Jun 17, 2009 at 4:53 PM, Andreas B and...@gmx.net wrote: Given the combination of a lift powered webapp and an existing servlet I like to use lift's marvellous mapper in the latter. Do I need to ensure that lift (i.e. db and Schemifier) is initialized before the servlet starts serving requests, or is this implied by some servlet specification? If it needs to be done manually, what would be the right procedure? There is LiftRules.doneBoot being set after initialization, but it is private. Thanks in advance Andreas -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: QA, before merging code
On Wed, Jun 17, 2009 at 5:00 PM, Oliver Lambert olambo...@gmail.com wrote: Hi, Seems theres been a little bit of discussion about methodologies of coding and development processes in the latest threads which is cool and makes me think about my current coding efforts. I created a branch a while ago where I put in my take on a slightly alternative (or complementary?) binding process (the particular code adds a bind by name to BindHelpers). I was hoping for some feedback from a few of you (David, Marius, and anyone else) before merging it back with the main site, as I feel what I have done might be contentious and I don't want to cause any problems. Generally, let me or Marius or Derek or one of the other been around Lift for a while guys take a look at the code. Then check it into the main branch and let people give you feedback. Please make sure to do a mvn clean install before pushing code to make sure all compiles and passes tests. Whats the normal process of committing changes. Is the code QA'ed in some way or do I just do it,and wait for people to say #!. cheers Oliver -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: simple syntax question
If you have XML like: input my:id=foo/
you can:
bind(my, xml, FuncAttrBindParam(id, nodeseq = nodeseq ++ Text(bar),
id))
And you get:
input id=foobar/
On Wed, Jun 17, 2009 at 10:21 AM, DavidV david.v.villa...@gmail.com wrote:
For now I have fixed the problem by calling a new method in my snippet
that accesses the variable with { } in the input tag. I would be
interested to know if there is a way to do this with a bind tag
directly in the input tag in the .html file, because I feel like my
current solution is a bit of a kludge...
-David
On Jun 17, 12:00 pm, DavidV david.v.villa...@gmail.com wrote:
I would like to include a variable value in an input tag in my .html
file. I have defined a tag as follows:
def upload(xhtml: Group): NodeSeq =
if (S.get_?) {
bind(ul, chooseTemplate(choose, get, xhtml),
file_upload - fileUpload(ul = theUpload(Full
(ul))),
batch - currBatch
)
}
thus,
choose:get
ul:batch/
/choose:get
returns the variable value that I need
How can I retrieve this variable for the value= attribute of my
input tag? For instance, right now I am trying to do it like this:
input name=batch type=hidden value=ul:batch/ /
but that is not working. It also doesn't work like this:
input name=batch type=hidden value=ul:batch/ /
Thanks,
David
--
Lift, the simply functional web framework http://liftweb.net
Beginning Scala http://www.apress.com/book/view/1430219890
Follow me: http://twitter.com/dpp
Git some: http://github.com/dpp
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