Add test case for lexer issue and fix other instance.

src/Libraries/Text/Lexer/Core.idr

@@ -155,7 +155,7 @@ tokenise pred line col acc tmap str
 
     getCols : List Char -> Int -> Int
     getCols x c
-         = case span (/= '\n') (reverse x) of
+         = case span (/= '\n') x of
                 (incol, []) => c + cast (length incol)
                 (incol, _) => cast (length incol)
 

tests/contrib/lexer/Test.idr

@@ -0,0 +1,23 @@
+import Text.Lexer
+
+data Kind = Ignore | Ident | Oper | Number
+
+ignore : WithBounds (Token Kind) -> Bool
+ignore (MkBounded (Tok Ignore _) _ _) = True
+ignore _ = False
+
+tmap : TokenMap (Token Kind)
+tmap = [
+  (alpha <+> many alphaNum, Tok Ident),
+  (some digit, Tok Number),
+  (some symbol, Tok Oper),
+  (spaces, Tok Ignore)
+]
+
+show : WithBounds (Token Kind) -> String
+show t@(MkBounded (Tok _ v) _ _) = "\{show $ start t} \{show v}"
+
+main : IO ()
+main = do
+  let toks = filter (not . ignore) $ fst $ lex tmap  "let x = 1\n    y = 2\n in x + y"
+  traverse_ (putStrLn . show) toks

tests/contrib/lexer/expected

@@ -0,0 +1,11 @@
+(0, 0) "let"
+(0, 4) "x"
+(0, 6) "="
+(0, 8) "1"
+(1, 4) "y"
+(1, 6) "="
+(1, 8) "2"
+(2, 1) "in"
+(2, 4) "x"
+(2, 6) "+"
+(2, 8) "y"

tests/contrib/lexer/run

@@ -0,0 +1,3 @@
+$1 --no-banner --no-color --console-width 0 -p contrib -x main Test.idr
+
+rm -rf build