BNF

-> program -> start stop -> empty | var Identifier = Integer -> . | : Identifier -> + | - | / | * | -> % | -> ( ) | Identifier | Number -> -> empty | -> | | | | | -> read Identifier . -> print . -> iff ( ) -> iter ( ) -> let Identifier = . -> < | < < | > | > > | = = | =

In this grammar there is no function call. Suppose we want to change function calls so that they evaluate to some returned data, and this data could be used the

same way as variables are used in expressions (not left of assignment). For example, you could write

x = 2 + F1(5) * 3

which, assuming that F1(5) returns 10, should put 32 into x.

Show changes needed in syntax and explain semantics of function call.