In 4.5, we extended the example language with closures and implemented these in the interpreter. Extend the type-checking functions in Figs. 5.2–5.4 to statically type check the same extensions. Hint:...

In 4.5, we extended the example language with closures and

implemented these in the interpreter.

Extend the type-checking functions in Figs. 5.2–5.4 to statically type check the

same extensions.

Hint: Check a function definition when it is declared.