diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## v0.2.0.0
+
+* Add getFieldOr [#10](https://github.com/brandonchinn178/toml-reader/issues/10)
+* Handle extremely large float values [#8](https://github.com/brandonchinn178/toml-reader/issues/8)
+* Add Exception instance for TOMLError
+
 ## v0.1.0.0
 
 Initial release
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -9,10 +9,14 @@
 ## Usage
 
 ```hs
+{-# LANGUAGE OverloadedStrings #-}
+
+import TOML (DecodeTOML, tomlDecoder, getField, decodeFile)
+
 data MyConfig = MyConfig
   { field1 :: Int
   , field2 :: Bool
-  }
+  } deriving (Show)
 
 instance DecodeTOML MyConfig where
   tomlDecoder =
diff --git a/src/TOML.hs b/src/TOML.hs
--- a/src/TOML.hs
+++ b/src/TOML.hs
@@ -8,6 +8,7 @@
 
   -- ** Decoding getters
   getField,
+  getFieldOr,
   getFields,
   getFieldOpt,
   getFieldsOpt,
diff --git a/src/TOML/Decode.hs b/src/TOML/Decode.hs
--- a/src/TOML/Decode.hs
+++ b/src/TOML/Decode.hs
@@ -20,6 +20,7 @@
 
   -- ** Decoder getters
   getField,
+  getFieldOr,
   getFields,
   getFieldOpt,
   getFieldsOpt,
@@ -57,6 +58,7 @@
 import qualified Data.List.NonEmpty as NonEmpty
 import Data.Map (Map)
 import qualified Data.Map.Strict as Map
+import Data.Maybe (fromMaybe)
 import qualified Data.Monoid as Monoid
 import Data.Proxy (Proxy (..))
 import Data.Ratio (Ratio)
@@ -278,6 +280,22 @@
 -}
 getField :: DecodeTOML a => Text -> Decoder a
 getField = getFieldWith tomlDecoder
+
+{- |
+Decode a field in a TOML Value or succeed with a default value when the field is missing.
+
+@
+a = 1
+# b is missing
+@
+
+@
+-- MyConfig 1 "asdf"
+MyConfig \<$> getFieldOr 42 "a" \<*> getFieldOr "asdf" "b"
+@
+-}
+getFieldOr :: DecodeTOML a => a -> Text -> Decoder a
+getFieldOr def key = fromMaybe def <$> getFieldOpt key
 
 -- | Same as 'getField', except with the given 'Decoder'.
 getFieldWith :: Decoder a -> Text -> Decoder a
diff --git a/src/TOML/Error.hs b/src/TOML/Error.hs
--- a/src/TOML/Error.hs
+++ b/src/TOML/Error.hs
@@ -11,6 +11,7 @@
   renderTOMLError,
 ) where
 
+import Control.Exception (Exception (..))
 import Data.List.NonEmpty (NonEmpty)
 import qualified Data.List.NonEmpty as NonEmpty
 import Data.Text (Text)
@@ -23,6 +24,9 @@
   | NormalizeError NormalizeError
   | DecodeError DecodeContext DecodeError
   deriving (Show, Eq)
+
+instance Exception TOMLError where
+  displayException = Text.unpack . renderTOMLError
 
 data NormalizeError
   = -- | When a key is defined twice, e.g.
diff --git a/src/TOML/Parser.hs b/src/TOML/Parser.hs
--- a/src/TOML/Parser.hs
+++ b/src/TOML/Parser.hs
@@ -382,7 +382,13 @@
           [ try $ (,) <$> pure "" <*> parseExp
           , (,) <$> parseFrac <*> optionalOr "" parseExp
           ]
-      pure $ readFloat $ intPart <> fracPart <> expPart
+
+      -- guess if the exponent is too big to fit in a double precision float anyway.
+      -- https://github.com/brandonchinn178/toml-reader/issues/8
+      pure $
+        if Text.length expPart > 7
+          then inf
+          else readFloat $ intPart <> fracPart <> expPart
 
     parseExp =
       fmap Text.concat . sequence $
diff --git a/src/TOML/Value.hs b/src/TOML/Value.hs
--- a/src/TOML/Value.hs
+++ b/src/TOML/Value.hs
@@ -1,5 +1,3 @@
-{-# LANGUAGE DeriveAnyClass #-}
-{-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE OverloadedStrings #-}
 
@@ -9,13 +7,11 @@
   Table,
 ) where
 
-import Control.DeepSeq (NFData)
 import Data.Map.Strict (Map)
 import qualified Data.Map.Strict as Map
 import Data.Text (Text)
 import qualified Data.Text as Text
 import Data.Time (Day, LocalTime, TimeOfDay, TimeZone)
-import GHC.Generics (Generic)
 
 type Table = Map Text Value
 
@@ -24,13 +20,13 @@
   | Array [Value]
   | String Text
   | Integer Integer
-  | Float Double
+  | Float Double -- TOML spec specifies this must be a double precision float: https://github.com/toml-lang/toml/issues/538
   | Boolean Bool
   | OffsetDateTime (LocalTime, TimeZone)
   | LocalDateTime LocalTime
   | LocalDate Day
   | LocalTime TimeOfDay
-  deriving (Show, Eq, Generic, NFData)
+  deriving (Show, Eq)
 
 -- | Render a Value in pseudo-JSON format.
 renderValue :: Value -> Text
diff --git a/test/tasty/Main.hs b/test/tasty/Main.hs
--- a/test/tasty/Main.hs
+++ b/test/tasty/Main.hs
@@ -2,6 +2,7 @@
 
 import qualified TOML.DecodeTest
 import qualified TOML.ErrorTest
+import qualified TOML.ParserTest
 import qualified TOML.Utils.MapTest
 import qualified TOML.Utils.NonEmptyTest
 
@@ -12,5 +13,6 @@
       [ TOML.Utils.MapTest.test
       , TOML.Utils.NonEmptyTest.test
       , TOML.ErrorTest.test
+      , TOML.ParserTest.test
       , TOML.DecodeTest.test
       ]
diff --git a/test/tasty/TOML/DecodeTest.hs b/test/tasty/TOML/DecodeTest.hs
--- a/test/tasty/TOML/DecodeTest.hs
+++ b/test/tasty/TOML/DecodeTest.hs
@@ -19,6 +19,7 @@
   getField,
   getFieldOpt,
   getFieldOptWith,
+  getFieldOr,
   getFieldWith,
   getFields,
   getFieldsOpt,
@@ -50,6 +51,15 @@
           decodeWith (getField @Int "a") "" @?= Left (DecodeError [Key "a"] MissingField)
       , testCase "errors if field is the wrong type" $
           decodeWith (getField @Int "a") "a = true" @?= Left (DecodeError [Key "a"] (TypeMismatch (Boolean True)))
+      ]
+  , testGroup
+      "getFieldOr"
+      [ testCase "decodes field" $
+          decodeWith (getFieldOr @Int 42 "a") "a = 1" @?= Right 1
+      , testCase "returns default if field does not exist" $
+          decodeWith (getFieldOr @Int 42 "a") "" @?= Right 42
+      , testCase "errors if field is the wrong type" $
+          decodeWith (getFieldOr @Int 42 "a") "a = true" @?= Left (DecodeError [Key "a"] (TypeMismatch (Boolean True)))
       ]
   , testGroup
       "getFieldOpt"
diff --git a/test/tasty/TOML/ParserTest.hs b/test/tasty/TOML/ParserTest.hs
new file mode 100644
--- /dev/null
+++ b/test/tasty/TOML/ParserTest.hs
@@ -0,0 +1,20 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module TOML.ParserTest (test) where
+
+import qualified Data.Map.Strict as Map
+import Test.Tasty (TestTree, testGroup)
+import Test.Tasty.HUnit
+
+import TOML.Parser (parseTOML)
+import TOML.Value (Value (..))
+
+test :: TestTree
+test =
+  testGroup
+    "TOML.Parser"
+    [ testCase "Large floats are parsed efficiently" $
+        case parseTOML "" "a = 1e1000000000000000000000000000000000000000000000000000000000000000" of
+          Right (Table t) -> Map.lookup "a" t @?= Just (Float (read "Infinity"))
+          result -> assertFailure $ "Got unexpected result: " ++ show result
+    ]
diff --git a/toml-reader.cabal b/toml-reader.cabal
--- a/toml-reader.cabal
+++ b/toml-reader.cabal
@@ -1,11 +1,11 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.34.4.
+-- This file has been generated from package.yaml by hpack version 0.35.0.
 --
 -- see: https://github.com/sol/hpack
 
 name:           toml-reader
-version:        0.1.0.0
+version:        0.2.0.0
 synopsis:       TOML format parser compliant with v1.0.0.
 description:    TOML format parser compliant with v1.0.0. See README.md for more details.
 category:       TOML, Text, Configuration
@@ -53,14 +53,13 @@
   build-depends:
       base >=4.9 && <5
     , containers >=0.6.0.1 && <0.7
-    , deepseq >=1.4.4.0 && <1.5
     , megaparsec >=7.0.5 && <9.3
     , parser-combinators >=1.1.0 && <1.4
-    , text >=1.2.3.1 && <1.3
-    , time >=1.8.0.2 && <1.12
+    , text >=1.2.3.1 && <2.1
+    , time >=1.8.0.2 && <1.13
+  default-language: Haskell2010
   if impl(ghc >= 8.0)
     ghc-options: -Wcompat -Wincomplete-record-updates -Wincomplete-uni-patterns -Wnoncanonical-monad-instances
-  default-language: Haskell2010
 
 test-suite parser-validator
   type: exitcode-stdio-1.0
@@ -82,9 +81,9 @@
     , toml-reader
     , unordered-containers
     , vector
+  default-language: Haskell2010
   if impl(ghc >= 8.0)
     ghc-options: -Wcompat -Wincomplete-record-updates -Wincomplete-uni-patterns -Wnoncanonical-monad-instances
-  default-language: Haskell2010
 
 test-suite toml-reader-tests
   type: exitcode-stdio-1.0
@@ -92,6 +91,7 @@
   other-modules:
       TOML.DecodeTest
       TOML.ErrorTest
+      TOML.ParserTest
       TOML.Utils.MapTest
       TOML.Utils.NonEmptyTest
       Paths_toml_reader
@@ -107,6 +107,6 @@
     , text
     , time
     , toml-reader
+  default-language: Haskell2010
   if impl(ghc >= 8.0)
     ghc-options: -Wcompat -Wincomplete-record-updates -Wincomplete-uni-patterns -Wnoncanonical-monad-instances
-  default-language: Haskell2010