| |
|
| | (ns e2-46-to-51
(:use clojure.test))
data abstraction definitions
| | (defn make-vect [x y]
[x y])
|
| | (defn xcor-vect [v]
(first v))
|
| | (defn ycor-vect [v]
(second v))
|
| | (deftest test-make-vect
(let [zo (make-vect 0 1)]
(is (= 0 (xcor-vect zo)))
(is (= 1 (ycor-vect zo)))))
|
| | (def a {:data [(make-vect 0 0) (make-vect 1 1)] :add (make-vect 1 1) :sub (make-vect -1 -1)})
(def b {:data [(make-vect 2 3) (make-vect 5 4)] :add (make-vect 7 7) :sub (make-vect -3 -1)})
|
| | (defn add-vect [v1 v2]
(make-vect
(+ (xcor-vect v1) (xcor-vect v2))
(+ (ycor-vect v1) (ycor-vect v2))))
|
| | (defn sub-vect [v1 v2]
(make-vect
(- (xcor-vect v1) (xcor-vect v2))
(- (ycor-vect v1) (ycor-vect v2))))
|
| | (defn scale-vect [v x]
(make-vect (* (xcor-vect v) x) (* (ycor-vect v) x)))
|
| | (deftest test-vect-ops
(is (= (add-vect (first (get a :data)) (second (get a :data))) (get a :add)))
(is (= (add-vect (first (get b :data)) (second (get b :data))) (get b :add)))
(is (= (sub-vect (first (get a :data)) (second (get a :data))) (get a :sub)))
(is (= (sub-vect (first (get b :data)) (second (get b :data))) (get b :sub))))
|
| | (def va (make-vect 1 1))
|
| | (defn make-frame [o e1 e2]
(list o e1 e2))
|
| | (defn origin-frame [f]
(first f))
|
| | (defn edge1-frame [f]
(second f))
|
| | (defn edge2-frame [f]
(second (next f)))
|
| | (deftest test-frame
(is (= (origin-frame (make-frame va va va)) va))
(is (= (edge1-frame (make-frame va va va)) va))
(is (= (edge2-frame (make-frame va va va)) va)))
|
| | (defn make-frame2 [o e1 e2]
(cons o (cons e1 e2)))
This is a degenerate abstraction for frames - the e2 part becomes the tail
of a list created by (cons e1 e2).
user=> (cons [1 1] (cons [2 2] [3 3]))
([1 1] [2 2] 3 3)
| |
|
| | (defn origin-frame2 [f]
(first f))
|
| | (defn edge1-frame2 [f]
(second f))
|
| | (defn edge2-frame2 [f]
(let [remaining (next (next f))]
(list (first remaining) (second remaining))))
|
| | (deftest test-frame2
(is (= (origin-frame2 (make-frame2 va va va)) va))
(is (= (edge1-frame2 (make-frame2 va va va)) va))
(is (= (edge2-frame2 (make-frame2 va va va)) va)))
Another exercise in abstraction and concept layering...
| |
|
| | (defn make-segment [a b]
(list a b))
|
| | (defn start-segment [s]
(first s))
|
| | (defn end-segment [s]
(second s))
|
| |
|
| | (defn segments->painter [segs] nil)
|
| | (defn paint-frame [f]
((segments->painter [(make-segment (make-vect 0 0) (make-vect 0 1))
(make-segment (make-vect 0 1) (make-vect 1 1))
(make-segment (make-vect 0 0) (make-vect 1 0))
(make-segment (make-vect 1 0) (make-vect 1 1))]) f))
|
| | (defn paint-frame [f]
((segments->painter [(make-segment (make-vect 0 0) (make-vect 1 1))
(make-segment (make-vect 0 1) (make-vect 1 0))]) f))
| | |