#lang racket/base (require racket/file racket/list racket/match racket/string) ;; ------------------------------------------------ ;; Constants ;; ------------------------------------------------ (define help-command-1 "help") (define help-command-2 "--help") (define help-command-3 "-h") (define init-command "init") (define ls-command "ls") (define rm-command "rm") (define add-command "add") (define program-name "nicethings") (define program-file (string-append "." program-name)) (define program-path (build-path (find-system-path 'home-dir) program-file)) (define program-permissions 420) ;; 644/-rw-r--r-- permissions (define newline "\n") (define double-newline "\n\n") ;; ------------------------------------------------ ;; Messages ;; ------------------------------------------------ (define messages (hash 'error-too-many-arguments (format (string-append "Error: Too many arguments." newline "Try running '~a ~a' for more information.") program-name help-command-1) 'error-incorrect-usage (format (string-append "Error: Incorrect usage." newline "Try running '~a ~a' for more information.") program-name help-command-1) 'error-file-already-exists (format "Error: The file '~a' already exists." program-path) 'error-fake-file-exists (format (string-append "Error: The directory '~a' exists." newline "Try moving, renaming, or deleting this directory.") program-path) 'error-file-doesnt-exist (format (string-append "Error: '~a' doesn't exist." newline "Try running '~a ~a'.") program-path program-name init-command) 'error-item-not-found "Error: Item not found." 'warning-permissions (format (string-append "Warning: The permissions on your '~a' file are incorrect." newline "Other users on this host may be able to read your file." newline "Try running 'chmod 600 ~a' to fix this." newline) program-path program-path) 'init-cancelled (format "Cancelled the creation of '~a'." program-path) 'init-prompt (format (string-append "~a will create '~a'." newline "Is this okay? [y/n]") program-name program-path) 'file-created (format "Successfully created ~a." program-path) 'empty-list "There is nothing in your list.")) (define formatees (hash 'error-not-an-option (string-append "Error: '~a' is not an option." newline "Please choose 'y' or 'n'.") 'error-not-a-number (string-append "Error: '~a' is not a number.") 'added "Added '~a' to your list." 'removed "Removed '~a' from your list.")) ;; ------------------------------------------------ ;; helpers ;; ------------------------------------------------ (define (messages-ref key) (hash-ref messages key)) (define (formatees-ref key) (hash-ref formatees key)) (define (displayln-messages-ref key) (let ([message (messages-ref key)]) (displayln message))) (define (displayln-formatees-ref key string) (let* ([formatee (formatees-ref key)] [formatee-formatted (format formatee string)]) (displayln formatee-formatted))) (define (create-file string) (close-output-port (open-output-file string))) (define (has-program-permissions? string) (equal? program-permissions (file-or-directory-permissions string 'bits))) ;; ------------------------------------------------ ;; Check conditions ;; ------------------------------------------------ (define (check-conditions) (cond [(directory-exists? program-path) (begin (displayln-messages-ref 'error-fake-file-exists) (exit))] [(not (file-exists? program-path)) (begin (displayln-messages-ref 'error-file-doesnt-exist) (exit))] [(not (has-program-permissions? program-path)) (displayln-messages-ref 'warning-permissions)] [else 'do-nothing])) ;; ------------------------------------------------ ;; init ;; ------------------------------------------------ (define (init/create-file) (create-file program-path) (file-or-directory-permissions program-path program-permissions) (displayln-messages-ref 'file-created)) (define (init/cancel) (displayln-messages-ref 'init-cancelled) (exit)) (define (init/prompt) (displayln-messages-ref 'init-prompt) (display "> ") (let* ([input (read-line)] [input-symbol (string->symbol input)]) (case input-symbol ['y (init/create-file)] ['n (init/cancel)] [else (displayln-formatees-ref 'error-not-an-option input)]))) (define (init) (cond [(file-exists? program-path) (displayln-messages-ref 'error-file-already-exists)] [(directory-exists? program-path) (displayln-messages-ref 'error-fake-file-exists)] [else (init/prompt)])) ;; ------------------------------------------------ ;; ls ;; ------------------------------------------------ (define (ls/display-list listof-items) ;; The add1 in the first binding starts the ;; listof-numbers at 1 instead of 0 to make the ;; list numbering more human-friendly (let* ([listof-numbers (map add1 (range (length listof-items)))] [listof-number-strings (map number->string listof-numbers)] [combine-lists (lambda (a b) (string-append a ". " b))] [listof-numbered-items (map combine-lists listof-number-strings listof-items)]) (for ([item listof-numbered-items]) (displayln item)))) (define (ls) (check-conditions) (let ([listof-items (file->lines program-path)]) (if (null? listof-items) (displayln-messages-ref 'empty-list) (ls/display-list listof-items)))) ;; ------------------------------------------------ ;; rm ;; ------------------------------------------------ (define (rm/remove-item listof-items item-number) (let* ([item-to-remove (list-ref listof-items item-number)] [list-without-item (remove item-to-remove listof-items)]) (display-lines-to-file list-without-item program-path #:exists 'truncate) (displayln-formatees-ref 'removed item-to-remove))) (define (rm/process-string string) (let* ([listof-items (file->lines program-path)] [item-number (string->number string)] ;; Subtract 1 from the user's original number, ;; because we want to convert the number from ;; human numbers (1 2 3) to index numbers ;; (0 1 2) [item-number-sub1 (sub1 item-number)] [list-length (length listof-items)]) (if (and (not (null? listof-items)) (number? item-number) (positive? item-number) ;; Don't allow numbers that are equal to ;; or greater than list-length, because ;; the list index starts at 0 ;; ;; Example: ;; Length of (1 2 3) = 3 ;; ;; To reference the highest number, we ;; use (list-ref (1 2 3) 2) (< item-number-sub1 list-length)) (rm/remove-item listof-items item-number-sub1) (displayln-messages-ref 'error-item-not-found)))) (define (rm string) (check-conditions) (if (string->number string) (rm/process-string string) (displayln-formatees-ref 'error-not-a-number string))) ;; ------------------------------------------------ ;; add ;; ------------------------------------------------ (define (add string) (check-conditions) ;; The removing and adding of the '\n' is to ;; ensure only one '\n' exists at the end of the ;; item to be added. (let* ([string-no-newline (string-replace string "\n" "")] [string-newline (string-append string-no-newline "\n")]) (display-to-file string-newline program-path #:exists 'append) (displayln-formatees-ref 'added string-no-newline))) ;; ------------------------------------------------ ;; random message ;; ------------------------------------------------ (define (random-message/append-program-file home-directory) (build-path home-directory program-file)) (define (random-message) (let* ([root (find-system-path 'sys-dir)] ;; / [root-home (build-path root "home")] ;; /home ;; `#:build? #t` Builds full paths for all items listed in /home/ [listof-home-directories (directory-list root-home #:build? #t)] [listof-nicethings-paths (map random-message/append-program-file listof-home-directories)] [directories-with-nicethings (filter file-exists? listof-nicethings-paths)] [directories-with-644 (filter has-program-permissions? directories-with-nicethings)] [listof-nicethings (apply append (map file->lines directories-with-644))] [list-length (length listof-nicethings)]) (when (not (zero? list-length)) (let* ([random-number (random list-length)] [random-nicething (list-ref listof-nicethings random-number)]) (displayln random-nicething))))) ;; ------------------------------------------------ ;; help ;; ------------------------------------------------ (define (help) (displayln (string-append "Usage:" newline (format " ~a [] []" program-name) double-newline "Commands:" newline " No command - Displays a random nicething from a random user." newline (format " ~a - Creates a file in ~a, which allows you to contribute to the town-wide list of nicethings." init-command program-path) newline (format " ~a - Adds a nicething to your list." add-command) newline (format " ~a - Prints a numbered list of the nicethings you've added." ls-command) newline (format " ~a - Removes a nicething from your list." rm-command) double-newline "Examples:" newline (format " ~a" program-name) newline (format " ~a ~a" program-name init-command) newline (format " ~a ~a \"You are wonderful\"" program-name add-command) newline (format " ~a ~a" program-name ls-command) newline (format " ~a ~a 2" program-name rm-command)))) (define (process-args vectorof-args) (match vectorof-args [(or (vector (== help-command-1)) (vector (== help-command-2)) (vector (== help-command-3))) (help)] [(vector (== ls-command)) (ls)] [(vector (== init-command)) (init)] [(vector (== add-command) a) (add a)] [(vector (== rm-command) a) (rm a)] [(vector _ _ _ ...) (displayln-messages-ref 'error-too-many-arguments)] [(vector _ _) (displayln-messages-ref 'error-incorrect-usage)] [(vector _) (displayln-messages-ref 'error-incorrect-usage)] [_ (random-message)])) (define (main vectorof-args) (process-args vectorof-args)) (main (current-command-line-arguments))