a. A programming language establishes a contextfree requirement for a program to be legal if and only if that requirement could be captured conveniently by a contextfree grammar.

b. It establishes a contextsensitive requirement if and only if that requirement is not contextfree and could be checked (by a translator or interpreter) before runtime.

c. It establishes a runtime requirement if and only if it is a requirement for a program to be legal and the requirement can always be detected and reported at runtime, but not before then.

Note that a contextfree requirement could (and should) be checked before runtime. For each of the three requirement categories defined above, describe a requirement on Core language programs that belongs in the category. In each case, provide a clear argument that establishes why the requirement you chose belongs in the category you chose.

Core: Simple prog. language like Java, C, C++, etc.