Better Show instance for SourcePos/SourceSpan

hdgarrood · hdgarrood · commit 18bd86bcb9cc · 2015-04-07T21:20:25.000+01:00
Use the derived Show instance and define separate functions for
displaying SourcePos/SourceSpan values.
diff --git a/src/Language/PureScript/AST/SourcePos.hs b/src/Language/PureScript/AST/SourcePos.hs
@@ -30,10 +30,12 @@ data SourcePos = SourcePos
     -- Column number
     --
   , sourcePosColumn :: Int
-  } deriving (Eq, D.Data, D.Typeable)
+  } deriving (Eq, Show, D.Data, D.Typeable)
 
-instance Show SourcePos where
-  show sp = "line " ++ show (sourcePosLine sp) ++ ", column " ++ show (sourcePosColumn sp)
+displaySourcePos :: SourcePos -> String
+displaySourcePos sp =
+  "line " ++ show (sourcePosLine sp) ++
+    ", column " ++ show (sourcePosColumn sp)
 
 data SourceSpan = SourceSpan
   { -- |
@@ -47,7 +49,10 @@ data SourceSpan = SourceSpan
     -- End of the span
     --
   , spanEnd :: SourcePos
-  } deriving (Eq, D.Data, D.Typeable)
+  } deriving (Eq, Show, D.Data, D.Typeable)
 
-instance Show SourceSpan where
-  show sp = spanName sp ++ " " ++ show (spanStart sp) ++ " - " ++ show (spanEnd sp)
+displaySourceSpan :: SourceSpan -> String
+displaySourceSpan sp =
+  spanName sp ++ " " ++
+    displaySourcePos (spanStart sp) ++ " - " ++
+    displaySourcePos (spanEnd sp)
diff --git a/src/Language/PureScript/Errors.hs b/src/Language/PureScript/Errors.hs
@@ -439,7 +439,7 @@ prettyPrintSingleError full e = prettyPrintErrorMessage (if full then e else sim
     go (ErrorInForeignImport nm err)   = paras [ line $ "Error in foreign import " ++ show nm ++ ":"
                                                , go err
                                                ]
-    go (PositionedError pos err)       = paras [ line $ "Error at " ++ show pos ++ ":"
+    go (PositionedError span err)      = paras [ line $ "Error at " ++ displaySourceSpan span ++ ":"
                                                , indent $ go err
                                                ]
 

Original file line number	Diff line number	Diff line change
`@@ -439,7 +439,7 @@ prettyPrintSingleError full e = prettyPrintErrorMessage (if full then e else sim`
`439`	`439`	`go (ErrorInForeignImport nm err) = paras [ line $ "Error in foreign import " ++ show nm ++ ":"`
`440`	`440`	`, go err`
`441`	`441`	`]`
`442`		`- go (PositionedError pos err) = paras [ line $ "Error at " ++ show pos ++ ":"`
	`442`	`+ go (PositionedError span err) = paras [ line $ "Error at " ++ displaySourceSpan span ++ ":"`
`443`	`443`	`, indent $ go err`
`444`	`444`	`]`
`445`	`445`