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∵ Mari-chan ∴ 2022-03-08 ∞ 2'
Programs conjure processes.
Lisp languages call processes "procedures".
It blurs the idea between passive data and active process, making it a good language to write programs that must manipulater other programs as data (such as interpreters and compilers).
There are two kinds of elements in programming: procedures and data.
Omg, what a catastroph. Lisp implements some weird kind of RPN, but not really. Code like (+ 10 12 12) is valid. It's a tree structure eval. I think it's the same for every data thing on Clojure at least, according to Nick.
Declaring vars define var 2.
The general form of a procedure definition is:
(define (<name> <formal parameteres>) <body>)
#e.g
(define (square x) (* x x))
This is the ugliest square function definition I ever saw in my entire life.
I don't really understand (or care) for the difference between normal-order eval and applicative-order eval, should I? Seems like I should cause it's gonna be used later on.
Ifs:
(define (abs x)
(cond ((> x 0) x)
((= x 0) 0)
((< x 0) (-x))))
It's basically an if, if else, if else.
You can also:
(define (abs x)
(cond ((< x 0) (-x))
(else x)))
Or:
(define (abs x)
(if (< x 0)
(-x)
x))
You can use and, or, not...
Processes are generated by procedures. A procedure is a pattern for the local evolution of a computational process.
Here's an example of factorial function:
(define (factorial n)
(if (= n 1)
1
(* n (factorial (- n 1)))))
I'll stop mentioning how ugly everything looks as this will get in the way of me learning this.
Just had a cool insight, about the shape of the outputs of functions! Big O notation is just a mathematical expression of their shapes. Kinda cool.
Should we code the example on page 40? Should I? Probably? I wonder if that's how you create a map...
Seems like the example on page 50 might offer some interesting insights on Big O, but I don't feel like it right now8