The article tries to make its point with unnecessarily complex code examples. They seem to be locked in a C way of thinking. But Pascal was created about the same as C and had proper types.

Strings could be represented as length checked arrays. They could come in two types, short ones, having a length byte at the beginning and are limited to 256 elements, and long ones, having an "int" size marker and corresponding length limits. The type handling could be handled by the compiler, the length() function would always return an int, and the elements addressed by a[i]. Thats it. This would have saved us more than 3 decades of nasty bugs if not security problems.