Better diagnostics for unknown metrics

src/GEval/Common.hs

@@ -135,6 +135,7 @@ data GEvalException = NoExpectedFile FilePath
                       | UnexpectedMultipleOutputs
                       | OtherException String
                       | NoHeaderFile FilePath
+                      | UnknownMetric String
                       deriving (Eq)
 
 instance Exception GEvalException
@@ -157,6 +158,7 @@ instance Show GEvalException where
   show UnexpectedMultipleOutputs = "Multiple outputs are not possible in this mode, use -o option to select an output file"
   show (OtherException message) = message
   show (NoHeaderFile filePath) = somethingWrongWithFilesMessage "No file with header specification" filePath
+  show (UnknownMetric t) = "Unknown or broken metric definition: " ++ t
 
 somethingWrongWithFilesMessage :: String -> FilePath -> String
 somethingWrongWithFilesMessage msg filePath = Prelude.concat

src/GEval/Metric.hs

@@ -15,6 +15,7 @@ module GEval.Metric
 import Data.Word
 import Data.Text hiding (map)
 import Data.Monoid ((<>))
+import Control.Exception
 
 import GEval.Common
 import GEval.Clippings
@@ -192,7 +193,7 @@ instance Read Metric where
   readsPrec _ ('M':'u':'l':'t':'i':'L':'a':'b':'e':'l':'-':'L':'o':'g':'L':'o':'s':'s':theRest) = [(MultiLabelLogLoss, theRest)]
   readsPrec _ ('M':'u':'l':'t':'i':'L':'a':'b':'e':'l':'-':'L':'i':'k':'e':'l':'i':'h':'o':'o':'d':theRest) = [(MultiLabelLikelihood, theRest)]
   readsPrec _ ('H':'a':'v':'e':'r':'s':'i':'n':'e':theRest) = [(Haversine, theRest)]
-
+  readsPrec _ t = throw $ UnknownMetric t
 
 
 data MetricOrdering = TheLowerTheBetter | TheHigherTheBetter