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__Change meta function

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Guest

Post subject:

Posted: October 20th, 2011, 7:02 pm

This worked but it's getting way complicated. So I think __Change can simplify it.

Code:

Obj := { "": { base: { property : "value" } }
      , base: { _NewEnum : func("MyEnum")
         , myfunc : func("myfunc")
         , __Set : func("MySet")
         , __Get : func("MyGet") }}

Obj.a := 1   
Obj.a := 2     
Obj.b := 3   

msgbox % Obj.Property  

Obj.myfunc()     
    
For k, v in Obj
   msgbox %k% : %v%
   
MyEnum(this){
   Return this[""]._NewEnum()
}
MySet(this, key, value){
   msgbox % "Function: `t" A_ThisFunc "`nEdited key: `t" key "`nPassed value:`t" value
    return this["",key]:=value
}
MyGet(this, key){
   return this["",key]
}
myfunc(this, params*) {
   msgbox % "Function: " A_ThisFunc
}

fragman wrote:

I'm not quite sure why it's not getting the property from the base object though.

It's because it reads Obj[""].base instead of Obj.base.

Quote:

Btw: Why not use class syntax?

I don't have much of a meaning for it. I would go with a simpler way.

HotkeyIt, It also works. Thanks.

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fragman

Post subject:

Posted: October 20th, 2011, 10:22 pm

Joined: October 13th, 2009, 10:09 pm
Posts: 1389

Anonymous wrote:

fragman wrote:

I'm not quite sure why it's not getting the property from the base object though.

It's because it reads Obj[""].base instead of Obj.base.

It should not do that in my example since I specifically exclude base.

Anonymous wrote:

Quote:

Btw: Why not use class syntax?

I don't have much of a meaning for it. I would go with a simpler way.

I actually think that class syntax is much more readable than defining functions manually as keys. Using class syntax, everything that belongs together is confined in a single structure, including functions.

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Guest

Post subject:

Posted: October 20th, 2011, 10:44 pm

fragman wrote:

Anonymous wrote:

fragman wrote:

I'm not quite sure why it's not getting the property from the base object though.

It's because it reads Obj[""].base instead of Obj.base.

It should not do that in my example since I specifically exclude base.

The property isn't included in the base object of Obj[""] and MyGet() was redirecting the reference to Obj[""]. That's why the message box was empty. I can't find a better explanation than that. If you use a debugger, you can see it with Step Into.

Quote:

Anonymous wrote:

Quote:

Btw: Why not use class syntax?

I don't have much of a meaning for it. I would go with a simpler way.

If there is a working example that makes me think it is simpler, there is no reason for me to stick with the complex method.

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fragman

Post subject:

Posted: October 20th, 2011, 11:24 pm

Joined: October 13th, 2009, 10:09 pm
Posts: 1389

You're right, I was thinking that you had stored Property in obj.base instead of obj[""]. Simple class draft with similar functionality, untested though:

Code:

Obj := new CObject()

msgbox % Obj.Property  

Obj.myfunc()      

For k, v in Obj 
   msgbox %k% : %v% 

class CObject
{
   a := 1
   b := 3
   __New()
   {
      this.Insert("", {Property : "value"}) ;Insert like this to prevent triggering __Set
   }
   __Get(key)
   {
      return this["",key] 
   }
   __Set(key, Value)
   {
      msgbox % "Function: `t" A_ThisFunc "`nEdited key: `t" key "`nPassed value:`t" value 
      return this["",key]:=value 
   }
   _NewEnum()
   {  
      Return this[""]._NewEnum() 
   }
   myfunc(params*) { 
      msgbox % "Function: " A_ThisFunc 
   }
}

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Guest

Post subject:

Posted: October 21st, 2011, 12:45 am

Code:

obj := new NotifyChange

obj.a := 1
obj.a := 2
obj.b := 3

For k, v in obj
   msgbox %k% : %v%

msgbox % Obj.Property  

Obj.myfunc()     

Return   
   
Class NotifyChange {

    __New(){
        ObjInsert(this,"",{ base: {property : "value"} })
    }
    __Set(key, value){
      msgbox % "Function: `t" A_ThisFunc "`nEdited key: `t" key "`nPassed value:`t" value
        return this["",key]:=value
    }
    __Get(key){
        return this["",key]
    }
   _NewEnum(){
      Return this[""]._NewEnum()
   }
   myfunc(params*) {
      msgbox % "Function: " A_ThisFunc
   }   
}

fragman wrote:

You're right, I was thinking that you had stored Property in obj.base instead of obj[""].

Sounds like you still not getting it but it proves that the workaround is not intelligible and justifies the suggestion.

Quote:

Simple class draft with similar functionality, untested though:

Thanks but your code does not work.

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fragman

Post subject:

Posted: October 21st, 2011, 11:57 am

Joined: October 13th, 2009, 10:09 pm
Posts: 1389

You're right, it was just a quick draft. I actually tested now and here's a working version:

Code:

Obj := new CObject() 

msgbox % Obj.Property  

Obj.myfunc()      

For k, v in Obj 
   msgbox %k% : %v% 

class CObject 
{
   
   __New() 
   { 
      this.Insert("",{})
      this[""].Insert("Property", "value") ;Insert like this to prevent triggering __Set 
      this.a := 1 
      this.b := 3 
   } 
   __Get(key) 
   { 
      if(key!="")
         return this["",key] 
   } 
   __Set(key, Value) 
   { 
      msgbox % "Function: `t" A_ThisFunc "`nEdited key: `t" key "`nPassed value:`t" value 
      obj := 
      return this["",key] := Value
   }
   _NewEnum() 
   {
      Return this[""]._NewEnum() 
   } 
   myfunc(params*) { 
      msgbox % "Function: " A_ThisFunc 
   } 
}

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Guest

Post subject:

Posted: October 21st, 2011, 8:31 pm

You are not seeing the problem, which had been already solved.

I wrote:

the __Get meta function prevents base properties from being retrieved. Any workaround?

See the class example in my previous post; the For-loop does not retrieve Obj.Property but msgbox % Obj.Property does. That's the reason the base object was used.

If we could simply use this.base.haskey(key) in the __Get meta function without infinite recursion, we would have much simpler solution. That's why this suggestion is also important, which you seem not to get it.

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fragman

Post subject:

Posted: October 22nd, 2011, 11:25 am

Joined: October 13th, 2009, 10:09 pm
Posts: 1389

i just wanted to show an example using class syntax. As i said before you can specifically exclude the base key and proxy object key from __Get to prevent recursion, then you can access it from within __Get without any issues. It's a bit annoying that we need to use proxy objects for tasks like this but handling it is not much of an issue really once it's clear how to do it.

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Guest

Post subject:

Posted: October 22nd, 2011, 6:22 pm

fragman wrote:

As i said before you can specifically exclude the base key and proxy object key from __Get to prevent recursion, then you can access it from within __Get without any issues.

I think you are not seeing the problem but can you show how? FYI, the examples you posted didn't solve the problem.

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fragman

Post subject:

Posted: October 22nd, 2011, 8:40 pm

Joined: October 13th, 2009, 10:09 pm
Posts: 1389

just make sure not to explicitly return a value if the requested key is "base". If you don't explicitly insert a key named base via objinsert base is handled differently from other keys. I can post an example tomorrow if needed when i get back to a computer.
btw, does the class i posted before not enumerate "property"? i think it does but i can't check right now...

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