Programming with Types

List of Figures

Chapter 1. Introduction to typing

Figure 1.1. A sequence of bits can be interpreted in multiple ways.

Figure 1.2. The sequence of bits typed as a signed 16-bit integer. The type information (16-bit signed integer) tells the compiler and/or run time that the sequence of bits represents an integer value between -32768 and 32767, ensuring the correct interpretation as -15709.

Figure 1.3. Source code is transformed by a compiler or interpreter into code that can be executed by a run time. The run time is a physical computer or a virtual machine, such as Java’s JVM, or a browser’s JavaScript engine.

Figure 1.4. Declaring a type correctly, we can disallow invalid values. The first type is too loose and allows for values we don’t want. ...