cli: Add --version flag.

* sly/config.scm.in (%sly-version): New variable.

2 files changed, 18 insertions, 0 deletions

diff --git a/sly/cli.scm b/sly/cli.scm
index b4040d0..49b5070 100644
--- a/sly/cli.scm
+++ b/sly/cli.scm
@@ -19,6 +19,7 @@
   #:use-module (ice-9 format)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-37)
+  #:use-module (sly config)
   #:use-module (sly game)
   #:use-module (sly input keyboard)
   #:use-module (sly repl)
@@ -77,6 +78,10 @@
                 (lambda _
                   (show-help)
                   (exit 0)))
+        (option '(#\V "version") #f #f
+                (lambda _
+                  (show-version)
+                  (exit 0)))
         (option '(#\d "develop") #f #f
                 (lambda (opt name arg result)
                   (alist-cons 'develop? #t result)))))
@@ -85,9 +90,19 @@
   (display "Usage: sly [OPTION]... GAME-DIRECTORY
 Run the Sly game located in GAME-DIRECTORY.\n")
   (display "
+  -v, --version          Display version information")
+  (display "
   -d, --develop          Run in development mode")
   (newline))
 
+(define (show-version)
+  (format #t "sly ~a~%" %sly-version)
+  (display "Copyright (C) 2016 the Sly authors
+License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.")
+  (newline))
+
 (define (sly-main args)
   (let* ((opts (args-fold args
                           %options
diff --git a/sly/config.scm.in b/sly/config.scm.in
index 46f8bfe..cd70d63 100644
--- a/sly/config.scm.in
+++ b/sly/config.scm.in
@@ -23,11 +23,14 @@
 
 (define-module (sly config)
   #:export (%datadir
+            %sly-version
             scope-datadir))
 
 (define %datadir
   (or (getenv "SLY_DATADIR") "@sly_datadir@/sly"))
 
+(define %sly-version "@PACKAGE_VERSION@")
+
 (define (scope-datadir file)
   "Append the Sly data directory to FILE."
   (string-append %datadir file))