about propertyAt: and others
Hi I'm looking at cocoon and other property systems. I would like to get a nice library once for all. I want to also revisit Artefact stylesheets. I'm checking the semantics regarding the lookup of a property in a parent when it is not found in the receiver. I have the impression that when there is a parent access and modification should modify the same object: i.e., the parent if the key is found in the parent or the child if the property is found in the child. in cocoon we have a mix of the two semantics and I would like to get your feel about it. propertyAt: aKey "Answer the value of the property ==aKey==, raises an error if the property doesn't exist." ^ self propertyAt: aKey ifAbsent: [ self hasParent ifTrue: [ self parent propertyAt: aKey ] ifFalse: [self errorPropertyNotFound: aKey ]] propertyAt: aKey default: aBlock "Answer the value of ==aKey==. If the key have no entry I look on the parent or execute a block if i'm an orphan." ^ self propertyAt: aKey ifAbsent: [ self hasParent ifTrue: [ self parent propertyAt: aKey default: aBlock ] ifFalse: aBlock ] but propertyAt: aKey ifAbsent: aBlock "Answer the value of the property ==aKey==, or the result of ==aBlock== if the property doesn't exist." ^ self properties at: aKey ifAbsent: aBlock propertyAt: aKey ifAbsentPut: aBlock "Answer the value of the property ==aKey==, or if the property doesn't exist adds and answers the result of evaluating ==aBlock==." ^ self properties at: aKey ifAbsentPut: aBlock In PetitParser there is no lookup. But we can get back to this situation by just not setting a parent. My gut feeling is telling me that overriding on write is not really good because a client of the parent will not see the changes coming from a child. I thaought that stylesheet was supporting lookup but it does not testSubstyleAttributesOverride styleSheet at: #textColor put: #red. styleSheet > #sub > #subsub at: #textColor put: #blue. self assert:( styleSheet get: #textColor ) equals: #red. self assert:( styleSheet > #sub get: #textColor ) equals: #red. self assert:( styleSheet > #sub > #subsub get: #textColor ) equals: #blue. Does not work What you think? Stef
What is Cocoon? Phil <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaig...> Virus-free. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaig...> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> On Sat, Mar 18, 2017 at 1:18 PM, stepharong <stepharong@free.fr> wrote:
Hi
I'm looking at cocoon and other property systems. I would like to get a nice library once for all. I want to also revisit Artefact stylesheets.
I'm checking the semantics regarding the lookup of a property in a parent when it is not found in the receiver.
I have the impression that when there is a parent access and modification should modify the same object: i.e., the parent if the key is found in the parent or the child if the property is found in the child.
in cocoon we have a mix of the two semantics and I would like to get your feel about it.
propertyAt: aKey "Answer the value of the property ==aKey==, raises an error if the property doesn't exist."
^ self propertyAt: aKey ifAbsent: [ self hasParent ifTrue: [ self parent propertyAt: aKey ] ifFalse: [self errorPropertyNotFound: aKey ]]
propertyAt: aKey default: aBlock "Answer the value of ==aKey==. If the key have no entry I look on the parent or execute a block if i'm an orphan."
^ self propertyAt: aKey ifAbsent: [ self hasParent ifTrue: [ self parent propertyAt: aKey default: aBlock ] ifFalse: aBlock ]
but
propertyAt: aKey ifAbsent: aBlock "Answer the value of the property ==aKey==, or the result of ==aBlock== if the property doesn't exist."
^ self properties at: aKey ifAbsent: aBlock
propertyAt: aKey ifAbsentPut: aBlock "Answer the value of the property ==aKey==, or if the property doesn't exist adds and answers the result of evaluating ==aBlock==."
^ self properties at: aKey ifAbsentPut: aBlock
In PetitParser there is no lookup. But we can get back to this situation by just not setting a parent. My gut feeling is telling me that overriding on write is not really good because a client of the parent will not see the changes coming from a child.
I thaought that stylesheet was supporting lookup but it does not
testSubstyleAttributesOverride styleSheet at: #textColor put: #red. styleSheet > #sub > #subsub at: #textColor put: #blue. self assert:( styleSheet get: #textColor ) equals: #red. self assert:( styleSheet > #sub get: #textColor ) equals: #red. self assert:( styleSheet > #sub > #subsub get: #textColor ) equals: #blue. Does not work
What you think?
Stef
It is a lib to manage configuration like the one on pillar. Now cocoon is using magritte and this is a bit too much for my taste so I'm doing one iteration to produce a new lib where validation and runtime can be separated. Stef On Sat, Mar 18, 2017 at 3:44 PM, phil@highoctane.be <phil@highoctane.be> wrote:
What is Cocoon?
Phil
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On Sat, Mar 18, 2017 at 1:18 PM, stepharong <stepharong@free.fr> wrote:
Hi
I'm looking at cocoon and other property systems. I would like to get a nice library once for all. I want to also revisit Artefact stylesheets.
I'm checking the semantics regarding the lookup of a property in a parent when it is not found in the receiver.
I have the impression that when there is a parent access and modification should modify the same object: i.e., the parent if the key is found in the parent or the child if the property is found in the child.
in cocoon we have a mix of the two semantics and I would like to get your feel about it.
propertyAt: aKey "Answer the value of the property ==aKey==, raises an error if the property doesn't exist."
^ self propertyAt: aKey ifAbsent: [ self hasParent ifTrue: [ self parent propertyAt: aKey ] ifFalse: [self errorPropertyNotFound: aKey ]]
propertyAt: aKey default: aBlock "Answer the value of ==aKey==. If the key have no entry I look on the parent or execute a block if i'm an orphan."
^ self propertyAt: aKey ifAbsent: [ self hasParent ifTrue: [ self parent propertyAt: aKey default: aBlock ] ifFalse: aBlock ]
but
propertyAt: aKey ifAbsent: aBlock "Answer the value of the property ==aKey==, or the result of ==aBlock== if the property doesn't exist."
^ self properties at: aKey ifAbsent: aBlock
propertyAt: aKey ifAbsentPut: aBlock "Answer the value of the property ==aKey==, or if the property doesn't exist adds and answers the result of evaluating ==aBlock==."
^ self properties at: aKey ifAbsentPut: aBlock
In PetitParser there is no lookup. But we can get back to this situation by just not setting a parent. My gut feeling is telling me that overriding on write is not really good because a client of the parent will not see the changes coming from a child.
I thaought that stylesheet was supporting lookup but it does not
testSubstyleAttributesOverride styleSheet at: #textColor put: #red. styleSheet > #sub > #subsub at: #textColor put: #blue. self assert:( styleSheet get: #textColor ) equals: #red. self assert:( styleSheet > #sub get: #textColor ) equals: #red. self assert:( styleSheet > #sub > #subsub get: #textColor ) equals: #blue. Does not work
What you think?
Stef
participants (3)
-
phil＠highoctane.be -
Stephane Ducasse -
stepharong