- Existence of an abstraction to which values can be converted.
- This abstraction provides operations to (1) wrap around values, so that they become the abstraction; (2) bind itself to functions, so to establish sequences of functions; and (3) unwrap the value, so to examine the final result.
- Larger problem is solved as a pipeline of functions bound together, with unwrapping happening at the end.
- Particularly for The One style, the bind operation simply calls the given function, giving it the value that it holds, and holds on to the returned value.
9.2 A Program in this Style
1 #!/usr/bin/env python
2 import ...