Use the ReaderT to enable/disable debug printing

mengwong/mp/src/Lib.hs

@@ -35,7 +35,7 @@ import Debug.Trace
 
 import Types
 import Error
-import Control.Monad.Reader (ReaderT(runReaderT))
+import Control.Monad.Reader (ReaderT(runReaderT), asks)
 
 -- our task: to parse an input CSV into a collection of Rules.
 -- example "real-world" input can be found at https://docs.google.com/spreadsheets/d/1qMGwFhgPYLm-bmoN2es2orGkTaTN382pG2z3RjZ_s-4/edit
@@ -49,9 +49,17 @@ someFunc = do
 
 -- TODO: integrate debugging and callstack depth with the runConfig, thread it through all the functions here
 -- printf debugging infrastructure
-debuggery = False
-myTraceM x = when debuggery (traceM x)
-debugPrint depth str = when debuggery $ do
+
+whenDebug :: Parser () -> Parser ()
+whenDebug act = do
+  isDebug <- asks debug
+  when isDebug act
+
+myTraceM x = whenDebug (traceM x)
+
+debugPrint :: Int -> String -> ReaderT RunConfig (Parsec Void MyStream) ()
+
+debugPrint depth str = whenDebug $ do
   lookingAt <- lookAhead (getToken :: Parser MyToken)
   myTraceM $ indent <> str <> " running. depth=" <> show depth <> "; looking at: " <> show lookingAt
   where