Add output of a few front page examples in explanations.

This commit is contained in:
Sam Tobin-Hochstadt 2014-04-07 15:46:51 -04:00
parent c90538d249
commit a5bc367b89
3 changed files with 14 additions and 5 deletions

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@ -114,11 +114,13 @@
[(zero? n) (triangle 2 'solid 'red)] [(zero? n) (triangle 2 'solid 'red)]
[else (define t (sierpinski (- n 1))) [else (define t (sierpinski (- n 1)))
(freeze (above t (beside t t)))]))} (freeze (above t (beside t t)))]))}
(list
@desc{The @elemcode{2htdp/image} library provides easy-to-use functions @desc{The @elemcode{2htdp/image} library provides easy-to-use functions
for constructing images, and DrRacket can display an image result as for constructing images, and DrRacket can display an image result as
easily as it can display a number result. In this case, a easily as it can display a number result. In this case, a
@elemcode{sierpinski} function is defined and called (at the same time) @elemcode{sierpinski} function is defined and called (at the same time)
to generate a Sierpinski triangle of depth 8.}) to generate a Sierpinski triangle of depth 8. It looks like}
@img[width: "50%" src: (copyfile #:site www-site (build-path img-dir "sierp.png"))]))
(graphical-example #:title "GUI Programming"; --------------------------------------------- (graphical-example #:title "GUI Programming"; ---------------------------------------------
@code{#lang racket/gui ; A GUI guessing game @code{#lang racket/gui ; A GUI guessing game
(define f (new frame% [label "Guess"])) (define f (new frame% [label "Guess"]))
@ -158,14 +160,19 @@
@code{#lang racket @code{#lang racket
;; Print the Greek alphabet ;; Print the Greek alphabet
(for ([i (in-range 25)]) (for ([i (in-range 25)])
(displayln (display
(integer->char (integer->char
(+ i (char->integer #\α)))))} (+ i (char->integer #\α)))))}
(list
@span{This prints out: }
@|br|
@elemcode{αβγδεζηθικλμνξοπρςστυφχψω}
@|br|
@desc{You can also spell @elemcode{#\α} as @desc{You can also spell @elemcode{#\α} as
@elemcode{#\u3B1} to stay within ASCII. @elemcode{#\u3B1} to stay within ASCII.
Fortunately, Racket and DrRacket are both Fortunately, Racket and DrRacket are both
perfectly happy to use Unicode characters, and DrRacket comes perfectly happy to use Unicode characters, and DrRacket comes
with shortcuts for inserting them.}) with shortcuts for inserting them.}))
(graphical-example #:title "Functional Animations"; --------------------------------------------- (graphical-example #:title "Functional Animations"; ---------------------------------------------
@code{#lang htdp/bsl ; Any key inflates the balloon @code{#lang htdp/bsl ; Any key inflates the balloon
(require 2htdp/image) (require 2htdp/universe) (require 2htdp/image) (require 2htdp/universe)
@ -218,9 +225,11 @@
(define (thrice f) (lambda (x) (f (f (f x))))) (define (thrice f) (lambda (x) (f (f (f x)))))
(plot (list (function ((thrice deriv) sin) -5 5) (plot (list (function ((thrice deriv) sin) -5 5)
(function cos -5 5 #:color 'blue)))} (function cos -5 5 #:color 'blue)))}
(list
@desc{This program uses the @elemcode{plot} library to draw plots of @desc{This program uses the @elemcode{plot} library to draw plots of
functions. Note that the plots are actual value, which DrRacket shows functions. Note that the plots are actual values, which DrRacket shows
in graphical form.}) in graphical form. It looks like}
@img[width: "50%" src: (copyfile #:site www-site (build-path img-dir "cos-deriv.png"))]))
(generic-example #:title "Sending email"; ----------------------------------------------- (generic-example #:title "Sending email"; -----------------------------------------------
@code{#lang racket ; Sending email from racket @code{#lang racket ; Sending email from racket
(require net/sendmail) (require net/sendmail)