implemented left

src/Mtlstats/Format.hs

@@ -19,7 +19,10 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 -}
 
-module Mtlstats.Format (padNum) where
+module Mtlstats.Format
+  ( padNum
+  , left
+  ) where
 
 -- | Pad an 'Int' with leading zeroes to fit a certain character width
 padNum
@@ -36,3 +39,12 @@ padNum size n
     pLen = size - sLen
     pad  = replicate pLen '0'
     in pad ++ str
+
+-- | Aligns text to the left within a field (clipping if necessary)
+left
+  :: Int
+  -- ^ The width of the field
+  -> String
+  -- ^ The text to align
+  -> String
+left n str = take n $ str ++ repeat ' '

test/FormatSpec.hs

@@ -26,8 +26,9 @@ import Test.Hspec (Spec, context, describe, it, shouldBe)
 import Mtlstats.Format
 
 spec :: Spec
-spec = describe "Mtlstats.Format"
+spec = describe "Mtlstats.Format" $ do
   padNumSpec
+  leftSpec
 
 padNumSpec :: Spec
 padNumSpec = describe "padNum" $ do
@@ -51,3 +52,14 @@ padNumSpec = describe "padNum" $ do
   context "-1234, four digits" $
     it "should be -1234" $
       padNum 4 (-1234) `shouldBe` "-1234"
+
+leftSpec :: Spec
+leftSpec = describe "left" $ do
+
+  context "fit" $
+    it "should pad the text" $
+      left 5 "foo" `shouldBe` "foo  "
+
+  context "overflow" $
+    it "should truncate the text" $
+      left 2 "foo" `shouldBe` "fo"