Chapter 15

1. Control structures in very high-level and domain-specific languages had better be a lot more powerful than just if statements and loops; otherwise, programmers would be better off just coding in a mainstream language.
2. We provided some examples in which control structures provided defaults for 0parameters or ensured an open resource was closed afterward. Domain-specific control structures can certainly provide additional high-level semantics, such as performing domain-specific input/output or accessing specialty hardware in a way that is difficult to accomplish within the context of a mainstream control flow.
3. The application domain is string analysis. Maybe some additional operators or built-in functions would improve Unicon's expressive power for string analysis. Can you think of any candidates you could add to the six-string analysis functions or the two position-moving functions? You could easily run some statistics on common Icon and/or Unicon applications...