Code in F#.

Implement the function desugarChoose : expr -> expr, which should convert the given expression to an equivalent expression that does not use Choose. You will need to use Try and Fail. Be careful to ensure that you desugar all subexpressions.

let rec desugarChoose (e : expr) : expr =

failwith "Not implemented"

Here is desugarChoose with Choose :

let e2 =

desugarChoose (Plus (Var "y",

Choose

[ If (LessThan (Var "x", Num 0), Fail, Var "x")

; If (LessThan (Plus (Var "x", Var "y"), Num 0), Fail, Plus (Var "x", Var "y"))

; Choose [ Var "y" ]]))