Proposed changes.

Changes.md

@@ -9,7 +9,17 @@ Feel free to provide a PR with more proposed changes!
 ## Lesson 1
 
 ### Lecture
-- 
+- Rewrite "Each Jupyter notebook is a series of cells." to "Each Jupyter notebook is a series of text and code cells."
+  and then "To execute a cell, click ..." to "To execute a cell that contains Haskell code, click ...".
+- I did not understood the expression "... function definitions are trees of expressions" but when I watched the lecture 
+  it is explained very nicely. Can we add a statement like "For further explanation what are trees of expressions watch
+  the video lecture."?
+- I'm not sure if the title "What are functional programming languages" is a good choice. The definition we have is the 
+  same as on wikipedia for what is "functional programming". But on the web when you goole for "functional programming 
+  languages" it says that functional PLs offer the user the features of purely functional PLs, but do not enforce them. 
+  Also functional PLs do not implement lambda calculus under the hood as haskell does, where everthing is combinations  
+  of functions. My suggestion is to change the title from "Functional programming languages" to "Functional programming" 
+  and then possibly add a comment where we explain what is considered a functional programming language. 
 ### Homework
 - 
 
@@ -18,5 +28,59 @@ Feel free to provide a PR with more proposed changes!
 ### Lecture
 - Add short explanation about type classes after polymorphysm. Just enough so the students don't struggle until we cover them properly on the type classes lesson.
 - 
+### Homework
+- 
+
+## Lesson 3
+
+### Lecture
+- Some code when executed returns comments in the form of "Found: ... Why not: ...". Can we disable that?
+- Some cell results are not cleared. Thomas suggested that we should upload jupyter files such that we clear all previous
+  output from cells. Then also the comments from point 1 will not be seen when looking at the lesson only on github.
+- In the guards chapter add an example where you show it is possible to use more then one condition in a single guard line.
+  If you split them with a comma they are combined with a logical AND. But you can also combine them with a logical OR:
+### Homework
+- 
+
+## Lesson 4
 
+### Lecture
+- 
+### Homework
+- 
+
+## Lesson 5
+
+### Lecture
+- Noticed that the command ":t filter" gives "filter :: forall a. (a -> Bool) -> [a] -> [a]". If the student sees the forall 
+  statement we should explain what it is.
+- We can add an explanation how variable lookup works in Haskell and explain lexical scope. This could be in the lambda function
+  chapter, since you also use a lambda function to demonstrate this. 
+### Homework
+- 
+
+## Lesson 6
+
+### Lecture
+- 
+### Homework
+- 
+
+## Lesson 7
+
+### Lecture
+- 
+### Homework
+- 
+
+## Lesson 8
+
+### Lecture
+- In the comments where we write "-- Real definition" I would rather write "-- Actual Haskell definition" because the workd Real
+  can be dubious because up to this lesson the students did not looked at any Haskell source code. 
+- It would be nice to explain the phrases "sum types" and "record types" when explaning algebraic data types. They are often used
+  among programming language jargon.
+- Also we can explain the advantages of sum types over product types used in hierarchical design by imperative languages. We can 
+  show a code example thatneeds to be refactored by adding a type and how dificult it is when using product types in e.g. Java. 
 ### Homework
+- Why not include an example (the one that was scratched) where you show different ways how to present your data with sum types?