expression ==> self_expression | local_expression | call_expression | void_expression | void_test_expression | new_expression | create_expression | array_expression | and_expression | or_expression | sugar_expression | while!_expression | until!_expression | break!_expression | except_expression | initial_expression | result_expression | closure_create_expression
Sather expressions are used to compute values or to cause side-effects. If they return a value, then they have a return type that is either explicitly declared or inferred from context.
Example 7-1. Example:
self_expression ==> self
self expressions may appear in the bodies and in the pre and post clauses of routines and iters. They return the object on which the method was called. The return type is the type in which the method appears.