Suggested changes to eventlog2html for proposed hvega 0.5 changes

gistfile1.txt

```
diff --git a/src/Eventlog/VegaTemplate.hs b/src/Eventlog/VegaTemplate.hs
index 773c916..eafafa6 100644
--- a/src/Eventlog/VegaTemplate.hs
+++ b/src/Eventlog/VegaTemplate.hs
@@ -18,8 +18,9 @@ import Data.Text.Lazy (toStrict)
 
 -- | Workaround for some limitations in the HVega library.
 -- This function should be removed once the features are merged into HVega.
-injectJSON :: Text -> Value -> BuildLabelledSpecs
-injectJSON t val = \x -> x ++ [(t,val)]
+injectJSON :: Text -> Value -> BuildSelectSpecs
+injectJSON t val = \x -> toSelectSpec t val : x
+
 
 data AreaChartType
   = Stacked
@@ -72,21 +73,21 @@ vegaResult conf = toVegaLite $
       AreaChart ct -> areaChartFull ct c'
   ]
 
-areaChartFull :: AreaChartType -> ChartConfig -> (VLProperty, VLSpec)
+areaChartFull :: AreaChartType -> ChartConfig -> PropertySpec
 areaChartFull ct c = hConcat
   [
     asSpec [vConcat [areaChart ct c, selectionChart c]]
   , legendDiagram
   ]
 
-lineChartFull :: ChartConfig -> (VLProperty, VLSpec)
+lineChartFull :: ChartConfig -> PropertySpec
 lineChartFull c = hConcat
   [
     asSpec [vConcat [lineChart c, selectionChart c]]
   , legendDiagram
   ]
 
-config :: [LabelledSpec] -> (VLProperty, VLSpec)
+config :: [ConfigureSpec] -> PropertySpec
 config =
   configure
     . configuration (TextStyle [(MAlign AlignRight), (MdX (-5)), (MdY 5)])
@@ -109,7 +110,7 @@ linesLayer c = asSpec
     transformLineLayer []
   ]
 
-encodingLineLayer :: ChartConfig -> [LabelledSpec] -> (VLProperty, VLSpec)
+encodingLineLayer :: ChartConfig -> [EncodingSpec] -> PropertySpec
 encodingLineLayer c
  = encoding
     . color [MName "c", MmType Nominal, MScale [colourProperty c], MLegend []]
@@ -117,7 +118,7 @@ encodingLineLayer c
                   PScale [SDomain (DSelection "brush")]]
     . position Y [PName "norm_y", PmType Quantitative, PAxis [AxTitle "Allocation", AxFormat ".1f"]]
 
-transformLineLayer :: [LabelledSpec] -> (VLProperty, VLSpec)
+transformLineLayer :: [TransformSpec] -> PropertySpec
 transformLineLayer =
   transform
   . window [([WField "y", WAggregateOp Max], "max_y")] [WFrame Nothing Nothing, WGroupBy ["k"]]
@@ -128,18 +129,22 @@ transformLineLayer =
 -- The Selection Chart
 -----------------------------------------------------------------------------------
 
-encodingSelection :: ChartConfig -> [LabelledSpec] -> (VLProperty, VLSpec)
+encodingSelection :: ChartConfig -> [EncodingSpec] -> PropertySpec
 encodingSelection c =
   encoding
     . order [OName "k", OmType Quantitative]
-    . injectJSON "tooltip" Null
+    . tooltip [] -- new in hvega 0.5.0.0 (although tooltips are also
+                 -- off by default in Vega-Lite 4)
     . color [MName "c", MmType Nominal, MScale [colourProperty c], MLegend []]
     . position X [PName "x", PmType Quantitative, PAxis [AxTitle "Time (s)"]]
     . position Y [PName "y", PmType Quantitative, PAxis [{-AxTitle "Allocation", AxFormat "s"-}], PAggregate Sum, PStack StZero]
 
-brush :: (VLProperty, VLSpec)
-brush = (selection . injectJSON "brush" (object [ "type" .= String "interval"
+brush :: PropertySpec
+brush = (selection .
+        {- Is this valid Vega-Lite? -}
+         injectJSON "brush" (object [ "type" .= String "interval"
                                                 , "init" .= object [ "x" .= [Null, Null] ] ])) []
+        
 -- init field is not supported and necessary for dynamic loading
 
 selectionChart :: ChartConfig -> VLSpec
@@ -178,8 +183,8 @@ bandsLayer ct c = asSpec
 
 encodingBandsLayer :: AreaChartType
                    -> ChartConfig
-                   -> [LabelledSpec]
-                   -> (VLProperty, VLSpec)
+                   -> [EncodingSpec]
+                   -> PropertySpec
 encodingBandsLayer ct c =
   encoding
     . order [OName "k", OmType Quantitative]
@@ -207,7 +212,7 @@ encodingBandsLayer ct c =
                  ++
                   [PScale [SDomain (DNumbers [0,  extent])] | Just extent <- [fixedYAxisExtent c]] )
 
-transformBandsLayer :: [LabelledSpec] -> (VLProperty, VLSpec)
+transformBandsLayer :: [TransformSpec] -> PropertySpec
 transformBandsLayer =
   transform
     . filter (FSelection "legend")
@@ -224,7 +229,7 @@ tracesLayer = asSpec
     encodingTracesLayer []
   ]
 
-encodingTracesLayer :: [LabelledSpec] -> (VLProperty, VLSpec)
+encodingTracesLayer :: [EncodingSpec] -> PropertySpec
 encodingTracesLayer =
   encoding
     . color [MString "grey"]
@@ -247,10 +252,10 @@ legendDiagram  = asSpec
     selectionRight []
   ]
 
-encodingRight :: [LabelledSpec] -> (VLProperty, VLSpec)
+encodingRight :: [EncodingSpec] -> PropertySpec
 encodingRight =
   encoding
-  . injectJSON "tooltip" Null
+  . tooltip []
   . color
      [
        MSelectionCondition (SelectionName "legend") [MName "c", MmType Nominal, MLegend []] [MString "lightgray"]
@@ -265,7 +270,7 @@ encodingRight =
                        , AxMaxExtent 100]
                , PSort [(ByFieldOp "k" Mean), Descending]]
 
-selectionRight :: [LabelledSpec] -> (VLProperty, VLSpec)
+selectionRight :: [SelectSpec] -> PropertySpec
 selectionRight =
     selection
      . select "legend" Multi [On "click", Encodings [ChColor], ResolveSelections Global, Toggle "event.shiftKey"]

```