Easy way to rename a map element?

[jacdelad]

Hi,

is there an easy way to rename a map element? A structured map, of course. Right now I copy all values one by one into the new element.

[STARGÅTE]

You mean rename the key?
Not to my knowledge.

But you can easily do
MyMap(NewKey) = MyMap(OldKey)
to copy the whole structure.

[jacdelad]

Yes, the key.
...does this not just copy the pointer to the map element? What about maps and lists within the map element?

[STARGÅTE]

Yes, the key.
...does this not just copy the pointer to the map element? What about maps and lists within the map element?

No, it is the short form for CopyStructure(@MyMap(OldKey), @MyMap(NewKey), MapStructure).
It is a full copy of all structure fields, string, lists etc.

[idle]

Better to use a map with integer to heap allocated structures then use
findmapelement deletemapelemnt and addmapelement

Code: Select all

Procedure RenameMapElement(Map mp(),oldkey.s,newkey.s) 
  Protected *ele.integer,value 
  *ele = FindMapElement(mp(),oldkey) 
  If *ele 
    value = *ele\i 
    DeleteMapElement(mp(),oldkey) 
    AddMapElement(mp(),newkey)
    mp() = value 
    ProcedureReturn mp()  
  EndIf  
EndProcedure  

Global NewMap foo.i() 

foo("abc") = 123  
foo("bcd") = 234 

RenameMapElement(foo(),"abc","cba") 
Debug foo() 

;hack it but only if it's static 

Structure mapelement 
  *next 
  key.s 
EndStructure   

*ele.mapelement = FindMapElement(foo(),"cba") - SizeOf(mapelement) 
PokeS(@*ele\key,"abc") 

ForEach foo() 
  Debug MapKey(foo()) + " " + Str(foo()) 
Next   

You can hack the mapkey name and get it in a foreach but it will break the functionality of the map so you can only do it safely when the map is static and only once.

[jacdelad]

Thanks very much!