Announcing LAMBDAs to Production and Advanced Formula Environment, A Microsoft Garage Project

As I see it, LET and LAMBDA have changed the nature of Excel formulas utterly, but the GUI/IDE has not kept up with the calculation engine.  I would argue that a complete rethink is required but that is fraught with user acceptance issues.

The AFE is a tool that has allowed ideas to be prototyped with sufficient success that it is considered to worth making it available to users.  That is not the same as fully integrated functionality that has been internationalised, so any limitations within the editor will be present in the AFE.

However, it is quite possible to develop Lambda functions directly on the worksheet and I do it quite a lot, so all is not lost if the AFE does not work in your particular locale. An example such development might be

= LET(
Sumλ; LAMBDA(s;v; SUM(s;v));
Accumulateλ; LAMBDA(values;v₀; SCAN(v₀;values; Sumλ));
Accumulateλ(list;100)
)

The key is that LET is used to provide a formula-local name space.

The next line defines a Lambda function with the name Sumλ [please excuse my use of the Greek alphabet from the symbol menu, I have it in my autocorrect to replace "\lambda"].
Once that is done, the new function is used within the definition of a further Lambda function Accumulateλ.
Only when that is done, have I called the function to accumulate a list of credit/debits to form a running balance.

So, I recommend using LAMBDA functions even if you can't access the AFE, just avoid Name Manager until the Lambda function is tried and tested.