Add helper functions for getting Reports & Markers out of Diagnostics

src/Error/Diagnose/Diagnostic.hs

@@ -23,8 +23,10 @@ import Error.Diagnose.Diagnostic.Internal as Export
     def,
     errorsToWarnings,
     hasReports,
+    reportsOf,
     prettyDiagnostic,
     printDiagnostic,
     warningsToErrors,
   )
+import Error.Diagnose.Report as Export (markersOf)
 import System.IO as Export (stderr, stdout)

src/Error/Diagnose/Diagnostic/Internal.hs

@@ -72,6 +72,10 @@ hasReports :: Diagnostic msg -> Bool
 hasReports (Diagnostic DL.Nil _) = False
 hasReports _ = True
 
+-- | Retrieves the reports for this diagnostic.
+reportsOf :: Diagnostic msg -> [Report msg]
+reportsOf (Diagnostic reports _) = toList reports
+
 -- | Transforms every warning report in this diagnostic into an error report.
 warningsToErrors :: Diagnostic msg -> Diagnostic msg
 warningsToErrors (Diagnostic reports files) = Diagnostic (warningToError <$> reports) files

src/Error/Diagnose/Report.hs

@@ -11,4 +11,4 @@ module Error.Diagnose.Report
   )
 where
 
-import Error.Diagnose.Report.Internal as Export (Marker (..), Note (..), Report, err, errorToWarning, warn, warningToError)
+import Error.Diagnose.Report.Internal as Export (Marker (..), Note (..), Report, err, errorToWarning, warn, warningToError, markersOf)

src/Error/Diagnose/Report/Internal.hs

@@ -95,6 +95,11 @@ instance ToJSON msg => ToJSON (Report msg) where
                               ]
 #endif
 
+-- | Retrieves the markers for this reports, along with their corresponding
+--   positions in the source code.
+markersOf :: Report msg -> [(Position, Marker msg)]
+markersOf (Report _ _ _ markers _) = markers
+
 -- | The type of markers with abstract message type, shown under code lines.
 data Marker msg
   = -- | A red or yellow marker under source code, marking important parts of the code.