Add version and help options to linkwave

src/linkwave.scm

@@ -26,6 +26,8 @@
 (require-extension sqlite3)
 (require-library posix srfi-4)
 
+(define version "0.1.0")
+
 (: string-no-null (string -> string))
 (define (string-no-null str)
   ;; If STR contains a \0 byte at the end, remove it, otherwise return
@@ -74,19 +76,45 @@
        (or (string= (substring str 0 7) "http://")
            (string= (substring str 0 8) "https://"))))
 
+(define (display-version)
+  ;; Display linkwave's version number.
+  (format #t "linkwave v~a~%" version))
+
+(define (display-help)
+  ;; Display linkwave's help message.
+  (format #t (string-append
+              "Usage: linkwave [options]...~%"
+              "       linkwave <url> <name> <description> [<tag>...]~%"
+              "~%"
+              "Possible options:~%"
+              "~%"
+              "--help, -h     Display this help and exit~%"
+              "--version, -v  Output version information and exit~%")))
+
 (define (main args)
   ;; Open a database connection, do what the user asked and close it
   ;; again.
   (let ((db (open-database (data-file "linkwave.db"))))
     (if (null? args)
         (for-each-row print-row db "select * from bookmark")
-        (cond
-         ((url-string? (car args))
-          (with-transaction
-           db (lambda () (add-bookmark db (car args) (cadr args) (caddr args) (cdddr args)) #t)))
-         (else
-          (format #t "Unrecognized option: ~a~%" (car args)))))
-
+        (if (url-string? (car args))
+            (with-transaction
+             db (lambda () (add-bookmark db (car args) (cadr args) (caddr args) (cdddr args)) #t))
+            ;; If the first argument is not a URL, loop through all
+            ;; arguments and proceed accordingly.
+            (do ((arg (car args) (and (not (null? args))
+                                      (car args))))
+                ((or (null? arg) (not arg)))
+              (cond
+               ((or (string= arg "-v") (string= arg "--version"))
+                (display-version)
+                (exit 0))
+               ((or (string= arg "-h") (string= arg "--help"))
+                (display-help)
+                (exit 0))
+               (else
+                (format #t "Unrecognized option: ~a~%" (car args))))
+              (set! args (cdr args)))))
     (finalize! db #t)))
 
 (main (command-line-arguments))