Lecture 1

Today, we give an overview over the entire class, explain why we use ML, and start the technical material of the class by talking about expressions which consist of values and operations. Expressions can be executed or evaluated, and results will always be values.

When we write a program, we would like to know that it is operating correctly. We ourselves however, don't really want to prove any theorems about our programs, on the contrary, we just want to be able to write good code. Wouldn't it be nice, if the compiler warns you before you make mistakes? I mean obvious mistakes? This is exactly what ML tries to do. It looks at your code, tries to figure out "if it make sense", if yes, it allows you to execute it, otherwise it prevents you from execution and gives you an error message. To is effect it uses types, a very important concept that underlies ML and therefore this course.

Reading: Programming Standard ML. Chapter 2: Types, Values, Effects.