11.4: Assertion Style
Syntactically, pre- and post-conditions are simply boolean expressions, with a few extensions.
(1) The ‘old’’ qualifier introduced later in OSC Ch. 11, is used to deal with temporal order.
(2) The semicolon is used to represent conjunctive and: n > 0 ; x /= Void (Eiffel syntax)
(nɬ) && (x !=Void) (‘C’ syntax)
Meyer (Eiffel) also names each clause, for readability and ease of reference. For example:
(The semicolon is optional at the end of a line.)