%session.Data with unlimited amount of indexes

/// Set value to %session.Data 
ClassMethod setValue(params...) As %Status
{
 quit:params<2 0
 set var="%session.Data("
 for i=1:1:params-1 set var=var_""""_params(i)_""","
 set $e(var,*)=")"
 set @var=params(params)
 quit $$$OK
}

Hey.
It's easier ?
```
ClassMethod setValue(params...) As %Status
{
  quit:params<2 0
  s name="%session.Data"
  for i=1:1:params-1 set:$GET(params(i))'="" name=$NA(@name@(params(i)))
  set @name=params(params)
  quit $$$OK
}
```

I'm not sure about what you mean with "unlimited amount of indexes"...

first, there is a limit of 255 for the parameters, this means you can have 

do ..setValue(key1,key2,...key254,value)

but you can't have 

 do ..setValue(key1,key2,...key254,key255,value)

second, if you meant to have many-many values (in sense of, we have to much data)

  do ..setValue(key1,value1)
  do ..setValue(key2,value2)
  // etc.

then, at some point you will reach the and of the available RAM (incl. swap/paging space.  Usually swap/paging space is much less then the space for the real data).

thirdly, if you meant variable number of indexes (in sense of variable number of parameters) then I can just refine Robert's solution to

ClassMethod setValue(params...) As %Status
{
   set base=$name(%session.Data)
   for i=1:1:params-1 { set base=$name(@base@(params(i)))
   set @base=params(params)
   quit 1
}

In case, you have both, variable number of indices and too much data then you could use a mix of the above with data placed in a temp file.

Somewhere, at the program start, let you point %sessionData to a temp file

   set %sessionData=$nam(^||SessionTemp)

and then consider this in the setValue method

ClassMethod setValue(params...) As %Status
{
   set bas=%sessionData
   ...
}

Of course, in your application, you have to change only those %session.Data(...) to  @%sessionData@(...)  which uses the "variable-big-data" part of %session.Data(). All other (the standard ones) stay unchanged.

I'd mimic %DispatchSetMultidimProperty signature. Shame local cannot be casted into a multi-argument call. Wrap in $g if values can be skipped.

/// do ##class().Test()
ClassMethod Test()
{
    kill ^data
    do ..setValue("val", "key1")
    do ..setValue("val", "key1", "key2", "key3", "key4")
    zw ^data
}

ClassMethod setValue(val, args...)
{
    if args=1 {
        set ^data(args(1)) = val
    } elseif args=2 {
        set ^data(args(1), args(2)) = val
    } elseif args=3 {
        set ^data(args(1), args(2), args(3)) = val
    } elseif args=4 {
        set ^data(args(1), args(2), args(3), args(4)) = val
    }
}

Another option just for the fun:

Include %SYS.PTools.Stats

Class dc.test [ Abstract ]
{

ClassMethod setValue(args...) As %Status
{
  quit:args<2 $$$ERROR($$$DataMissing)

  $$$convertArrayToList(args,list)
  quit:$listlength(list)'=args $$$ERROR($$$RequiredArgumentMissing)
  
  set $list(list,*,*)="",
         var=##class(%Utility).FormatString(list),
         $extract(var,1,3)=$name(%sessionData), ##; or $name(%session.Data)
         @var=args(args)
  quit $$$OK
}

/// do ##class(dc.test).Test()
ClassMethod Test()
{
  new %sessionData

  try{

    do $system.OBJ.DisplayError(..setValue("key1", "val1")),
          $system.OBJ.DisplayError(..setValue("key1", "key2", "key3", "key4", "val2")),
          $system.OBJ.DisplayError(..setValue("key1", "key2", , "key4", "val3")),
          $system.OBJ.DisplayError(..setValue())
    
    write !
    zwrite %sessionData
  }
  catch(ex){
    write ex.DisplayString(),!
  }
}

}