The size, in bytes, of a stack frame for this procedure, including
formal parameters, return address, control pointer, register save area,
and local variables.
Tests whether this SimpleExprNode represents something that may be
on the left-hand-side of an assignment, or passed to an OUT or INOUT
parameter of a procedure or function.
An AST node representing a function or procedure declaration:
"FUNCTION name(parameters) RETURN type IS decls BEGIN stmts END;" or
"PROCEDURE name(parameters) IS decls BEGIN stmts END;".