To display the type of a value:

Use the [Null->Type] method. The following example stores values of different types in an array, then fetches the type for each value.

Code

local(values = array('Hello', 123, 123.456, Null))
with v in #values 
do => {^
    #v + ': ' + #v->type + '\r'
^}

Result

Hello: string
123: integer
123.456000: decimal
: null