org.finos.morphir.ir

A value of type NeedAttributes[A] provides implicit evidence that a node with attributes type A needs attribute values, that is, that A is not equal to Any.

In functional programming data and logic are treated the same way and we refer to both as values. This module provides the building blocks for those values (data and logic) in the Morphir IR.

If you use Elm as your frontend language for Morphir then you should think about all the logic and constant values that you can put in the body of a function. Here are a few examples:

myThreshold =
   1000

min a b =
 if a < b then
   a
 else b

addTwo a = a + 2

All the above are values: the first one is just data, the second one is logic and the last one has both logic and data. In either case each value is represented by a Value expression. This is a recursive data structure with various node types representing each possible language construct. You can check out the documentation for values below to find more details. Here are the Morphir IR snippets for the above values as a quick reference:

myThreshold = Literal () (WholeNumberLiteral 1000)

min a b = IfThenElse () (Apply () (Apply () (Reference () (fqn "Morphir.SDK" "Basics" "lessThan")) (Variable () [ "a"
]) ) (Variable () [ "b" ]) ) (Variable () [ "a" ]) (Variable () [ "b" ])

addTwo a = Apply () (Apply () (Reference () (fqn "Morphir.SDK" "Basics" "add")) (Variable () [ "a" ]) ) (Literal ()
(WholeNumberLiteral 2))