Completed the 1st chapter of sicp.
I really appreciate the exercises within each subsections, because I can feel that they are well designed. I used to have the same feeling when I did the homework from Dan’s course of programming languages. The exercises make the general concepts concrete and doable.
The abstraction is far from merely making the code more structured and readable. It is a design choice. Sometimes, it takes experience to find out where should be abstracted. And sometimes, it takes much more endeavors than simply mix everything together. But once the choice of abstraction is right, the program becomes clearer, and it increases many degrees of freedom for the design afterwards.