On Jan 18, 2010, at 3:54 PM, Anca Luca wrote: We need to define the names we're going to use first so I'm putting a -1 to block till we define them. -1 for b) since - we would need to recode resolvers, serializers and a data object to hold the data, basically redoing everything I've done for References. - it would make a not nice API +0 for a) -0 Right now all our resolvers never throw an exception. I'd like to keep them like this as much as possible.

I don't think it's valid. What would wiki:Space.Page^className#property mean?

What is the reason? So that object names don't move when objects are added/removed?

I don't know enough but +0 for iii) or iv). Thanks -Vincent _______________________________________________ devs mailing list devs(a)xwiki.org http://lists.xwiki.org/mailman/listinfo/devs

On 01/18/2010 05:54 PM, Anca Luca wrote: Actually on second thought, if we want always parsable references, we need to also find out how to resolve a string with no ^ and/or # separators as Object, respective Property.

A 'current' resolver could resolve "FooBar" as: - currentDocRef^FooBar when of type object (the object (as per ii, iii or iv) of type FooBar in the current document, as resolved by the CurrentStringDocumentReferenceResolver resolver) - currentDocRef^currentDocRef#FooBar when of type property (the property FooBar in the current document (as resolved by the CurrentStringDocumentReferenceResolver resolver), of the object (as per ii, iii or iv) of the class defined by the document reference) In similar manner, a 'default' resolver could resolve "FooBar" as: - defaultDocRef^FooBar when of type object - defaultDocRef^defaultClass#FooBar when of type property (where defaultClass is either defaultDocRef (see above) or a different class, which we agree to be the default) Also, a string like wiki:Space.Page#prop parsed as object would have to be interpreted as 'FooBar' above, and parsed as property, would have the property specified as "prop" of the object obtained by parsing 'wiki:Space.Page" as 'FooBar' above. WDYT? (I hope I didn't mess it up, I know it's complicated, but it has to make sense.) Actually, if we add new types for this, then we still have to find a way to interpret wiki:Space.Page^className as Object or Property (since everything has to make sense as everything), which brigs us in a bit of a loop. If considering as invalid is harder than parsing, I go for this one: +1 Thanks, Anca >> >>> iv) a shortcut for wiki:Space.Page^className[0] (which, note, does not >>> necessarily mean the first object in that document, since indexing of objs in a >>> document is not recomputed when objects are deleted). >> >> What is the reason? So that object names don't move when objects are added/removed? > > yes, because they are identified by their index. > >> >> I don't know enough but +0 for iii) or iv). >> >> Thanks >> -Vincent >> >>> WDYT? >>> >>> Thanks, >>> Anca >>> >>> On 01/13/2010 02:42 PM, Anca Luca wrote: >>>> Hi devs, >>>> >>>> Short story: >>>> 1/ add the CLASS, OBJECT, PROPERTY EntityTypes in the model >>>> >>>> +1 >>>> >>>> 2/ serialization for referencing a property of an object >>>> a) wiki:Space.Page^className[objectNumber]#property >>>> b) wiki:Space.Page^className#objectNumber$property >>>> +0.75 for b) >>>> >>>> Long story: >>>> >>>> 1/ I would need to extend the EntityReference to be able to target a >>>> property in an object in a document. >>>> For this, I will need to add >>>> >>>> /** >>>> * Represents a Class Entity >>>> */ >>>> CLASS, >>>> >>>> /** >>>> * Represents an Object Entity. >>>> */ >>>> OBJECT, >>>> >>>> /** >>>> * Represents a Property Entity >>>> */ >>>> PROPERTY, >>>> >>>> in the EntityType. Although I would prefer an extensible framework that >>>> would allow to extend the possible entity types without changing an enum >>>> in the platform (for any API user to be able to define its own >>>> references), I think this is fairly extensible (these are key concepts >>>> in the xwiki model and I don't think they would be changed that soon, >>>> and their interpretation is flexible, they could be combined with any >>>> parent to generate either references to class definitions or instances). >>>> here's my +1 for this. >>>> >>>> 2/ I would also need a 'standard' string serialization for these. Now, >>>> there's also the option to do it in my own module (annotations) because >>>> only I need it ftm, but I prefer to have a platform wide approach. Opinions? >>>> There are 2 choices, with a potentially different combination of separators: >>>> >>>> a/ wiki:Space.Page^className[objectNumber]#property >>>> >>>> pros: it's a suggestive way to access objects by number ([] is the >>>> standard syntax for array indexed access and the objects are accessed by >>>> index), [] is supported by JCR so maybe we should support it too >>>> cons: [] is somewhat inconsistent with all other separators which are >>>> just one separator, to the left (right) of the entity, harder to >>>> implement the [] separators on the current framework >>>> >>>> b/ wiki:Space.Page^className#objectNumber$property >>>> >>>> pros: inline with the separator usage we already have (and easier to >>>> implement for this reason), could be easier refactored to contain an >>>> object name instead of the number >>>> cons: $ separator can collide with velocity syntax (can potentially >>>> cause trouble when used in velocity -- an alternative could be the pipe >>>> |), could be harder to drop the object number part of the reference to >>>> refer a property in a class (if wanted, in the future) >>>> >>>> I have no other argument between a) and b) but the implementation speed >>>> one, so I'd go for a b)-like approach, in the spirit of the current >>>> separators. >>>> >>>> WDYT? >>>> >>>> Thanks, >>>> Anca

Hi devs, to resume, and try to converge to an implementable version, I propose: 1/ adding only OBJECT and PROPERTY EntityTypes for the moment, referring to an object instance and a property instance in a document (a property ref would have an object as a parent which would have a document reference as a parent), and limiting the implementation to references to properties of object instances (leaving aside type definitions ftm). here's my +1 for this.

2/ using a serialization of the form wiki:Space.Page^className[objectnumber]#property and

a) using indexed ('multivalued') references, adding an additional IndexedEntityReference class, to which API caller would have to cast. ObjectReference would be such an IndexedEntityReference and provide object related helper functions. b) className[objectnumber] is used as an 'object name', it would be the name of the object reference, and it would be the caller of the generic API that would have to parse& serialize this kind of strings to actually extract classname and object index. However, this would again be all hidden behind the ObjectReference API. I'm 0.5 and 0.5 between the two, any would suit my purpose.

An additional question is what would wiki:Space.Page^className (and wiki:Space.Page^className#property) mean: i) nothing, we consider it as invalid reference, we'll fix that later, we keep it simple ftm my +1 goes for this ii) all objects of class className in the document iii) first object of that class in the document (as XWikiDocument#getObject(className) does) iv) a shortcut for wiki:Space.Page^className[0] (which, note, does not necessarily mean the first object in that document, since indexing of objs in a document is not recomputed when objects are deleted).

On 01/13/2010 02:42 PM, Anca Luca wrote: > Hi devs, > > Short story: > 1/ add the CLASS, OBJECT, PROPERTY EntityTypes in the model > > +1 > > 2/ serialization for referencing a property of an object > a) wiki:Space.Page^className[objectNumber]#property > b) wiki:Space.Page^className#objectNumber$property > +0.75 for b) > > Long story: > > 1/ I would need to extend the EntityReference to be able to target a > property in an object in a document. > For this, I will need to add > > /** > * Represents a Class Entity > */ > CLASS, > > /** > * Represents an Object Entity. > */ > OBJECT, > > /** > * Represents a Property Entity > */ > PROPERTY, > > in the EntityType. Although I would prefer an extensible framework that > would allow to extend the possible entity types without changing an enum > in the platform (for any API user to be able to define its own > references), I think this is fairly extensible (these are key concepts > in the xwiki model and I don't think they would be changed that soon, > and their interpretation is flexible, they could be combined with any > parent to generate either references to class definitions or instances). > here's my +1 for this. > > 2/ I would also need a 'standard' string serialization for these. Now, > there's also the option to do it in my own module (annotations) because > only I need it ftm, but I prefer to have a platform wide approach. Opinions? > There are 2 choices, with a potentially different combination of separators: > > a/ wiki:Space.Page^className[objectNumber]#property > > pros: it's a suggestive way to access objects by number ([] is the > standard syntax for array indexed access and the objects are accessed by > index), [] is supported by JCR so maybe we should support it too > cons: [] is somewhat inconsistent with all other separators which are > just one separator, to the left (right) of the entity, harder to > implement the [] separators on the current framework > > b/ wiki:Space.Page^className#objectNumber$property > > pros: inline with the separator usage we already have (and easier to > implement for this reason), could be easier refactored to contain an > object name instead of the number > cons: $ separator can collide with velocity syntax (can potentially > cause trouble when used in velocity -- an alternative could be the pipe > |), could be harder to drop the object number part of the reference to > refer a property in a class (if wanted, in the future) > > I have no other argument between a) and b) but the implementation speed > one, so I'd go for a b)-like approach, in the spirit of the current > separators.

Hi devs, to resume, and try to converge to an implementable version, I propose: 1/ adding only OBJECT and PROPERTY EntityTypes for the moment, referring to an object instance and a property instance in a document (a property ref would have an object as a parent which would have a document reference as a parent), and limiting the implementation to references to properties of object instances (leaving aside type definitions ftm). here's my +1 for this.

2/ using a serialization of the form wiki:Space.Page^className[objectnumber]#property and

a) using indexed ('multivalued') references, adding an additional IndexedEntityReference class, to which API caller would have to cast. ObjectReference would be such an IndexedEntityReference and provide object related helper functions. b) className[objectnumber] is used as an 'object name', it would be the name of the object reference, and it would be the caller of the generic API that would have to parse & serialize this kind of strings to actually extract classname and object index. However, this would again be all hidden behind the ObjectReference API. I'm 0.5 and 0.5 between the two, any would suit my purpose. An additional question is what would wiki:Space.Page^className (and wiki:Space.Page^className#property) mean: i) nothing, we consider it as invalid reference, we'll fix that later, we keep it simple ftm my +1 goes for this

ii) all objects of class className in the document

iii) first object of that class in the document (as XWikiDocument#getObject(className) does)

iv) a shortcut for wiki:Space.Page^className[0] (which, note, does not necessarily mean the first object in that document, since indexing of objs in a document is not recomputed when objects are deleted).

WDYT? Thanks, Anca On 01/13/2010 02:42 PM, Anca Luca wrote: _______________________________________________ devs mailing list devs(a)xwiki.org http://lists.xwiki.org/mailman/listinfo/devs

Hi Thomas, On 01/19/2010 12:29 PM, Thomas Mortagne wrote: but anything could potentially point to nothing, the class could not exist, or the object or the property name (or a document could not exist), it's more about the semantic that we associate with such a reference. The 0 value came rather from the potential generic approach that an indexed reference which would have no specified index could be considered as having the index 0.

However, I think it should be the 'first' object, since it is a much more used reference, and also it's the way the API works (if you ask a prop to be displayed for a doc, for example, the first object of that class will be used), so users are accustomed to it.

Thanks, Anca _______________________________________________ devs mailing list devs(a)xwiki.org http://lists.xwiki.org/mailman/listinfo/devs

Hi devs, here's a resume of the approach, as it has been voted so far: 1/ add OBJECT and PROPERTY Entity Types 3 +1, 1 -1: Vincent can you lift your veto from this one, if approach suits you?

2/ using a serialization of the form wiki:Space.Page^className[objectnumber]#property 2 +1 (or 1 +1, 1 +0.5 if we take into account separators votes) a) implementing with indexed references ('multivalued'): 1 +0.5 , 1 +0, b) implementing with object names computed as className[number] 1 +0.5, 1 +1, 1 -1: Vincent, Sergiu, could you reach some sort of an agreement on this?

3/ how to interpret wiki:Space.Page^className (wiki:Space.Page^className#property) i) consider invalid 1 -0, 1 +1 we can consider always valid with the meaning described at http://n2.nabble.com/proposal-discussion-Object-properties-references-tp434… and the approach voted (iii so far, it seems) ii) as a list of all objects not consistent with references model so far iii) first object 1 +0, 1 +0.75, 1 +1 iv) object with index 0 1 +0 Unless there are -1s, I would like to start implementing: 1/, 2/, a), iii)

Thanks, Anca On 01/18/2010 04:54 PM, Anca Luca wrote: > Hi devs, > > to resume, and try to converge to an implementable version, I propose: > > 1/ adding only OBJECT and PROPERTY EntityTypes for the moment, referring to an > object instance and a property instance in a document (a property ref would have > an object as a parent which would have a document reference as a parent), and > limiting the implementation to references to properties of object instances > (leaving aside type definitions ftm). > > here's my +1 for this. > > 2/ using a serialization of the form > wiki:Space.Page^className[objectnumber]#property and > > a) using indexed ('multivalued') references, adding an additional > IndexedEntityReference class, to which API caller would have to cast. > ObjectReference would be such an IndexedEntityReference and provide object > related helper functions. > > b) className[objectnumber] is used as an 'object name', it would be the name of > the object reference, and it would be the caller of the generic API that would > have to parse& serialize this kind of strings to actually extract classname and > object index. However, this would again be all hidden behind the ObjectReference > API. > > I'm 0.5 and 0.5 between the two, any would suit my purpose. > > An additional question is what would wiki:Space.Page^className (and > wiki:Space.Page^className#property) mean: > i) nothing, we consider it as invalid reference, we'll fix that later, we keep > it simple ftm > > my +1 goes for this > > ii) all objects of class className in the document > > iii) first object of that class in the document (as > XWikiDocument#getObject(className) does) > > iv) a shortcut for wiki:Space.Page^className[0] (which, note, does not > necessarily mean the first object in that document, since indexing of objs in a > document is not recomputed when objects are deleted). > > WDYT? > > Thanks, > Anca > > On 01/13/2010 02:42 PM, Anca Luca wrote: >> Hi devs, >> >> Short story: >> 1/ add the CLASS, OBJECT, PROPERTY EntityTypes in the model >> >> +1 >> >> 2/ serialization for referencing a property of an object >> a) wiki:Space.Page^className[objectNumber]#property >> b) wiki:Space.Page^className#objectNumber$property >> +0.75 for b) >> >> Long story: >> >> 1/ I would need to extend the EntityReference to be able to target a >> property in an object in a document. >> For this, I will need to add >> >> /** >> * Represents a Class Entity >> */ >> CLASS, >> >> /** >> * Represents an Object Entity. >> */ >> OBJECT, >> >> /** >> * Represents a Property Entity >> */ >> PROPERTY, >> >> in the EntityType. Although I would prefer an extensible framework that >> would allow to extend the possible entity types without changing an enum >> in the platform (for any API user to be able to define its own >> references), I think this is fairly extensible (these are key concepts >> in the xwiki model and I don't think they would be changed that soon, >> and their interpretation is flexible, they could be combined with any >> parent to generate either references to class definitions or instances). >> here's my +1 for this. >> >> 2/ I would also need a 'standard' string serialization for these. Now, >> there's also the option to do it in my own module (annotations) because >> only I need it ftm, but I prefer to have a platform wide approach. Opinions? >> There are 2 choices, with a potentially different combination of separators: >> >> a/ wiki:Space.Page^className[objectNumber]#property >> >> pros: it's a suggestive way to access objects by number ([] is the >> standard syntax for array indexed access and the objects are accessed by >> index), [] is supported by JCR so maybe we should support it too >> cons: [] is somewhat inconsistent with all other separators which are >> just one separator, to the left (right) of the entity, harder to >> implement the [] separators on the current framework >> >> b/ wiki:Space.Page^className#objectNumber$property >> >> pros: inline with the separator usage we already have (and easier to >> implement for this reason), could be easier refactored to contain an >> object name instead of the number >> cons: $ separator can collide with velocity syntax (can potentially >> cause trouble when used in velocity -- an alternative could be the pipe >> |), could be harder to drop the object number part of the reference to >> refer a property in a class (if wanted, in the future) >> >> I have no other argument between a) and b) but the implementation speed >> one, so I'd go for a b)-like approach, in the spirit of the current >> separators. >> >> WDYT? >> >> Thanks, >> Anca

Hi Vincent, On 01/19/2010 03:12 PM, Vincent Massol wrote: The constant names you mean? If so, I propose OBJECT and PROPERTY, as mentioned above, which also seem to be 'inline' with the new model on the sandbox (although there is no property instance there). And when we'll need the other ones, which is not the case now, we can use OBJECT_DEFINITION and OBJECT_DEFINITION_PROPERTY. here's my +1,

WDYT? > >> 2/ using a serialization of the form >> wiki:Space.Page^className[objectnumber]#property >> 2 +1 (or 1 +1, 1 +0.5 if we take into account separators votes) >> a) implementing with indexed references ('multivalued'): >> 1 +0.5 , 1 +0, >> b) implementing with object names computed as className[number] >> 1 +0.5, 1 +1, 1 -1: Vincent, Sergiu, could you reach some sort of an agreement >> on this? > > I'd like to see Thomas' opinion too. I couldn't find it in his replies. > >> 3/ how to interpret wiki:Space.Page^className (wiki:Space.Page^className#property) >> >> i) consider invalid >> 1 -0, 1 +1 >> we can consider always valid with the meaning described at >> http://n2.nabble.com/proposal-discussion-Object-properties-references-tp434… >> and the approach voted (iii so far, it seems) >> >> ii) as a list of all objects >> not consistent with references model so far >> >> iii) first object >> 1 +0, 1 +0.75, 1 +1 >> >> iv) object with index 0 >> 1 +0 >> >> Unless there are -1s, I would like to start implementing: >> 1/, 2/, a), iii) > > I'm fine with 1/, 2/, A), iii) except for 1/ for which we need to agree on names before you can commit it. > > Thanks > -Vincent > >> >> Thanks, >> Anca >> >> >> On 01/18/2010 04:54 PM, Anca Luca wrote: >>> Hi devs, >>> >>> to resume, and try to converge to an implementable version, I propose: >>> >>> 1/ adding only OBJECT and PROPERTY EntityTypes for the moment, referring to an >>> object instance and a property instance in a document (a property ref would have >>> an object as a parent which would have a document reference as a parent), and >>> limiting the implementation to references to properties of object instances >>> (leaving aside type definitions ftm). >>> >>> here's my +1 for this. >>> >>> 2/ using a serialization of the form >>> wiki:Space.Page^className[objectnumber]#property and >>> >>> a) using indexed ('multivalued') references, adding an additional >>> IndexedEntityReference class, to which API caller would have to cast. >>> ObjectReference would be such an IndexedEntityReference and provide object >>> related helper functions. >>> >>> b) className[objectnumber] is used as an 'object name', it would be the name of >>> the object reference, and it would be the caller of the generic API that would >>> have to parse& serialize this kind of strings to actually extract classname and >>> object index. However, this would again be all hidden behind the ObjectReference >>> API. >>> >>> I'm 0.5 and 0.5 between the two, any would suit my purpose. >>> >>> An additional question is what would wiki:Space.Page^className (and >>> wiki:Space.Page^className#property) mean: >>> i) nothing, we consider it as invalid reference, we'll fix that later, we keep >>> it simple ftm >>> >>> my +1 goes for this >>> >>> ii) all objects of class className in the document >>> >>> iii) first object of that class in the document (as >>> XWikiDocument#getObject(className) does) >>> >>> iv) a shortcut for wiki:Space.Page^className[0] (which, note, does not >>> necessarily mean the first object in that document, since indexing of objs in a >>> document is not recomputed when objects are deleted). >>> >>> WDYT? >>> >>> Thanks, >>> Anca >>> >>> On 01/13/2010 02:42 PM, Anca Luca wrote: >>>> Hi devs, >>>> >>>> Short story: >>>> 1/ add the CLASS, OBJECT, PROPERTY EntityTypes in the model >>>> >>>> +1 >>>> >>>> 2/ serialization for referencing a property of an object >>>> a) wiki:Space.Page^className[objectNumber]#property >>>> b) wiki:Space.Page^className#objectNumber$property >>>> +0.75 for b) >>>> >>>> Long story: >>>> >>>> 1/ I would need to extend the EntityReference to be able to target a >>>> property in an object in a document. >>>> For this, I will need to add >>>> >>>> /** >>>> * Represents a Class Entity >>>> */ >>>> CLASS, >>>> >>>> /** >>>> * Represents an Object Entity. >>>> */ >>>> OBJECT, >>>> >>>> /** >>>> * Represents a Property Entity >>>> */ >>>> PROPERTY, >>>> >>>> in the EntityType. Although I would prefer an extensible framework that >>>> would allow to extend the possible entity types without changing an enum >>>> in the platform (for any API user to be able to define its own >>>> references), I think this is fairly extensible (these are key concepts >>>> in the xwiki model and I don't think they would be changed that soon, >>>> and their interpretation is flexible, they could be combined with any >>>> parent to generate either references to class definitions or instances). >>>> here's my +1 for this. >>>> >>>> 2/ I would also need a 'standard' string serialization for these. Now, >>>> there's also the option to do it in my own module (annotations) because >>>> only I need it ftm, but I prefer to have a platform wide approach. Opinions? >>>> There are 2 choices, with a potentially different combination of separators: >>>> >>>> a/ wiki:Space.Page^className[objectNumber]#property >>>> >>>> pros: it's a suggestive way to access objects by number ([] is the >>>> standard syntax for array indexed access and the objects are accessed by >>>> index), [] is supported by JCR so maybe we should support it too >>>> cons: [] is somewhat inconsistent with all other separators which are >>>> just one separator, to the left (right) of the entity, harder to >>>> implement the [] separators on the current framework >>>> >>>> b/ wiki:Space.Page^className#objectNumber$property >>>> >>>> pros: inline with the separator usage we already have (and easier to >>>> implement for this reason), could be easier refactored to contain an >>>> object name instead of the number >>>> cons: $ separator can collide with velocity syntax (can potentially >>>> cause trouble when used in velocity -- an alternative could be the pipe >>>> |), could be harder to drop the object number part of the reference to >>>> refer a property in a class (if wanted, in the future) >>>> >>>> I have no other argument between a) and b) but the implementation speed >>>> one, so I'd go for a b)-like approach, in the spirit of the current >>>> separators. >>>> >>>> WDYT? >>>> >>>> Thanks, >>>> Anca

On Jan 19, 2010, at 4:29 PM, Anca Luca wrote: I'm not sure yet about the names. They may need to be refactored later on. Here's what I propose: * OBJECT * OBJECT_PROPERTY (rather than PROPERTY which looks too ambiguous since we have at least 3 notions of properties)

Thanks -Vincent _______________________________________________ devs mailing list devs(a)xwiki.org http://lists.xwiki.org/mailman/listinfo/devs

Hi devs, On 01/19/2010 03:01 PM, Anca Luca wrote: Actually # is causing problems in velocity too, because it's the macro invocation char. For example, this {{velocity}} #macro(property) this is a test macro #end #set($var1 = "wiki:Space.Page^object#property") $var1 {{/velocity}} displays: wiki:Space.Page^objectthis is a test macro Of course, 6th line can be changed to #set($var1 = "wiki:Space.Page^object\#property") and it will work as expected but the I'd really prefer to avoid escaping, since it's known to be problematic. Also, Sergiu suggested at some point using the &s, I prefer to avoid that too for as long as possible since it can cause problems with URLs. Some proposals would be ^ for object names and pipe or semicolon for properties: wiki:Space.Page^objectName|prop wiki:Space.Page^objectName;prop or, for property separator, we could also think of ! ~ > or ^ again.

In terms of escaping, it means that every time the property separator actually appears in the property name, it has to be escaped and every time the object separator appears in the object name itself, it has to be escaped. Knowing this, I'd prefer to keep the ^ as the objectname separator since it's quite an unusual char and chances for it to appear in an object name (which we could think of as "as complex as a document name") are small. For property names though, I really wouldn't expect any non alphadigit character (other than _) to ever appear. Thanks, Anca _______________________________________________ devs mailing list devs(a)xwiki.org http://lists.xwiki.org/mailman/listinfo/devs

Hi devs, On 01/19/2010 03:01 PM, Anca Luca wrote: Actually # is causing problems in velocity too, because it's the macro invocation char. For example, this {{velocity}} #macro(property) this is a test macro #end #set($var1 = "wiki:Space.Page^object#property") $var1 {{/velocity}} displays: wiki:Space.Page^objectthis is a test macro Of course, 6th line can be changed to #set($var1 = "wiki:Space.Page^object\#property") and it will work as expected but the I'd really prefer to avoid escaping, since it's known to be problematic.

Also, Sergiu suggested at some point using the &s, I prefer to avoid that too for as long as possible since it can cause problems with URLs.

Some proposals would be ^ for object names and pipe or semicolon for properties:

wiki:Space.Page^objectName|prop wiki:Space.Page^objectName;prop

or, for property separator, we could also think of ! ~ > or ^ again. In terms of escaping, it means that every time the property separator actually appears in the property name, it has to be escaped and every time the object separator appears in the object name itself, it has to be escaped.

Knowing this, I'd prefer to keep the ^ as the objectname separator since it's quite an unusual char and chances for it to appear in an object name (which we could think of as "as complex as a document name") are small. For property names though, I really wouldn't expect any non alphadigit character (other than _) to ever appear.

Thanks, Anca > a) implementing with indexed references ('multivalued'): > 1 +0.5 , 1 +0, > b) implementing with object names computed as className[number] > 1 +0.5, 1 +1, 1 -1: Vincent, Sergiu, could you reach some sort of an agreement > on this? > > 3/ how to interpret wiki:Space.Page^className (wiki:Space.Page^className#property) > > i) consider invalid > 1 -0, 1 +1 > we can consider always valid with the meaning described at > http://n2.nabble.com/proposal-discussion-Object-properties-references-tp434… > and the approach voted (iii so far, it seems) > > ii) as a list of all objects > not consistent with references model so far > > iii) first object > 1 +0, 1 +0.75, 1 +1 > > iv) object with index 0 > 1 +0 > > Unless there are -1s, I would like to start implementing: > 1/, 2/, a), iii) > > Thanks, > Anca > > > On 01/18/2010 04:54 PM, Anca Luca wrote: >> Hi devs, >> >> to resume, and try to converge to an implementable version, I propose: >> >> 1/ adding only OBJECT and PROPERTY EntityTypes for the moment, referring to an >> object instance and a property instance in a document (a property ref would have >> an object as a parent which would have a document reference as a parent), and >> limiting the implementation to references to properties of object instances >> (leaving aside type definitions ftm). >> >> here's my +1 for this. >> >> 2/ using a serialization of the form >> wiki:Space.Page^className[objectnumber]#property and >> >> a) using indexed ('multivalued') references, adding an additional >> IndexedEntityReference class, to which API caller would have to cast. >> ObjectReference would be such an IndexedEntityReference and provide object >> related helper functions. >> >> b) className[objectnumber] is used as an 'object name', it would be the name of >> the object reference, and it would be the caller of the generic API that would >> have to parse& serialize this kind of strings to actually extract classname and >> object index. However, this would again be all hidden behind the ObjectReference >> API. >> >> I'm 0.5 and 0.5 between the two, any would suit my purpose. >> >> An additional question is what would wiki:Space.Page^className (and >> wiki:Space.Page^className#property) mean: >> i) nothing, we consider it as invalid reference, we'll fix that later, we keep >> it simple ftm >> >> my +1 goes for this >> >> ii) all objects of class className in the document >> >> iii) first object of that class in the document (as >> XWikiDocument#getObject(className) does) >> >> iv) a shortcut for wiki:Space.Page^className[0] (which, note, does not >> necessarily mean the first object in that document, since indexing of objs in a >> document is not recomputed when objects are deleted). >> >> WDYT? >> >> Thanks, >> Anca >> >> On 01/13/2010 02:42 PM, Anca Luca wrote: >>> Hi devs, >>> >>> Short story: >>> 1/ add the CLASS, OBJECT, PROPERTY EntityTypes in the model >>> >>> +1 >>> >>> 2/ serialization for referencing a property of an object >>> a) wiki:Space.Page^className[objectNumber]#property >>> b) wiki:Space.Page^className#objectNumber$property >>> +0.75 for b) >>> >>> Long story: >>> >>> 1/ I would need to extend the EntityReference to be able to target a >>> property in an object in a document. >>> For this, I will need to add >>> >>> /** >>> * Represents a Class Entity >>> */ >>> CLASS, >>> >>> /** >>> * Represents an Object Entity. >>> */ >>> OBJECT, >>> >>> /** >>> * Represents a Property Entity >>> */ >>> PROPERTY, >>> >>> in the EntityType. Although I would prefer an extensible framework that >>> would allow to extend the possible entity types without changing an enum >>> in the platform (for any API user to be able to define its own >>> references), I think this is fairly extensible (these are key concepts >>> in the xwiki model and I don't think they would be changed that soon, >>> and their interpretation is flexible, they could be combined with any >>> parent to generate either references to class definitions or instances). >>> here's my +1 for this. >>> >>> 2/ I would also need a 'standard' string serialization for these. Now, >>> there's also the option to do it in my own module (annotations) because >>> only I need it ftm, but I prefer to have a platform wide approach. Opinions? >>> There are 2 choices, with a potentially different combination of separators: >>> >>> a/ wiki:Space.Page^className[objectNumber]#property >>> >>> pros: it's a suggestive way to access objects by number ([] is the >>> standard syntax for array indexed access and the objects are accessed by >>> index), [] is supported by JCR so maybe we should support it too >>> cons: [] is somewhat inconsistent with all other separators which are >>> just one separator, to the left (right) of the entity, harder to >>> implement the [] separators on the current framework >>> >>> b/ wiki:Space.Page^className#objectNumber$property >>> >>> pros: inline with the separator usage we already have (and easier to >>> implement for this reason), could be easier refactored to contain an >>> object name instead of the number >>> cons: $ separator can collide with velocity syntax (can potentially >>> cause trouble when used in velocity -- an alternative could be the pipe >>> |), could be harder to drop the object number part of the reference to >>> refer a property in a class (if wanted, in the future) >>> >>> I have no other argument between a) and b) but the implementation speed >>> one, so I'd go for a b)-like approach, in the spirit of the current >>> separators. >>> >>> WDYT? >>> >>> Thanks, >>> Anca

Hi Vincent, On 01/21/2010 11:52 AM, Vincent Massol wrote: I disagree here. I think that's why we're bothering to create these refs, to be used in scripts (in their serialized form). I would use them in scripts in annotations. Also, the devs will have to escape that hash _every single time_ since macros can be defined by other sources than themselves and available in the context they're running their script in (e.g. macros.vm) and collide with the property name and cause unexpected results. I prefer to avoid this case if possible, because devs will forget to do that, otherwise put, less bugs than more, if i have the choice.  From my memories of scripting in XWiki, escaping in velocity can be an issue. Think about having more sophisticated constructions with strings that contain calls of object functions with strings as parameters, normally that works but when it comes to escaping there can be pbs. Or this might have been a problem only in syntax 1.0 since there were 4 syntaxes on top of eachother, I don't know, but I prefer to avoid it, if possible. it _can_ be url encoded, but nothing guarantees that people wouldn't forget to do it. otherwise put, less bugs than more if I have the choice. They can now too, I think, just the same way the object name can have a ^. My expectation is only a general feeling about how I know programmers name their field names. It's a question of small probability, not impossibility. Even if we expose types creation to 'regular non-devs' users (with a wizard or something), I still think property names would stay a lot simpler than document names, for example (I don't see anyone adding a full sentence as a property name, with punctuation, and whatever chars, while I see them naming a document with a sentence). Thanks, Anca _______________________________________________ devs mailing list devs(a)xwiki.org http://lists.xwiki.org/mailman/listinfo/devs

Hi Flavius, On 01/21/2010 02:53 PM, Flavius Olaru wrote: no, there shouldn't be any problem in implementing this. depending on where you're looking from, same separator for different entities can be a bit confusing too (since when you see . you think about space page separator only to later realize, ah there's another dot which is actually the separator, etc. Also think that these serialized forms could be relative, e.g. not contain the document part but only the object.property part. While the code won't have any issue with it, the user reading it might...) Also the model of interpreting objects in pages as spaces in a wiki and properties in obj as pages in a space, and using the same separator could be a bit confusing since it's not really the same thing (though the parallel is somewhat legitimate) and we're just mixing them up in the user's head. It depends on how you look at things. . is indeed a very good (read "intuitive") separator between objects and properties. However, like this, the object would have to escape its :s. there would be a tiny issue with one of the currently possible implementations of the name (which is the classname[objectnumber], since if one wants class name absolute it would have to use a : which would need to be escaped and the ref would be less visible), but that shouldn't stop the approach for the new model. All in all, I think it's a good idea, as I said I like the dot intuitive separator.

+0 Anca > > Thanks, > Flavius > > On Thu, Jan 21, 2010 at 12:14 PM, Anca Luca<ancapaula.luca(a)xwiki.com> wrote: >> Hi Vincent, >> >> On 01/21/2010 11:52 AM, Vincent Massol wrote: >>> >>> On Jan 21, 2010, at 10:34 AM, Anca Luca wrote: >>> >>>> Hi devs, >>>> >>>> On 01/19/2010 03:01 PM, Anca Luca wrote: >>>>> Hi devs, >>>>> >>>>> here's a resume of the approach, as it has been voted so far: >>>>> 1/ add OBJECT and PROPERTY Entity Types >>>>> >>>>> 3 +1, 1 -1: Vincent can you lift your veto from this one, if approach suits you? >>>>> >>>>> 2/ using a serialization of the form >>>>> wiki:Space.Page^className[objectnumber]#property >>>>> 2 +1 (or 1 +1, 1 +0.5 if we take into account separators votes) >>>> >>>> Actually # is causing problems in velocity too, because it's the macro >>>> invocation char. For example, this >>>> >>>> {{velocity}} >>>> #macro(property) >>>> this is a test macro >>>> #end >>>> >>>> #set($var1 = "wiki:Space.Page^object#property") >>>> >>>> $var1 >>>> {{/velocity}} >>>> >>>> displays: >>>> >>>> wiki:Space.Page^objectthis is a test macro >>>> >>>> Of course, 6th line can be changed to >>>> #set($var1 = "wiki:Space.Page^object\#property") >>>> and it will work as expected but the I'd really prefer to avoid escaping, since >>>> it's known to be problematic. >>> >>> I'm not sure it's a problem. I can't find many examples where we would use object references in velocity scripts and when we do there's a solution (the escape as you mentioned). >> >> I disagree here. I think that's why we're bothering to create these refs, to be >> used in scripts (in their serialized form). I would use them in scripts in >> annotations. >> Also, the devs will have to escape that hash _every single time_ since macros >> can be defined by other sources than themselves and available in the context >> they're running their script in (e.g. macros.vm) and collide with the property >> name and cause unexpected results. I prefer to avoid this case if possible, >> because devs will forget to do that, otherwise put, less bugs than more, if i >> have the choice. >> From my memories of scripting in XWiki, escaping in velocity can be an issue. >> Think about having more sophisticated constructions with strings that contain >> calls of object functions with strings as parameters, normally that works but >> when it comes to escaping there can be pbs. Or this might have been a problem >> only in syntax 1.0 since there were 4 syntaxes on top of eachother, I don't >> know, but I prefer to avoid it, if possible. >> >>> >>>> Also, Sergiu suggested at some point using the&s, I prefer to avoid that too >>>> for as long as possible since it can cause problems with URLs. >>> >>> I don't think it would since the character would be URL-encoded. >> >> it _can_ be url encoded, but nothing guarantees that people wouldn't forget to >> do it. otherwise put, less bugs than more if I have the choice. >> >>> >>>> Some proposals would be ^ for object names and pipe or semicolon for properties: >>> >>> Pipe is hard on some keyboards but it shouldn' t be a showstopper. >>> >>>> wiki:Space.Page^objectName|prop >>>> wiki:Space.Page^objectName;prop >>> >>> These separators don't feel natural to me. I think I still prefer the hash. >>> >>>> or, for property separator, we could also think of ! ~> or ^ again. >>>> >>>> In terms of escaping, it means that every time the property separator actually >>>> appears in the property name, it has to be escaped and every time the object >>>> separator appears in the object name itself, it has to be escaped. >>> >>> Yep. >>> >>>> Knowing this, I'd prefer to keep the ^ as the objectname separator since it's >>>> quite an unusual char and chances for it to appear in an object name (which we >>>> could think of as "as complex as a document name") are small. For property names >>>> though, I really wouldn't expect any non alphadigit character (other than _) to >>>> ever appear. >>> >>> Property names could have any character in the future. >> >> They can now too, I think, just the same way the object name can have a ^. My >> expectation is only a general feeling about how I know programmers name their >> field names. It's a question of small probability, not impossibility. >> >> Even if we expose types creation to 'regular non-devs' users (with a wizard or >> something), I still think property names would stay a lot simpler than document >> names, for example (I don't see anyone adding a full sentence as a property >> name, with punctuation, and whatever chars, while I see them naming a document >> with a sentence). >> >> Thanks, >> Anca >> >>> >>> Thanks >>> -Vincent >>> >>>> >>>> Thanks, >>>> Anca >>>> >>>> >>>>> a) implementing with indexed references ('multivalued'): >>>>> 1 +0.5 , 1 +0, >>>>> b) implementing with object names computed as className[number] >>>>> 1 +0.5, 1 +1, 1 -1: Vincent, Sergiu, could you reach some sort of an agreement >>>>> on this? >>>>> >>>>> 3/ how to interpret wiki:Space.Page^className (wiki:Space.Page^className#property) >>>>> >>>>> i) consider invalid >>>>> 1 -0, 1 +1 >>>>> we can consider always valid with the meaning described at >>>>> http://n2.nabble.com/proposal-discussion-Object-properties-references-tp434… >>>>> and the approach voted (iii so far, it seems) >>>>> >>>>> ii) as a list of all objects >>>>> not consistent with references model so far >>>>> >>>>> iii) first object >>>>> 1 +0, 1 +0.75, 1 +1 >>>>> >>>>> iv) object with index 0 >>>>> 1 +0 >>>>> >>>>> Unless there are -1s, I would like to start implementing: >>>>> 1/, 2/, a), iii) >>>>> >>>>> Thanks, >>>>> Anca >>>>> >>>>> >>>>> On 01/18/2010 04:54 PM, Anca Luca wrote: >>>>>> Hi devs, >>>>>> >>>>>> to resume, and try to converge to an implementable version, I propose: >>>>>> >>>>>> 1/ adding only OBJECT and PROPERTY EntityTypes for the moment, referring to an >>>>>> object instance and a property instance in a document (a property ref would have >>>>>> an object as a parent which would have a document reference as a parent), and >>>>>> limiting the implementation to references to properties of object instances >>>>>> (leaving aside type definitions ftm). >>>>>> >>>>>> here's my +1 for this. >>>>>> >>>>>> 2/ using a serialization of the form >>>>>> wiki:Space.Page^className[objectnumber]#property and >>>>>> >>>>>> a) using indexed ('multivalued') references, adding an additional >>>>>> IndexedEntityReference class, to which API caller would have to cast. >>>>>> ObjectReference would be such an IndexedEntityReference and provide object >>>>>> related helper functions. >>>>>> >>>>>> b) className[objectnumber] is used as an 'object name', it would be the name of >>>>>> the object reference, and it would be the caller of the generic API that would >>>>>> have to parse& serialize this kind of strings to actually extract classname and >>>>>> object index. However, this would again be all hidden behind the ObjectReference >>>>>> API. >>>>>> >>>>>> I'm 0.5 and 0.5 between the two, any would suit my purpose. >>>>>> >>>>>> An additional question is what would wiki:Space.Page^className (and >>>>>> wiki:Space.Page^className#property) mean: >>>>>> i) nothing, we consider it as invalid reference, we'll fix that later, we keep >>>>>> it simple ftm >>>>>> >>>>>> my +1 goes for this >>>>>> >>>>>> ii) all objects of class className in the document >>>>>> >>>>>> iii) first object of that class in the document (as >>>>>> XWikiDocument#getObject(className) does) >>>>>> >>>>>> iv) a shortcut for wiki:Space.Page^className[0] (which, note, does not >>>>>> necessarily mean the first object in that document, since indexing of objs in a >>>>>> document is not recomputed when objects are deleted). >>>>>> >>>>>> WDYT? >>>>>> >>>>>> Thanks, >>>>>> Anca >>>>>> >>>>>> On 01/13/2010 02:42 PM, Anca Luca wrote: >>>>>>> Hi devs, >>>>>>> >>>>>>> Short story: >>>>>>> 1/ add the CLASS, OBJECT, PROPERTY EntityTypes in the model >>>>>>> >>>>>>> +1 >>>>>>> >>>>>>> 2/ serialization for referencing a property of an object >>>>>>> a) wiki:Space.Page^className[objectNumber]#property >>>>>>> b) wiki:Space.Page^className#objectNumber$property >>>>>>> +0.75 for b) >>>>>>> >>>>>>> Long story: >>>>>>> >>>>>>> 1/ I would need to extend the EntityReference to be able to target a >>>>>>> property in an object in a document. >>>>>>> For this, I will need to add >>>>>>> >>>>>>> /** >>>>>>> * Represents a Class Entity >>>>>>> */ >>>>>>> CLASS, >>>>>>> >>>>>>> /** >>>>>>> * Represents an Object Entity. >>>>>>> */ >>>>>>> OBJECT, >>>>>>> >>>>>>> /** >>>>>>> * Represents a Property Entity >>>>>>> */ >>>>>>> PROPERTY, >>>>>>> >>>>>>> in the EntityType. Although I would prefer an extensible framework that >>>>>>> would allow to extend the possible entity types without changing an enum >>>>>>> in the platform (for any API user to be able to define its own >>>>>>> references), I think this is fairly extensible (these are key concepts >>>>>>> in the xwiki model and I don't think they would be changed that soon, >>>>>>> and their interpretation is flexible, they could be combined with any >>>>>>> parent to generate either references to class definitions or instances). >>>>>>> here's my +1 for this. >>>>>>> >>>>>>> 2/ I would also need a 'standard' string serialization for these. Now, >>>>>>> there's also the option to do it in my own module (annotations) because >>>>>>> only I need it ftm, but I prefer to have a platform wide approach. Opinions? >>>>>>> There are 2 choices, with a potentially different combination of separators: >>>>>>> >>>>>>> a/ wiki:Space.Page^className[objectNumber]#property >>>>>>> >>>>>>> pros: it's a suggestive way to access objects by number ([] is the >>>>>>> standard syntax for array indexed access and the objects are accessed by >>>>>>> index), [] is supported by JCR so maybe we should support it too >>>>>>> cons: [] is somewhat inconsistent with all other separators which are >>>>>>> just one separator, to the left (right) of the entity, harder to >>>>>>> implement the [] separators on the current framework >>>>>>> >>>>>>> b/ wiki:Space.Page^className#objectNumber$property >>>>>>> >>>>>>> pros: inline with the separator usage we already have (and easier to >>>>>>> implement for this reason), could be easier refactored to contain an >>>>>>> object name instead of the number >>>>>>> cons: $ separator can collide with velocity syntax (can potentially >>>>>>> cause trouble when used in velocity -- an alternative could be the pipe >>>>>>> |), could be harder to drop the object number part of the reference to >>>>>>> refer a property in a class (if wanted, in the future) >>>>>>> >>>>>>> I have no other argument between a) and b) but the implementation speed >>>>>>> one, so I'd go for a b)-like approach, in the spirit of the current >>>>>>> separators. >>>>>>> >>>>>>> WDYT? >>>>>>> >>>>>>> Thanks, >>>>>>> Anca

After discussing with Thomas we've reached the following conclusion: * We need to decide if we agree that in the future we want Objects to have a free name (ie any name - when an object is added to a document a computed name could be proposed but the user would be able to choose any name he wants). Our POV is that all Entities in XWiki should have a free name. * If this is agreed then the best solution for now it to consider "classname[number]" as an object name in EntityReference and to have temporary getters in ObjectReference to get the classname and the number (names for the getters to be decided: getIndex, getNumber, getPosition, etc). Of course getName() would perform the serialization. These 2 getters would be temporary and deprecated later on when the model accepts free form object names.

This means that if we agree all Entities have a free name then there's no need to have "multivalue"/"indexed" reference names.

Thanks -Vincent On Jan 18, 2010, at 3:54 PM, Anca Luca wrote: _______________________________________________ devs mailing list devs(a)xwiki.org http://lists.xwiki.org/mailman/listinfo/devs

Hi Vincent, On 01/19/2010 05:11 PM, Vincent Massol wrote: Yes, it's the same question as I was asking, but put otherwise, in a more future envisaging manner (I think we discussed about it like this at least 2 times on the development chat). However, if we implement it with a multivalued / indexed ref name now, with "temporary getters in ObjectReference to get the classname and the number" and then, when we decide if we agree on having free names we just switch that to a regular, non-indexed reference, what's the difference?

Otherwise put, does the implementation at this point actually depend on this decision?

Thanks, Anca _______________________________________________ devs mailing list devs(a)xwiki.org http://lists.xwiki.org/mailman/listinfo/devs