Add FromValue and ToValue instances for UTCTime (#20)

ChangeLog.md

@@ -1,5 +1,10 @@
 # Revision history for toml-parser
 
+## 2.0.1.0
+
+* Added `ToValue UTCTime` and `FromValue UTCTime`. These correspond
+  to offset data-times with the timezone translated to UTC.
+
 ## 2.0.0.0
 
 * Pervasive annotations on the values added to allow for detailed

src/Toml/Schema/FromValue.hs

@@ -55,7 +55,7 @@ import Data.Sequence qualified as Seq
 import Data.Text (Text)
 import Data.Text qualified as Text
 import Data.Text.Lazy qualified
-import Data.Time (ZonedTime, LocalTime, Day, TimeOfDay)
+import Data.Time (ZonedTime, LocalTime, Day, TimeOfDay, UTCTime, zonedTimeToUTC)
 import Data.Word (Word8, Word16, Word32, Word64)
 import Numeric.Natural (Natural)
 import Toml.Schema.Matcher
@@ -245,6 +245,11 @@ instance FromValue ZonedTime where
     fromValue (ZonedTime' _ x) = pure x
     fromValue v = typeError "offset date-time" v
 
+-- | Matches offset date-time literals and converts to UTC
+instance FromValue UTCTime where
+    fromValue (ZonedTime' _ x) = pure (zonedTimeToUTC x)
+    fromValue v = typeError "offset date-time" v
+
 -- | Matches local date-time literals
 instance FromValue LocalTime where
     fromValue (LocalTime' _ x) = pure x

src/Toml/Schema/ToValue.hs

@@ -39,7 +39,7 @@ import Data.Sequence (Seq)
 import Data.Text (Text)
 import Data.Text qualified as Text
 import Data.Text.Lazy qualified
-import Data.Time (Day, TimeOfDay, LocalTime, ZonedTime)
+import Data.Time (Day, TimeOfDay, LocalTime, ZonedTime, UTCTime, utcToZonedTime, utc)
 import Data.Word (Word8, Word16, Word32, Word64)
 import Numeric.Natural (Natural)
 import Toml.Semantics
@@ -163,6 +163,7 @@ instance ToValue Bool      where toValue = Bool
 instance ToValue TimeOfDay where toValue = TimeOfDay
 instance ToValue LocalTime where toValue = LocalTime
 instance ToValue ZonedTime where toValue = ZonedTime
+instance ToValue UTCTime   where toValue = ZonedTime . utcToZonedTime utc
 instance ToValue Day       where toValue = Day
 instance ToValue Integer   where toValue = Integer
 instance ToValue Natural   where toValue = Integer . fromIntegral

test-drivers/toml-test-drivers.cabal

@@ -30,7 +30,7 @@ common shared
         ViewPatterns
     build-depends:
         base            ^>= {4.14, 4.15, 4.16, 4.17, 4.18, 4.19, 4.20},
-        toml-parser     ^>= 2.0.0.0,
+        toml-parser     ^>= 2.0.1.0,
 
 executable TomlDecoder
     import:             shared

toml-parser.cabal

@@ -1,6 +1,6 @@
 cabal-version:      3.0
 name:               toml-parser
-version:            2.0.0.0
+version:            2.0.1.0
 synopsis:           TOML 1.0.0 parser
 description:
     TOML parser using generated lexers and parsers with