Assume that we have calculator erpressions expressions that

Assume that we have calculator erpressions, expressions that follow the syntax E (const num) (add E E) (sub E E) (mult E E) (div E E) Here are two example calculator expressions: This BNF notation for inductive sets will be explored in more detail later on in the course.

Solution

Fold expression is a notation where we can write entire statement into single line,
where starts with inititalizing all parameters , then followed by functions.

foldc: (A-> B) B (add AA) (sub AA) (mult AA (div AA)