A few changes have been made to make Modula-2 programs easier to debug.
This is done primarily via loosening its type strictness:
Unlike in standard Modula-2, pointer constants can be formed by
integers. This allows you to modify pointer variables during
debugging. (In standard Modula-2, the actual address contained in a
pointer variable is hidden from you; it can only be modified
through direct assignment to another pointer variable or expression that
returned a pointer.)
C escape sequences can be used in strings and characters to represent
non-printable characters. GDB prints out strings with these
escape sequences embedded. Single non-printable characters are
printed using the `CHR(nnn)' format.
The assignment operator (:=) returns the value of its right-hand
argument.
All built-in procedures both modify and return their argument.