ArithLangis a language with simple arithmetic expressions with the followingconcrete syntax.

Expression ::= Number

::= Expression + Expression

::= Expression - Expression

::= Expression * Expression

::= Expression / Expression

InArithLang's syntax,Numberdenotes a number and+,-, *and/denote arithmetic plus, minus, multiplication and division operations.

Design and define a datatype calledExpressionto represent theabstract syntaxofArithLang.

Hint:You can usedefine-datatypeconstruct to define the abstract syntax.