Practical Foundations for Programming Languages 是 Robert Harper 的一本书，而这是我写的笔记 2
Chapter 4 Statics ¶
Most programming languages exhibit a phase distinction between the static and dynamic phases of processing. The static phase consists of parsing and type checking to ensure that the program is well-formed; the dynamic phase consists of execution of well-formed programs. A language is said to be safe exactly when well-formed programs are well-behaved when executed.