Summary of important points in Hw1

• HW 1 is about learning to read and modify new languages.

• Editing, Compiling and Executing Python and Haskell.

• Language e1 is an expression language.
  1. The meaning of a program is a simple value. Here it is an integer.
  2. There are no variables or any other kind of state.
  3. There are no side effects.
  4. There are no control structures.
  5. The language is compositional. The meaning of a program is computed solely from the meaning of its parts. There is no context that can change the meaning of the program.

• The idea that a anguage can compile to an intermediate abstract machine. I.e. in this example the stack machine.

• A processor has a number of stages.
  1. Parsing from a file to an intermediate data structure.
  2. Building an input to the abstract machine.
  3. Executing the abstract machine on this input
  4. Communicating the result to the real world.