Note that you need to

3) Register Monitor System Classes

before enabling them.

Great article.

Can Native API call ObjectScript class methods?

From docs:

Procedure blocks enforce variable scoping: methods cannot see variables defined by their caller. New applications use procedure blocks; non-procedure blocks exist for backwards compatibility.

Does your class (base class) or method has these modifiers:

• ProcedureBlock
• PublicList

?

For me the main acceptable case of foreach iteration is business objects - for example we receive array of results and must process them. In that case we, of course, must iterate over them, no way around it.

Everything static: constraints, enums, dictionaries, etc... should be (and usually could be) used without foreach iteration.

I agree that there are cases where we need to do something over each element of the collection.

But you said:

constants, static arrays in algorithms, e.g. arbitrary dictionaries

Which implies that foreach iteration is not desired here.

Anyways, in that case what does matter is size.

If you're sure that it would be less than $$$MaxStringLength then you can use $lb, otherwise use locals (which can be converted to ppg/globals easily).

TOP 100.

In EntityBrowser.API class set PAGESIZE parameter to 100 and compile the class.

1. Before we iterate over rows we need to determine column type, the example is about that.

Here's an example of what I'm talking about.

2. You want to avoid full scan as much as possible. Two techniques for that are:

• knowing position
• knowing key

And that determines the type of structure used.

If you don't know either you need to think about possible algorithm improvements.

You can try your luck with $stack.

What's the use case anyway?

It depends on a use case.

• For access by position use $lb.
• For access by key use locals.

Consider the scenario of iterating over the result set. You need to do two things:

• Convert value based on a column datatype
• If a value is special translate it

To solve the first one (and assuming we get values by position number) the most efficient solution would be iterating over metadata once and building something like this:

set columns = $lb("int", "bool", "str", ...)

Then in each row we can easily get datatype by:

for i=1:1:colCount {
  set dataType = $lg(columns, i)
  set value = rs.Get(i)
}

Now for a second part - value translation, locals are great here. We prep our translator:

set local(1) = "a"
set local("hi") = "world"

and replace the value if needed

set:$data(local(value), newValue) value = newValue

Ok.

Parameter is about 6x faster btw:

ClassMethod GetMonthList1() As %List
{
    Quit $Listfromstring("January,February,March,April,May,June,July,August,September,October,November,December")
}

ClassMethod GetMonthList2() As %List [ CodeMode = expression ]
{
$Listfromstring("January,February,March,April,May,June,July,August,September,October,November,December")
}

ClassMethod GetMonthList3() As %List [ CodeMode = expression ]
{
$lb("January","February","March","April","May","June","July","August","September","October","November","December")
}

Parameter GetMonthList = {$lb("January","February","March","April","May","June","July","August","September","October","November","December")};

ClassMethod Time2()
{
    for method = 1:1:3 {
        set start = $zh
        
        for i=1:1:10000 {
            set result = $classmethod(,"GetMonthList" _ method)
        }
        
        set end = $zh
        
        write $$$FormatText("Method: %1, time: %2", "GetMonthList" _ method, end - start),!
        
    }
    
    set start = $zh
    
    for i=1:1:10000 {
        set result = ..#GetMonthList
    }
    
    set end = $zh
    
    write $$$FormatText("Parameter, time: %1",  end - start),!
}

Results

Method: GetMonthList1, time: .007255
Method: GetMonthList2, time: .006717
Method: GetMonthList3, time: .003878
Parameter, time: .000605

Why

ClassMethod GetMonthList1() As %List
{
    Quit $Listfromstring("January,February,March,April,May,June,July,August,September,October,November,December")
}

instead of

ClassMethod GetMonthList3() As %List
{
 Quit $lb("January","February","March","April","May","June","July","August","September","October","November","December")
}

Not yet.

Check RESTForms project, it does similar things (articles: part1, part2).

Starting from 2019.2 there's a %JSON.Adapter, for automatic bidirectional JSON<>Object transformation.