implemented padNum

src/Mtlstats/Format.hs

@@ -0,0 +1,38 @@
+{- |
+
+mtlstats
+Copyright (C) 2019 Rhéal Lamothe
+<rheal.lamothe@gmail.com>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+-}
+
+module Mtlstats.Format (padNum) where
+
+-- | Pad an 'Int' with leading zeroes to fit a certain character width
+padNum
+  :: Int
+  -- ^ The width in characters
+  -> Int
+  -- ^ The value to format
+  -> String
+padNum size n
+  | n < 0 = '-' : padNum (pred size) (-n)
+  | otherwise = let
+    str  = show n
+    sLen = length str
+    pLen = size - sLen
+    pad  = replicate pLen '0'
+    in pad ++ str