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| author | Joe Zhao <ztuowen@gmail.com> | 2014-08-09 10:58:03 +0800 |
|---|---|---|
| committer | Joe Zhao <ztuowen@gmail.com> | 2014-08-09 10:58:03 +0800 |
| commit | 5bdaa1e4ffe40add10f000ee993e6b500c419a37 (patch) | |
| tree | 46a624488ece8d37fa3580422234ed2b4acc6728 /traffic.hs | |
| parent | 01aa73b269f7ad780233be338affdf3c9288b1ed (diff) | |
| download | haskbox-old-5bdaa1e4ffe40add10f000ee993e6b500c419a37.tar.gz haskbox-old-5bdaa1e4ffe40add10f000ee993e6b500c419a37.tar.bz2 haskbox-old-5bdaa1e4ffe40add10f000ee993e6b500c419a37.zip | |
add files from home for previous chapters and sandboxes
Diffstat (limited to 'traffic.hs')
| -rw-r--r-- | traffic.hs | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/traffic.hs b/traffic.hs new file mode 100644 index 0000000..f409de3 --- /dev/null +++ b/traffic.hs @@ -0,0 +1,14 @@ +data TrafficLight = Red | Yellow | Green + +instance Eq TrafficLight where + Red == Red = True + Yellow == Yellow = True + Green == Green = True + _ == _ = False + +instance Show TrafficLight where + show Red = "Red light" + show Yellow = "Yellow light" + show Green = "Green light" + +data Either a b = Left a | Right b |