first session

This commit is contained in:
Peter Tillemans 2024-03-12 00:44:56 +01:00
parent bd91b8fe69
commit 7c76131b8d
7 changed files with 193 additions and 0 deletions

2
3_hello_scheme.scm Normal file
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(display "Hello, World!\n")

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4_basic_types.scm Normal file
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(+ 1 2)
(/ 10 2)
(/ 2 3)
(+ 1 8 10)
(* (- 8 (/ 30 5)) 21)

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5_variables_procedure.scm Normal file
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;; -*- geiser-scheme-implementation: guile -*-
(define name "Jane")
(string-append "Hello, " name "!") ; "Hello, Jane!"
(define (greet name)
(string-append "Hello, " name "!"))
; #<unspecified>
(greet "Jane") ; "Hello, Jane!"
(greet "Samantha") ; "Hello, Samantha"
((lambda (name) (string-append "Hello, " name "!")) "Jane")
; "Hello, Jane!"
((lambda (name) (string-append "Hello, " name "!")) "Samantha")
; "Hello, Samantha!"
(let ((name "Horace"))
(string-append "Hello, " name "!")) ; "Hello, Horace!"
(let* ((name "Horace")
(greeting (string-append "Hello, " name "!")))
(string-append greeting " How are you?"))
; "Hello, Horace! How are you?"
(apply + '(1 2 5))
; 8
(define (chatty-add chatty-name . nums)
(format #t "<~a> If you add those together you get ~a."
chatty-name
(apply + nums)))
(chatty-add "Jane" 1 2 5) ; #t
(define* (shopkeeper thing-to-buy
#:optional (how-many 1)
(cost 20)
#:key (shopkeeper "Sammy")
(store "Plentiful Great Produce"))
(format #t "You walk into ~a, grab something from the shelves,\n" store)
(display "and walk up to the counter.\n\n")
(format #t "~a looks at you and says, " shopkeeper)
(format #t "'~a ~a, eh? That'll be ~a coins!'\n" how-many thing-to-buy (* how-many cost)))
(shopkeeper "apples")
(shopkeeper "bananas" 10 28)
(shopkeeper "screws" 3 2 #:shopkeeper "Horace" #:store "Horace's Hardware")
(define (add-and-multiply x y)
(values (+ x y) (* x y)))
(add-and-multiply 2 8) ; 10 16
(define-values (added multiplied) (add-and-multiply 2 8))
added ; 10
multiplied ; 16

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;; -*- geiser-scheme-implementation: guile -*-
(string? "apple") ; #t
(string? 5) ; #f
(string? 'apple) ; #f
(define (string-enthusiast obj)
(if (string? obj)
"Oh my gosh you gave me A STRING!!!"
"That WASN'T A STRING AT ALL!!! MORE STRINGS PLEASE!"))
(string-enthusiast "apple") ; "Oh my gosh you gave me A STRING!!!"
(string-enthusiast 5) ; "That WASN'T A STRING AT ALL!!! MORE STRINGS PLEASE!"
(> 8 9) ; #f
(< 8 9) ; #t
(> 8 8) ; #f
(>= 8 8) ; #t
(define (goldilocks n smallest-ok biggest-ok)
(if (< n smallest-ok)
"That's too small!"
(if (> n biggest-ok)
"That's too big!"
"That's just right!")))
(goldilocks 7 6 8) ; "That's just right!"
(goldilocks 33 10 20) ; "That's too big!"
(goldilocks 3 10 20) ; "That's too small!"
(define (goldilocks n smallest-ok biggest-ok)
(cond ((< n smallest-ok) "That's too small!")
((> n biggest-ok) "That's too big!")
(else "That's just right!")))
(goldilocks 7 6 8) ; "That's just right!"
(goldilocks 33 10 20) ; "That's too big!"
(goldilocks 3 10 20) ; "That's too small!"
(member 'b '(a b c)) ; (b c)
(member 'z '(a b c)) ; #f
(define (fruit-sleuth fruit basket)
(if (member fruit basket)
"I found it!"
"Nope, not in here."))
(fruit-sleuth 'apple '(orange banana apple)) ; "I found it!"
(fruit-sleuth 'grape '(orange banana apple)) ; "Nope, not in here."

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7_list_and_cons.scm Normal file
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;; -*- geiser-scheme-implementation: guile -*-
(list 1 2 "cat" 33.8 'foo) ; (1 2 "cat" 33.8 foo)
'(1 2 "cat" 33.8 foo) ; (1 2 "cat" 33.8 foo)
(cons 'a '()) ; (a)
(cons 'a (cons 'b (cons 'c '()))) ; (a b c)
(list 'a 'b 'c) ; (a b c)
'(a b c) ; (a b c)
(car '(a b c)) ; a
(cdr '(a b c)) ; (b c)
(car (cdr '(a b c))) ; b
(cons 'a 'b) ; (a . b)
(+ 1 2 (- 8 4)) ; 7
'(+ 1 2 (- 8 4)) ; (+ 1 2 (- 8 4))
(let ((name "Horace"))
(string-append "Hello, " name)) ; "Hello, Horace"
'(let ((name "Horace"))
(string-append "Hello, " name)) ; (let ((name "Horace")) (string-append "Hello, " name))
'foo ; foo
(quote foo) ; foo
'(lambda (x) (* x 2)) ; (lambda (x) (* x 2))
(quote (lambda (x) (* x 2))) ; (lambda (x) (* x 2))
;;; assoc lists
(define animal-noises
'((cat . meow)
(dog . woof)
(pig . oink)))
(assoc 'cat animal-noises) ; (cat . meow)
(assoc 'alien animal-noises) ; #f
(define (cat-years years)
(cond
((<= years 1) ; first year equivalent to 15
(* years 15))
((<= years 2)
(+ 15 (* 9 (- years 1)))) ; second year 9
(else
(+ 24 (* 4 (- years 2)))))) ; years after that 4
(define (cat-entry name age)
`(cat (name ,name) (age ,age) (cat-years-age ,(cat-years age))))
(cat-entry "Missy Rose" 16) ; (cat (name "Missy Rose") (age 16) (cat-years-age 80))
(cat-entry "Kelsey" 22) ; (cat (name "Kelsey") (age 22) (cat-years-age 104))

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8_closures.scm Normal file
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;; -*- geiser-scheme-implementation: guile -*-
(define (make-goldilocks smallest-ok biggest-ok)
(define (goldilocks n)
(cond ((< n smallest-ok) 'too-small)
((> n biggest-ok) 'too-big)
(else 'just-right)))
goldilocks)
(make-goldilocks 10 30) ; #<procedure goldilocks (n)>
(define goldi (make-goldilocks 10 30)) ; #<unspecified>
(goldi 7) ; too-small
(goldi 256) ; too-big
(goldi 22) ; just-right
(define (abstract-cons car-data cdr-data)
(lambda (method)
(cond ((eq? method 'car) car-data)
((eq? method 'cdr) cdr-data)
(else (error "Unknown method -- ABSTRACT-CONS" method)))))
(define our-cons (abstract-cons 'foo 'bar))
(our-cons 'car) ; foo
(our-cons 'cdr) ; bar

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;; -*- geiser-scheme-implementation: guile -*-