diff --git a/src/KDL/Decoder/Arrow.hs b/src/KDL/Decoder/Arrow.hs
index c5bf769..6479c35 100644
--- a/src/KDL/Decoder/Arrow.hs
+++ b/src/KDL/Decoder/Arrow.hs
@@ -128,6 +128,7 @@ import KDL.Types (
   NodeList (..),
   Value (..),
   ValueData (..),
+  def,
  )
 import Numeric.Natural (Natural)
 import Prelude hiding (any, fail, null)
@@ -627,7 +628,7 @@ instance DecodeNode Node where
         , name = name
         , entries = []
         , children = Nothing
-        , format = Nothing
+        , ext = def
         }
 
 -- | Decode an argument in the node.
@@ -849,7 +850,7 @@ children decoder =
         }
     pure b
  where
-  emptyNodeList = NodeList{nodes = [], format = Nothing}
+  emptyNodeList = NodeList{nodes = [], ext = def}
 
 {----- Decoding ValueData -----}
 
diff --git a/src/KDL/Parser.hs b/src/KDL/Parser.hs
index b830e0d..cfed145 100644
--- a/src/KDL/Parser.hs
+++ b/src/KDL/Parser.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE OverloadedRecordDot #-}
 {-# LANGUAGE OverloadedStrings #-}
 
 {-|
@@ -6,23 +7,38 @@ Implement the v2 parser specified at: https://kdl.dev/spec/#name-full-grammar
 module KDL.Parser (
   parse,
   parseFile,
+
+  -- * Configurable parsing
+  ParseConfig (..),
+  parseWith,
+  parseFileWith,
 ) where
 
 import Data.Bifunctor (first)
+import Data.Default (def)
 import Data.Text (Text)
 import Data.Text qualified as Text
 import Data.Text.IO qualified as Text
-import KDL.Parser.Internal (p_document)
+import KDL.Parser.Internal (
+  ParseConfig (..),
+  p_document,
+  runParser,
+ )
 import KDL.Types (Document)
 import Text.Megaparsec qualified as Megaparsec
 
 parse :: Text -> Either Text Document
-parse = parse' ""
+parse = parseWith def
+
+parseFile :: FilePath -> IO (Either Text Document)
+parseFile = parseFileWith def
 
-parse' :: FilePath -> Text -> Either Text Document
-parse' fp input =
+parseWith :: ParseConfig -> Text -> Either Text Document
+parseWith config input =
   first (Text.strip . Text.pack . Megaparsec.errorBundlePretty) $
-    Megaparsec.parse p_document fp input
+    runParser config p_document input
 
-parseFile :: FilePath -> IO (Either Text Document)
-parseFile fp = parse' fp <$> Text.readFile fp
+parseFileWith :: ParseConfig -> FilePath -> IO (Either Text Document)
+parseFileWith config0 fp = parseWith config <$> Text.readFile fp
+ where
+  config = config0{filepath = fp}
diff --git a/src/KDL/Parser/Internal.hs b/src/KDL/Parser/Internal.hs
index 8648861..8a093fe 100644
--- a/src/KDL/Parser/Internal.hs
+++ b/src/KDL/Parser/Internal.hs
@@ -11,6 +11,8 @@ Implement the v2 parser specified at: https://kdl.dev/spec/#name-full-grammar
 -}
 module KDL.Parser.Internal (
   Parser,
+  ParseConfig (..),
+  runParser,
 
   -- * (1) Compatibility
   p_bom,
@@ -112,6 +114,8 @@ module KDL.Parser.Internal (
 ) where
 
 import Control.Monad (guard, void, (>=>))
+import Control.Monad.Trans.Class qualified as Trans
+import Control.Monad.Trans.Reader qualified as Reader
 import Control.Monad.Trans.State.Strict (StateT, evalStateT)
 import Control.Monad.Trans.State.Strict qualified as State
 import Data.Bifunctor (bimap)
@@ -125,9 +129,11 @@ import Data.Char (
   isSpace,
   ord,
  )
+import Data.Default (Default (..))
 import Data.Either (isRight)
 import Data.Foldable (foldlM, traverse_)
 import Data.Foldable qualified as Seq (toList)
+import Data.List.NonEmpty qualified as NonEmpty
 import Data.Maybe (catMaybes, fromMaybe, isJust)
 import Data.Scientific (Scientific)
 import Data.Scientific qualified as Scientific
@@ -139,32 +145,60 @@ import Data.Text qualified as Text
 import Data.Void (Void)
 import KDL.Types (
   Ann (..),
+  AnnExtension (..),
   AnnFormat (..),
   Document,
   Entry (..),
+  EntryExtension (..),
   EntryFormat (..),
   Identifier (..),
+  IdentifierExtension (..),
   IdentifierFormat (..),
   Node (..),
+  NodeExtension (..),
   NodeFormat (..),
   NodeList (..),
+  NodeListExtension (..),
   NodeListFormat (..),
+  Span (..),
   Value (..),
   ValueData (..),
+  ValueExtension (..),
   ValueFormat (..),
  )
+import KDL.Types qualified as AnnExtension (AnnExtension (..))
 import KDL.Types qualified as AnnFormat (AnnFormat (..))
+import KDL.Types qualified as EntryExtension (EntryExtension (..))
 import KDL.Types qualified as EntryFormat (EntryFormat (..))
+import KDL.Types qualified as Node (Node (..))
+import KDL.Types qualified as NodeExtension (NodeExtension (..))
 import KDL.Types qualified as NodeFormat (NodeFormat (..))
+import KDL.Types qualified as NodeListExtension (NodeListExtension (..))
 import KDL.Types qualified as NodeListFormat (NodeListFormat (..))
-import Text.Megaparsec
+import Text.Megaparsec hiding (runParser)
 import Text.Megaparsec.Char
+import Prelude hiding (span)
 
 #if !MIN_VERSION_base(4,20,0)
 import Data.Foldable (foldl')
 #endif
 
-type Parser = Parsec Void Text
+data ParseConfig = ParseConfig
+  { filepath :: FilePath
+  , includeSpans :: Bool
+  }
+
+instance Default ParseConfig where
+  def =
+    ParseConfig
+      { filepath = ""
+      , includeSpans = False
+      }
+
+type Parser = ParsecT Void Text (Reader.Reader ParseConfig)
+
+runParser :: ParseConfig -> Parser a -> Text -> Either (ParseErrorBundle Text Void) a
+runParser config p = (`Reader.runReader` config) . runParserT p config.filepath
 
 {----- (1) Compatibility -----}
 
@@ -208,7 +242,7 @@ p_nodes = label "nodes" $ do
   -- The grammar is left-associative, but we do right-associative to get
   -- correct backtracking semantics + good parse errors
   initialWS <- withSource_ $ many p_line_space
-  results <- fmap concat . manyWhile $ do
+  (results, span) <- withSpan . fmap concat . manyWhile $ do
     (sdash, parseNode) <- p_node
     (result, continue) <-
       resolveSlashdash sdash parseNode >>= \case
@@ -224,7 +258,12 @@ p_nodes = label "nodes" $ do
         if null nodes
           then (leftoverWS, "")
           else ("", leftoverWS)
-  pure NodeList{format = Just NodeListFormat{..}, ..}
+      ext =
+        NodeListExtension
+          { format = Just NodeListFormat{..}
+          , span
+          }
+  pure NodeList{..}
  where
   manyWhile :: Parser (a, Bool) -> Parser [a]
   manyWhile p =
@@ -263,9 +302,22 @@ p_node :: Parser (SlashdashResult, Parser (Node, Bool))
 p_node = label "node" $ do
   (sdash, parseNode) <- p_base_node
   pure . (sdash,) $ do
+    spanStart <- startSpan
     node <- parseNode
     mTerminator <- optional p_node_terminator
-    pure (mapFormat (maybe id setTerminator mTerminator) node, isJust mTerminator)
+    span <- finishSpan spanStart
+    let node' =
+          case mTerminator of
+            Just terminator ->
+              node
+                { Node.ext =
+                    node.ext
+                      { NodeExtension.format = setTerminator terminator <$> node.ext.format
+                      , NodeExtension.span = span
+                      }
+                }
+            Nothing -> node
+    pure (node', isJust mTerminator)
  where
   setTerminator terminator format =
     format
@@ -286,6 +338,8 @@ p_base_node :: Parser (SlashdashResult, Parser Node)
 p_base_node = label "base node" $ do
   sdash <- option NoSlashdash p_slashdash
   pure . (sdash,) $ do
+    spanStart <- startSpan
+
     -- node ann
     initialAnn <- optional p_type
     postAnnWS <- withSource_ $ many p_node_space
@@ -314,6 +368,8 @@ p_base_node = label "base node" $ do
         <*> p_node_children
     let beforeChildren = postEntriesWS <> slashdashedChildren1 <> fromMaybe "" preChildrenWS
 
+    span <- finishSpan spanStart
+
     -- slashdashed node-children #2
     slashdashedChildren2 <- p_slashdashed_children
 
@@ -325,7 +381,13 @@ p_base_node = label "base node" $ do
     let beforeTerminator = ""
         terminator = ""
 
-    pure Node{format = Just NodeFormat{..}, ..}
+    let ext =
+          NodeExtension
+            { format = Just NodeFormat{..}
+            , span
+            }
+
+    pure Node{..}
  where
   -- (node-space* (node-space | slashdash) node-prop-or-arg)*
   p_entries = fmap concat . many . label "node prop or arg" $ do
@@ -387,11 +449,13 @@ p_escline = label "escline" $ do
 -- prop := string node-space* '=' node-space* value
 p_prop :: Parser Entry
 p_prop = label "property" $ do
+  spanStart <- startSpan
   name <- p_string'Identifier
   afterKey <- withSource_ $ many p_node_space
   _ <- char '='
   afterEq <- withSource_ $ many p_node_space
   (value, leading) <- p_value
+  span <- finishSpan spanStart
   let format =
         EntryFormat
           { leading
@@ -399,14 +463,15 @@ p_prop = label "property" $ do
           , afterEq
           , trailing = ""
           }
-  pure Entry{name = Just name, value, format = Just format}
+      ext = EntryExtension{format = Just format, span}
+  pure Entry{name = Just name, ..}
 
 {----- (3.5) Argument -----}
 
 -- | ref: (3.5)
 p_value'Entry :: Parser Entry
 p_value'Entry = label "argument" $ do
-  (value, leading) <- p_value
+  ((value, leading), span) <- withSpan p_value
   let format =
         EntryFormat
           { leading
@@ -414,7 +479,12 @@ p_value'Entry = label "argument" $ do
           , afterEq = ""
           , trailing = ""
           }
-  pure Entry{name = Nothing, value, format = Just format}
+      ext =
+        EntryExtension
+          { format = Just format
+          , span
+          }
+  pure Entry{name = Nothing, ..}
 
 {----- (3.6) Children Block -----}
 
@@ -431,6 +501,7 @@ p_node_children = label "children block" $ do
 -- value := type? node-space* (string | number | keyword)
 p_value :: Parser (Value, Text)
 p_value = label "value" $ do
+  spanStart <- startSpan
   initialAnn <- optional p_type
   postAnnWS <- withSource_ $ many p_node_space
   let (ann, leading) =
@@ -445,8 +516,14 @@ p_value = label "value" $ do
       , p_keyword
       ]
   let repr = Just repr_
+  span <- finishSpan spanStart
 
-  pure (Value{ann, data_, format = Just ValueFormat{..}}, leading)
+  let ext =
+        ValueExtension
+          { format = Just ValueFormat{..}
+          , span
+          }
+  pure (Value{..}, leading)
 
 -- | ref: (3.7)
 p_keyword :: Parser ValueData
@@ -462,21 +539,26 @@ p_keyword = label "value keyword" $ do
 -- type := '(' node-space* string node-space* ')'
 p_type :: Parser Ann
 p_type = label "type annotation" $ do
-  between (char '(') (char ')') $ do
-    beforeId <- withSource_ $ many p_node_space
-    identifier <- p_string'Identifier
-    afterId <- withSource_ $ many p_node_space
-    let format = Just AnnFormat{leading = "", trailing = "", ..}
-    pure Ann{..}
+  ((identifier, format), span) <-
+    withSpan . between (char '(') (char ')') $ do
+      beforeId <- withSource_ $ many p_node_space
+      identifier <- p_string'Identifier
+      afterId <- withSource_ $ many p_node_space
+      let format = Just AnnFormat{leading = "", trailing = "", ..}
+      pure (identifier, format)
+
+  let ext = AnnExtension{format, span}
+  pure Ann{identifier, ext}
 
 {----- (3.9) String -----}
 
 -- | ref: (3.9)
 p_string'Identifier :: Parser Identifier
 p_string'Identifier = do
-  (value, repr_) <- withSource p_string
+  ((value, repr_), span) <- withSpan . withSource $ p_string
   let repr = Just repr_
-  pure Identifier{value, format = Just IdentifierFormat{repr}}
+  let ext = IdentifierExtension{format = Just IdentifierFormat{..}, span}
+  pure Identifier{..}
 
 -- | ref: (3.9)
 -- string := identifier-string | quoted-string | raw-string ¶
@@ -501,7 +583,7 @@ p_identifier_string = label "unquoted string" $ do
     ]
 
 isValidUnquotedString :: Text -> Bool
-isValidUnquotedString = isRight . parse (p_identifier_string <* eof) ""
+isValidUnquotedString = isRight . runParser def (p_identifier_string <* eof)
 
 -- | ref: (3.10)
 -- unambiguous-ident :=
@@ -1120,6 +1202,62 @@ withSource p = do
 withSource_ :: Parser a -> Parser Text
 withSource_ = fmap snd . withSource
 
+newtype SpanStart = SpanStart (Maybe (State Text Void, SourcePos))
+
+withSpan :: Parser a -> Parser (a, Span)
+withSpan p = do
+  spanStart <- startSpan
+  a <- p
+  span <- finishSpan spanStart
+  pure (a, span)
+
+startSpan :: Parser SpanStart
+startSpan = do
+  config <- Trans.lift Reader.ask
+  if not config.includeSpans
+    then pure . SpanStart $ Nothing
+    else do
+      start <- getSourcePos
+      startState <- getParserState
+      pure . SpanStart . Just $ (startState, start)
+
+finishSpan :: SpanStart -> Parser Span
+finishSpan (SpanStart mStart) =
+  case mStart of
+    Nothing -> pure def
+    Just (startState, start) -> do
+      end <- getSourcePos
+      endState <- getParserState
+      let startLine = unPos start.sourceLine
+          startCol = unPos start.sourceColumn
+          (endLine, endCol) =
+            getEnd
+              startState
+              endState
+              startCol
+              (unPos end.sourceLine, unPos end.sourceColumn)
+      pure Span{..}
+ where
+  -- end.sourceColumn is off by 1, since the parser has already incremented
+  -- past the parsed element. So we need to simply subtract 1. However, if
+  -- end.sourceColumn == 1, it's at the start of a new line, and we need to
+  -- calculate the last column of the previous line.
+  getEnd startState endState startCol (endLine, endCol) =
+    if endCol > 1
+      then (endLine, endCol - 1)
+      else
+        let len = endState.stateOffset - startState.stateOffset
+            source = Text.take len startState.stateInput
+            endCol' = case NonEmpty.nonEmpty $ Text.lines source of
+              -- source was empty, i.e. len == 0, so endCol := startCol
+              Nothing -> startCol
+              -- there were no newlines other than the last newline, so we're
+              -- offset from startCol
+              Just (line NonEmpty.:| []) -> startCol + Text.length line - 1
+              -- source had multiple newlines, endCol is simply the length of the last line
+              Just sourceLines -> Text.length $ NonEmpty.last sourceLines
+         in (endLine - 1, endCol')
+
 repeat0 :: (Monoid a) => Parser a -> Parser a
 repeat0 = fmap mconcat . many
 
@@ -1161,16 +1299,16 @@ class HasFormat a where
   mapFormat :: (KdlFormat a -> KdlFormat a) -> a -> a
 instance HasFormat NodeList where
   type KdlFormat NodeList = NodeListFormat
-  mapFormat f NodeList{..} = NodeList{format = f <$> format, ..}
+  mapFormat f NodeList{..} = NodeList{ext = ext{NodeListExtension.format = f <$> ext.format}, ..}
 instance HasFormat Node where
   type KdlFormat Node = NodeFormat
-  mapFormat f Node{..} = Node{format = f <$> format, ..}
+  mapFormat f Node{..} = Node{ext = ext{NodeExtension.format = f <$> ext.format}, ..}
 instance HasFormat Ann where
   type KdlFormat Ann = AnnFormat
-  mapFormat f Ann{..} = Ann{format = f <$> format, ..}
+  mapFormat f Ann{..} = Ann{ext = ext{AnnExtension.format = f <$> ext.format}, ..}
 instance HasFormat Entry where
   type KdlFormat Entry = EntryFormat
-  mapFormat f Entry{..} = Entry{format = f <$> format, ..}
+  mapFormat f Entry{..} = Entry{ext = ext{EntryExtension.format = f <$> ext.format}, ..}
 
 class (HasFormat a) => HasWsFormat a where
   mapLeading :: (Text -> Text) -> a -> a
diff --git a/src/KDL/Render.hs b/src/KDL/Render.hs
index ffd0ef7..fa6048e 100644
--- a/src/KDL/Render.hs
+++ b/src/KDL/Render.hs
@@ -18,18 +18,24 @@ import Data.Text (Text)
 import Data.Text qualified as Text
 import KDL.Types (
   Ann (..),
+  AnnExtension (..),
   AnnFormat (..),
   Document,
   Entry (..),
+  EntryExtension (..),
   EntryFormat (..),
   Identifier (..),
+  IdentifierExtension (..),
   IdentifierFormat (..),
   Node (..),
+  NodeExtension (..),
   NodeFormat (..),
   NodeList (..),
+  NodeListExtension (..),
   NodeListFormat (..),
   Value (..),
   ValueData (..),
+  ValueExtension (..),
   ValueFormat (..),
  )
 
@@ -41,31 +47,31 @@ type IndentLevel = Int
 renderNodeList :: IndentLevel -> NodeList -> Text
 renderNodeList lvl NodeList{..} =
   Text.concat
-    [ maybe (if lvl > 0 then "\n" else "") (.leading) format
+    [ maybe (if lvl > 0 then "\n" else "") (.leading) ext.format
     , foldMap (renderNode lvl) nodes
-    , maybe (indent (lvl - 1)) (.trailing) format
+    , maybe (indent (lvl - 1)) (.trailing) ext.format
     ]
 
 renderNode :: IndentLevel -> Node -> Text
 renderNode lvl Node{..} =
   Text.concat
-    [ maybe (indent lvl) (.leading) format
+    [ maybe (indent lvl) (.leading) ext.format
     , maybe "" renderAnn ann
     , renderIdentifier name
     , foldMap renderEntry entries
     , let def_ = if children == Nothing then "" else " "
-       in maybe def_ (.beforeChildren) format
+       in maybe def_ (.beforeChildren) ext.format
     , case children of
         Nothing -> ""
         Just nodes -> renderChildren lvl nodes
-    , maybe "" (.beforeTerminator) format
-    , maybe "\n" (.terminator) format
-    , maybe "" (.trailing) format
+    , maybe "" (.beforeTerminator) ext.format
+    , maybe "\n" (.terminator) ext.format
+    , maybe "" (.trailing) ext.format
     ]
 
 renderChildren :: IndentLevel -> NodeList -> Text
 renderChildren lvl nodeList =
-  case nodeList.format of
+  case nodeList.ext.format of
     -- Special case empty node list to render as "{}"
     Nothing | null nodeList.nodes -> "{}"
     _ -> "{" <> renderNodeList (lvl + 1) nodeList <> "}"
@@ -76,37 +82,37 @@ indent lvl = Text.replicate lvl "  "
 renderEntry :: Entry -> Text
 renderEntry Entry{..} =
   Text.concat
-    [ maybe " " (.leading) format
+    [ maybe " " (.leading) ext.format
     , case name of
         Nothing -> renderValue value
         Just nameId ->
           Text.concat
             [ renderIdentifier nameId
-            , maybe "" (.afterKey) format
+            , maybe "" (.afterKey) ext.format
             , "="
-            , maybe "" (.afterEq) format
+            , maybe "" (.afterEq) ext.format
             , renderValue value
             ]
-    , maybe "" (.trailing) format
+    , maybe "" (.trailing) ext.format
     ]
 
 renderAnn :: Ann -> Text
 renderAnn Ann{..} =
   Text.concat
-    [ maybe "" (.leading) format
+    [ maybe "" (.leading) ext.format
     , "("
-    , maybe "" (.beforeId) format
+    , maybe "" (.beforeId) ext.format
     , renderIdentifier identifier
-    , maybe "" (.afterId) format
+    , maybe "" (.afterId) ext.format
     , ")"
-    , maybe "" (.trailing) format
+    , maybe "" (.trailing) ext.format
     ]
 
 renderValue :: Value -> Text
 renderValue Value{..} =
   Text.concat
     [ maybe "" renderAnn ann
-    , fromMaybe (renderValueData data_) (format >>= (.repr))
+    , fromMaybe (renderValueData data_) (ext.format >>= (.repr))
     ]
 
 renderValueData :: ValueData -> Text
@@ -191,4 +197,4 @@ renderValueData = \case
     c -> Text.singleton c
 
 renderIdentifier :: Identifier -> Text
-renderIdentifier ident = fromMaybe ident.value (ident.format >>= (.repr))
+renderIdentifier ident = fromMaybe ident.value (ident.ext.format >>= (.repr))
diff --git a/src/KDL/Types.hs b/src/KDL/Types.hs
index 992e0dc..6e7d1af 100644
--- a/src/KDL/Types.hs
+++ b/src/KDL/Types.hs
@@ -19,6 +19,7 @@ module KDL.Types (
 
   -- * NodeList
   NodeList (..),
+  NodeListExtension (..),
   NodeListFormat (..),
   fromNodeList,
   nodeListFormat,
@@ -33,6 +34,7 @@ module KDL.Types (
 
   -- * Node
   Node (..),
+  NodeExtension (..),
   NodeFormat (..),
   nodeAnn,
   nodeName,
@@ -48,6 +50,7 @@ module KDL.Types (
 
   -- * Entry
   Entry (..),
+  EntryExtension (..),
   EntryFormat (..),
   entryName,
   entryValue,
@@ -55,6 +58,7 @@ module KDL.Types (
 
   -- * Value
   Value (..),
+  ValueExtension (..),
   ValueFormat (..),
   valueAnn,
   valueData,
@@ -63,17 +67,22 @@ module KDL.Types (
 
   -- * Ann
   Ann (..),
+  AnnExtension (..),
   AnnFormat (..),
   annIdentifier,
   annFormat,
 
   -- * Identifier
   Identifier (..),
+  IdentifierExtension (..),
   IdentifierFormat (..),
   fromIdentifier,
   identifierFormat,
   toIdentifier,
 
+  -- * Span
+  Span (..),
+
   -- * Re-exports
   def,
 ) where
@@ -97,7 +106,13 @@ docNodes = fromNodeList
 
 data NodeList = NodeList
   { nodes :: [Node]
-  , format :: Maybe NodeListFormat
+  , ext :: NodeListExtension
+  }
+  deriving (Show, Eq)
+
+data NodeListExtension = NodeListExtension
+  { format :: Maybe NodeListFormat
+  , span :: Span
   }
   deriving (Show, Eq)
 
@@ -109,6 +124,12 @@ data NodeListFormat = NodeListFormat
   }
   deriving (Show, Eq)
 
+instance Default NodeListExtension where
+  def =
+    NodeListExtension
+      { format = def
+      , span = def
+      }
 instance Default NodeListFormat where
   def =
     NodeListFormat
@@ -120,7 +141,7 @@ fromNodeList :: NodeList -> [Node]
 fromNodeList = (.nodes)
 
 nodeListFormat :: NodeList -> Maybe NodeListFormat
-nodeListFormat = (.format)
+nodeListFormat = (.ext.format)
 
 -- | A helper to get all nodes with the given name
 filterNodes :: Text -> NodeList -> [Node]
@@ -208,7 +229,13 @@ getDashNodesAt name = maybe [] (filterNodes "-") . (nodeChildren <=< lookupNode
 
 data Ann = Ann
   { identifier :: Identifier
-  , format :: Maybe AnnFormat
+  , ext :: AnnExtension
+  }
+  deriving (Show, Eq)
+
+data AnnExtension = AnnExtension
+  { format :: Maybe AnnFormat
+  , span :: Span
   }
   deriving (Show, Eq)
 
@@ -224,6 +251,12 @@ data AnnFormat = AnnFormat
   }
   deriving (Show, Eq)
 
+instance Default AnnExtension where
+  def =
+    AnnExtension
+      { format = def
+      , span = def
+      }
 instance Default AnnFormat where
   def =
     AnnFormat
@@ -237,7 +270,7 @@ annIdentifier :: Ann -> Identifier
 annIdentifier = (.identifier)
 
 annFormat :: Ann -> Maybe AnnFormat
-annFormat = (.format)
+annFormat = (.ext.format)
 
 {----- Node -----}
 
@@ -246,7 +279,13 @@ data Node = Node
   , name :: Identifier
   , entries :: [Entry]
   , children :: Maybe NodeList
-  , format :: Maybe NodeFormat
+  , ext :: NodeExtension
+  }
+  deriving (Show, Eq)
+
+data NodeExtension = NodeExtension
+  { format :: Maybe NodeFormat
+  , span :: Span
   }
   deriving (Show, Eq)
 
@@ -264,6 +303,12 @@ data NodeFormat = NodeFormat
   }
   deriving (Show, Eq)
 
+instance Default NodeExtension where
+  def =
+    NodeExtension
+      { format = def
+      , span = def
+      }
 instance Default NodeFormat where
   def =
     NodeFormat
@@ -287,7 +332,7 @@ nodeChildren :: Node -> Maybe NodeList
 nodeChildren = (.children)
 
 nodeFormat :: Node -> Maybe NodeFormat
-nodeFormat = (.format)
+nodeFormat = (.ext.format)
 
 -- | Get all the positional arguments of the node.
 getArgs :: Node -> [Value]
@@ -318,7 +363,13 @@ data Entry = Entry
   { name :: Maybe Identifier
   -- ^ The name of the entry, if it's a property, Nothing if it's a positional arg
   , value :: Value
-  , format :: Maybe EntryFormat
+  , ext :: EntryExtension
+  }
+  deriving (Show, Eq)
+
+data EntryExtension = EntryExtension
+  { format :: Maybe EntryFormat
+  , span :: Span
   }
   deriving (Show, Eq)
 
@@ -334,6 +385,12 @@ data EntryFormat = EntryFormat
   }
   deriving (Show, Eq)
 
+instance Default EntryExtension where
+  def =
+    EntryExtension
+      { format = def
+      , span = def
+      }
 instance Default EntryFormat where
   def =
     EntryFormat
@@ -350,14 +407,20 @@ entryValue :: Entry -> Value
 entryValue = (.value)
 
 entryFormat :: Entry -> Maybe EntryFormat
-entryFormat = (.format)
+entryFormat = (.ext.format)
 
 {----- Value -----}
 
 data Value = Value
   { ann :: Maybe Ann
   , data_ :: ValueData
-  , format :: Maybe ValueFormat
+  , ext :: ValueExtension
+  }
+  deriving (Show, Eq)
+
+data ValueExtension = ValueExtension
+  { format :: Maybe ValueFormat
+  , span :: Span
   }
   deriving (Show, Eq)
 
@@ -367,6 +430,12 @@ data ValueFormat = ValueFormat
   }
   deriving (Show, Eq)
 
+instance Default ValueExtension where
+  def =
+    ValueExtension
+      { format = def
+      , span = def
+      }
 instance Default ValueFormat where
   def =
     ValueFormat
@@ -380,7 +449,7 @@ valueData :: Value -> ValueData
 valueData = (.data_)
 
 valueFormat :: Value -> Maybe ValueFormat
-valueFormat = (.format)
+valueFormat = (.ext.format)
 
 data ValueData
   = String Text
@@ -396,7 +465,13 @@ data ValueData
 
 data Identifier = Identifier
   { value :: Text
-  , format :: Maybe IdentifierFormat
+  , ext :: IdentifierExtension
+  }
+  deriving (Show, Eq, Ord)
+
+data IdentifierExtension = IdentifierExtension
+  { format :: Maybe IdentifierFormat
+  , span :: Span
   }
   deriving (Show, Eq, Ord)
 
@@ -405,6 +480,12 @@ data IdentifierFormat = IdentifierFormat
   }
   deriving (Show, Eq, Ord)
 
+instance Default IdentifierExtension where
+  def =
+    IdentifierExtension
+      { format = def
+      , span = def
+      }
 instance Default IdentifierFormat where
   def =
     IdentifierFormat
@@ -415,7 +496,28 @@ fromIdentifier :: Identifier -> Text
 fromIdentifier = (.value)
 
 identifierFormat :: Identifier -> Maybe IdentifierFormat
-identifierFormat = (.format)
+identifierFormat = (.ext.format)
 
 toIdentifier :: Text -> Identifier
-toIdentifier value = Identifier{value = value, format = Nothing}
+toIdentifier value = Identifier{value = value, ext = def}
+
+{----- Span -----}
+
+-- | The span of a KDL element, if parsed with 'includeSpans'. If 'includeSpans'
+-- was not enabled, all fields are set to 0.
+data Span = Span
+  { startLine :: Int
+  , startCol :: Int
+  , endLine :: Int
+  , endCol :: Int
+  }
+  deriving (Show, Eq, Ord)
+
+instance Default Span where
+  def =
+    Span
+      { startLine = 0
+      , startCol = 0
+      , endLine = 0
+      , endCol = 0
+      }
diff --git a/test/KDL/Decoder/ArrowSpec.hs b/test/KDL/Decoder/ArrowSpec.hs
index 1022753..99d2756 100644
--- a/test/KDL/Decoder/ArrowSpec.hs
+++ b/test/KDL/Decoder/ArrowSpec.hs
@@ -43,16 +43,16 @@ apiSpec = do
             expected =
               Node
                 { ann = Nothing
-                , name = Identifier{value = "foo", format = Nothing}
+                , name = Identifier{value = "foo", ext = KDL.def}
                 , entries =
                     [ Entry
                         { name = Nothing
-                        , value = Value{ann = Nothing, data_ = Number 1.0, format = Nothing}
-                        , format = Nothing
+                        , value = Value{ann = Nothing, data_ = Number 1.0, ext = KDL.def}
+                        , ext = KDL.def
                         }
                     ]
                 , children = Nothing
-                , format = Nothing
+                , ext = KDL.def
                 }
         KDL.decodeWith decoder config `shouldBe` Right expected
 
@@ -64,10 +64,10 @@ apiSpec = do
             fooNode =
               Node
                 { ann = Nothing
-                , name = Identifier{value = "foo", format = Nothing}
+                , name = Identifier{value = "foo", ext = KDL.def}
                 , entries = []
                 , children = Nothing
-                , format = Nothing
+                , ext = KDL.def
                 }
         KDL.decodeWith decoder config `shouldBe` Right expected
 
@@ -81,10 +81,10 @@ apiSpec = do
             node name =
               Node
                 { ann = Nothing
-                , name = Identifier{value = name, format = Nothing}
+                , name = Identifier{value = name, ext = KDL.def}
                 , entries = []
                 , children = Nothing
-                , format = Nothing
+                , ext = KDL.def
                 }
         KDL.decodeWith decoder config `shouldBe` Right expected
 
@@ -174,24 +174,24 @@ apiSpec = do
             fooNode2 =
               Node
                 { ann = Nothing
-                , name = Identifier{value = "foo", format = Nothing}
+                , name = Identifier{value = "foo", ext = KDL.def}
                 , entries =
                     [ Entry
                         { name = Nothing
-                        , value = Value{ann = Nothing, data_ = Number 2.0, format = Nothing}
-                        , format = Nothing
+                        , value = Value{ann = Nothing, data_ = Number 2.0, ext = KDL.def}
+                        , ext = KDL.def
                         }
                     ]
                 , children = Nothing
-                , format = Nothing
+                , ext = KDL.def
                 }
             barNode =
               Node
                 { ann = Nothing
-                , name = Identifier{value = "bar", format = Nothing}
+                , name = Identifier{value = "bar", ext = KDL.def}
                 , entries = []
                 , children = Nothing
-                , format = Nothing
+                , ext = KDL.def
                 }
         KDL.decodeWith decoder config `shouldBe` Right expected
 
@@ -519,13 +519,13 @@ apiSpec = do
             node name children =
               Node
                 { ann = Nothing
-                , name = Identifier{value = name, format = Nothing}
+                , name = Identifier{value = name, ext = KDL.def}
                 , entries = []
                 , children =
                     if null children
                       then Nothing
-                      else Just NodeList{nodes = children, format = Nothing}
-                , format = Nothing
+                      else Just NodeList{nodes = children, ext = KDL.def}
+                , ext = KDL.def
                 }
         KDL.decodeWith decoder config `shouldBe` Right expected
 
@@ -850,16 +850,16 @@ apiSpec = do
             expected =
               Node
                 { ann = Nothing
-                , name = Identifier{value = "bar", format = Nothing}
+                , name = Identifier{value = "bar", ext = KDL.def}
                 , entries =
                     [ Entry
                         { name = Nothing
-                        , value = Value{ann = Nothing, data_ = String "test", format = Nothing}
-                        , format = Nothing
+                        , value = Value{ann = Nothing, data_ = String "test", ext = KDL.def}
+                        , ext = KDL.def
                         }
                     ]
                 , children = Nothing
-                , format = Nothing
+                , ext = KDL.def
                 }
         decodeNode "foo" decoder config `shouldBe` Right expected
 
@@ -891,7 +891,7 @@ apiSpec = do
               Value
                 { ann = Nothing
                 , data_ = data_
-                , format = Nothing
+                , ext = KDL.def
                 }
         KDL.decodeWith decoder config
           `shouldBe` Right [val $ Number 1, val $ String "asdf", val $ Bool True]
diff --git a/test/KDL/Decoder/MonadSpec.hs b/test/KDL/Decoder/MonadSpec.hs
index ff9401f..0780d36 100644
--- a/test/KDL/Decoder/MonadSpec.hs
+++ b/test/KDL/Decoder/MonadSpec.hs
@@ -37,16 +37,16 @@ apiSpec = do
             expected =
               Node
                 { ann = Nothing
-                , name = Identifier{value = "foo", format = Nothing}
+                , name = Identifier{value = "foo", ext = KDL.def}
                 , entries =
                     [ Entry
                         { name = Nothing
-                        , value = Value{ann = Nothing, data_ = Number 1.0, format = Nothing}
-                        , format = Nothing
+                        , value = Value{ann = Nothing, data_ = Number 1.0, ext = KDL.def}
+                        , ext = KDL.def
                         }
                     ]
                 , children = Nothing
-                , format = Nothing
+                , ext = KDL.def
                 }
         KDL.decodeWith decoder config `shouldBe` Right expected
 
@@ -58,10 +58,10 @@ apiSpec = do
             fooNode =
               Node
                 { ann = Nothing
-                , name = Identifier{value = "foo", format = Nothing}
+                , name = Identifier{value = "foo", ext = KDL.def}
                 , entries = []
                 , children = Nothing
-                , format = Nothing
+                , ext = KDL.def
                 }
         KDL.decodeWith decoder config `shouldBe` Right expected
 
@@ -75,10 +75,10 @@ apiSpec = do
             node name =
               Node
                 { ann = Nothing
-                , name = Identifier{value = name, format = Nothing}
+                , name = Identifier{value = name, ext = KDL.def}
                 , entries = []
                 , children = Nothing
-                , format = Nothing
+                , ext = KDL.def
                 }
         KDL.decodeWith decoder config `shouldBe` Right expected
 
@@ -168,24 +168,24 @@ apiSpec = do
             fooNode2 =
               Node
                 { ann = Nothing
-                , name = Identifier{value = "foo", format = Nothing}
+                , name = Identifier{value = "foo", ext = KDL.def}
                 , entries =
                     [ Entry
                         { name = Nothing
-                        , value = Value{ann = Nothing, data_ = Number 2.0, format = Nothing}
-                        , format = Nothing
+                        , value = Value{ann = Nothing, data_ = Number 2.0, ext = KDL.def}
+                        , ext = KDL.def
                         }
                     ]
                 , children = Nothing
-                , format = Nothing
+                , ext = KDL.def
                 }
             barNode =
               Node
                 { ann = Nothing
-                , name = Identifier{value = "bar", format = Nothing}
+                , name = Identifier{value = "bar", ext = KDL.def}
                 , entries = []
                 , children = Nothing
-                , format = Nothing
+                , ext = KDL.def
                 }
         KDL.decodeWith decoder config `shouldBe` Right expected
 
@@ -513,13 +513,13 @@ apiSpec = do
             node name children =
               Node
                 { ann = Nothing
-                , name = Identifier{value = name, format = Nothing}
+                , name = Identifier{value = name, ext = KDL.def}
                 , entries = []
                 , children =
                     if null children
                       then Nothing
-                      else Just NodeList{nodes = children, format = Nothing}
-                , format = Nothing
+                      else Just NodeList{nodes = children, ext = KDL.def}
+                , ext = KDL.def
                 }
         KDL.decodeWith decoder config `shouldBe` Right expected
 
@@ -844,16 +844,16 @@ apiSpec = do
             expected =
               Node
                 { ann = Nothing
-                , name = Identifier{value = "bar", format = Nothing}
+                , name = Identifier{value = "bar", ext = KDL.def}
                 , entries =
                     [ Entry
                         { name = Nothing
-                        , value = Value{ann = Nothing, data_ = String "test", format = Nothing}
-                        , format = Nothing
+                        , value = Value{ann = Nothing, data_ = String "test", ext = KDL.def}
+                        , ext = KDL.def
                         }
                     ]
                 , children = Nothing
-                , format = Nothing
+                , ext = KDL.def
                 }
         decodeNode "foo" decoder config `shouldBe` Right expected
 
@@ -885,7 +885,7 @@ apiSpec = do
               Value
                 { ann = Nothing
                 , data_ = data_
-                , format = Nothing
+                , ext = KDL.def
                 }
         KDL.decodeWith decoder config
           `shouldBe` Right [val $ Number 1, val $ String "asdf", val $ Bool True]
diff --git a/test/KDL/ParserSpec.hs b/test/KDL/ParserSpec.hs
index 5f9031c..613fbec 100644
--- a/test/KDL/ParserSpec.hs
+++ b/test/KDL/ParserSpec.hs
@@ -28,6 +28,11 @@ spec = do
       -- TODO: add more
       test "Unquoted numeric prop name" "foo 123=123"
 
+  describe "parseWith" $ do
+    it "parses a KDL document with spans" $ do
+      KDL.parseWith KDL.def{KDL.includeSpans = True} "foo 1 2 {\n  bar 3\n}"
+        `shouldSatisfy` P.right P.matchesSnapshot
+
   -- Most behavior tested in `parse` tests
   describe "parseFile" $ do
     it "parses a KDL document from a filepath" $ do
diff --git a/test/KDL/RenderSpec.hs b/test/KDL/RenderSpec.hs
index b8ca0a7..3aa2ca2 100644
--- a/test/KDL/RenderSpec.hs
+++ b/test/KDL/RenderSpec.hs
@@ -11,11 +11,11 @@ spec :: Spec
 spec = do
   describe "render" $ do
     describe "default formatting" $ do
-      let ident s = KDL.Identifier{value = s, format = KDL.def}
+      let ident s = KDL.Identifier{value = s, ext = KDL.def}
           fooAnn =
             KDL.Ann
               { identifier = ident "Foo"
-              , format = KDL.def
+              , ext = KDL.def
               }
           doc =
             KDL.NodeList
@@ -30,9 +30,9 @@ spec = do
                                   KDL.Value
                                     { ann = Just fooAnn
                                     , data_ = KDL.Number 123
-                                    , format = KDL.def
+                                    , ext = KDL.def
                                     }
-                              , format = KDL.def
+                              , ext = KDL.def
                               }
                           , KDL.Entry
                               { name = Just $ ident "a"
@@ -40,9 +40,9 @@ spec = do
                                   KDL.Value
                                     { ann = Just fooAnn
                                     , data_ = KDL.Number 123
-                                    , format = KDL.def
+                                    , ext = KDL.def
                                     }
-                              , format = KDL.def
+                              , ext = KDL.def
                               }
                           , KDL.Entry
                               { name = Nothing
@@ -50,9 +50,9 @@ spec = do
                                   KDL.Value
                                     { ann = Nothing
                                     , data_ = KDL.String "test"
-                                    , format = KDL.def
+                                    , ext = KDL.def
                                     }
-                              , format = KDL.def
+                              , ext = KDL.def
                               }
                           , KDL.Entry
                               { name = Just $ ident "b"
@@ -60,9 +60,9 @@ spec = do
                                   KDL.Value
                                     { ann = Nothing
                                     , data_ = KDL.String "test"
-                                    , format = KDL.def
+                                    , ext = KDL.def
                                     }
-                              , format = KDL.def
+                              , ext = KDL.def
                               }
                           ]
                       , children =
@@ -82,17 +82,17 @@ spec = do
                                                       , name = ident "baz"
                                                       , entries = []
                                                       , children = Nothing
-                                                      , format = KDL.def
+                                                      , ext = KDL.def
                                                       }
                                                   ]
-                                              , format = KDL.def
+                                              , ext = KDL.def
                                               }
-                                      , format = KDL.def
+                                      , ext = KDL.def
                                       }
                                   ]
-                              , format = KDL.def
+                              , ext = KDL.def
                               }
-                      , format = KDL.def
+                      , ext = KDL.def
                       }
                   , KDL.Node
                       { ann = Just fooAnn
@@ -102,12 +102,12 @@ spec = do
                           Just
                             KDL.NodeList
                               { nodes = []
-                              , format = KDL.def
+                              , ext = KDL.def
                               }
-                      , format = KDL.def
+                      , ext = KDL.def
                       }
                   ]
-              , format = KDL.def
+              , ext = KDL.def
               }
 
       it "renders correctly" $ do
diff --git a/test/KDL/TestUtils/AST.hs b/test/KDL/TestUtils/AST.hs
index c785ff2..53a9d7a 100644
--- a/test/KDL/TestUtils/AST.hs
+++ b/test/KDL/TestUtils/AST.hs
@@ -12,7 +12,7 @@ instance ScrubFormat NodeList where
   scrubFormat NodeList{..} =
     NodeList
       { nodes = map scrubFormat nodes
-      , format = Nothing
+      , ext = def
       }
 instance ScrubFormat Node where
   scrubFormat Node{..} =
@@ -21,31 +21,31 @@ instance ScrubFormat Node where
       , name = scrubFormat name
       , entries = map scrubFormat entries
       , children = scrubFormat <$> children
-      , format = Nothing
+      , ext = def
       }
 instance ScrubFormat Entry where
   scrubFormat Entry{..} =
     Entry
       { name = scrubFormat <$> name
       , value = scrubFormat value
-      , format = Nothing
+      , ext = def
       }
 instance ScrubFormat Value where
   scrubFormat Value{..} =
     Value
       { ann = scrubFormat <$> ann
       , data_ = data_
-      , format = Nothing
+      , ext = def
       }
 instance ScrubFormat Ann where
   scrubFormat Ann{..} =
     Ann
       { identifier = scrubFormat identifier
-      , format = Nothing
+      , ext = def
       }
 instance ScrubFormat Identifier where
   scrubFormat Identifier{..} =
     Identifier
       { value = value
-      , format = Nothing
+      , ext = def
       }
diff --git a/test/KDL/__snapshots__/ParserSpec.snap.md b/test/KDL/__snapshots__/ParserSpec.snap.md
index b1f9737..eae5d14 100644
--- a/test/KDL/__snapshots__/ParserSpec.snap.md
+++ b/test/KDL/__snapshots__/ParserSpec.snap.md
@@ -21,7 +21,12 @@ NodeList
           , name =
               Identifier
                 { value = "foo"
-                , format = Just IdentifierFormat { repr = Just "foo" }
+                , ext =
+                    IdentifierExtension
+                      { format = Just IdentifierFormat { repr = Just "foo" }
+                      , span =
+                          Span { startLine = 0 , startCol = 0 , endLine = 0 , endCol = 0 }
+                      }
                 }
           , entries =
               [ Entry
@@ -29,18 +34,33 @@ NodeList
                       Just
                         Identifier
                           { value = "hello"
-                          , format = Just IdentifierFormat { repr = Just "hello" }
+                          , ext =
+                              IdentifierExtension
+                                { format = Just IdentifierFormat { repr = Just "hello" }
+                                , span =
+                                    Span { startLine = 0 , startCol = 0 , endLine = 0 , endCol = 0 }
+                                }
                           }
                   , value =
                       Value
                         { ann = Nothing
                         , data_ = String "world"
-                        , format = Just ValueFormat { repr = Just "world" }
+                        , ext =
+                            ValueExtension
+                              { format = Just ValueFormat { repr = Just "world" }
+                              , span =
+                                  Span { startLine = 0 , startCol = 0 , endLine = 0 , endCol = 0 }
+                              }
+                        }
+                  , ext =
+                      EntryExtension
+                        { format =
+                            Just
+                              EntryFormat
+                                { leading = " " , afterKey = "" , afterEq = "" , trailing = "" }
+                        , span =
+                            Span { startLine = 0 , startCol = 0 , endLine = 0 , endCol = 0 }
                         }
-                  , format =
-                      Just
-                        EntryFormat
-                          { leading = " " , afterKey = "" , afterEq = "" , trailing = "" }
                   }
               , Entry
                   { name = Nothing
@@ -48,12 +68,22 @@ NodeList
                       Value
                         { ann = Nothing
                         , data_ = Number 1.0
-                        , format = Just ValueFormat { repr = Just "1.0" }
+                        , ext =
+                            ValueExtension
+                              { format = Just ValueFormat { repr = Just "1.0" }
+                              , span =
+                                  Span { startLine = 0 , startCol = 0 , endLine = 0 , endCol = 0 }
+                              }
+                        }
+                  , ext =
+                      EntryExtension
+                        { format =
+                            Just
+                              EntryFormat
+                                { leading = " " , afterKey = "" , afterEq = "" , trailing = "" }
+                        , span =
+                            Span { startLine = 0 , startCol = 0 , endLine = 0 , endCol = 0 }
                         }
-                  , format =
-                      Just
-                        EntryFormat
-                          { leading = " " , afterKey = "" , afterEq = "" , trailing = "" }
                   }
               ]
           , children =
@@ -65,34 +95,238 @@ NodeList
                           , name =
                               Identifier
                                 { value = "bar"
-                                , format = Just IdentifierFormat { repr = Just "bar" }
+                                , ext =
+                                    IdentifierExtension
+                                      { format = Just IdentifierFormat { repr = Just "bar" }
+                                      , span =
+                                          Span
+                                            { startLine = 0
+                                            , startCol = 0
+                                            , endLine = 0
+                                            , endCol = 0
+                                            }
+                                      }
                                 }
                           , entries = []
                           , children = Nothing
-                          , format =
-                              Just
-                                NodeFormat
-                                  { leading = " "
-                                  , beforeChildren = ""
-                                  , beforeTerminator = ""
-                                  , terminator = ";"
-                                  , trailing = ""
-                                  }
+                          , ext =
+                              NodeExtension
+                                { format =
+                                    Just
+                                      NodeFormat
+                                        { leading = " "
+                                        , beforeChildren = ""
+                                        , beforeTerminator = ""
+                                        , terminator = ";"
+                                        , trailing = ""
+                                        }
+                                , span =
+                                    Span { startLine = 0 , startCol = 0 , endLine = 0 , endCol = 0 }
+                                }
                           }
                       ]
-                  , format = Just NodeListFormat { leading = "" , trailing = " " }
+                  , ext =
+                      NodeListExtension
+                        { format = Just NodeListFormat { leading = "" , trailing = " " }
+                        , span =
+                            Span { startLine = 0 , startCol = 0 , endLine = 0 , endCol = 0 }
+                        }
                   }
-          , format =
+          , ext =
+              NodeExtension
+                { format =
+                    Just
+                      NodeFormat
+                        { leading = ""
+                        , beforeChildren = " "
+                        , beforeTerminator = ""
+                        , terminator = ""
+                        , trailing = ""
+                        }
+                , span =
+                    Span { startLine = 0 , startCol = 0 , endLine = 0 , endCol = 0 }
+                }
+          }
+      ]
+  , ext =
+      NodeListExtension
+        { format = Just NodeListFormat { leading = "" , trailing = "" }
+        , span =
+            Span { startLine = 0 , startCol = 0 , endLine = 0 , endCol = 0 }
+        }
+  }
+```
+
+## parseWith / parses a KDL document with spans
+
+```haskell
+NodeList
+  { nodes =
+      [ Node
+          { ann = Nothing
+          , name =
+              Identifier
+                { value = "foo"
+                , ext =
+                    IdentifierExtension
+                      { format = Just IdentifierFormat { repr = Just "foo" }
+                      , span =
+                          Span { startLine = 1 , startCol = 1 , endLine = 1 , endCol = 3 }
+                      }
+                }
+          , entries =
+              [ Entry
+                  { name = Nothing
+                  , value =
+                      Value
+                        { ann = Nothing
+                        , data_ = Number 1.0
+                        , ext =
+                            ValueExtension
+                              { format = Just ValueFormat { repr = Just "1" }
+                              , span =
+                                  Span { startLine = 1 , startCol = 5 , endLine = 1 , endCol = 5 }
+                              }
+                        }
+                  , ext =
+                      EntryExtension
+                        { format =
+                            Just
+                              EntryFormat
+                                { leading = " " , afterKey = "" , afterEq = "" , trailing = "" }
+                        , span =
+                            Span { startLine = 1 , startCol = 5 , endLine = 1 , endCol = 5 }
+                        }
+                  }
+              , Entry
+                  { name = Nothing
+                  , value =
+                      Value
+                        { ann = Nothing
+                        , data_ = Number 2.0
+                        , ext =
+                            ValueExtension
+                              { format = Just ValueFormat { repr = Just "2" }
+                              , span =
+                                  Span { startLine = 1 , startCol = 7 , endLine = 1 , endCol = 7 }
+                              }
+                        }
+                  , ext =
+                      EntryExtension
+                        { format =
+                            Just
+                              EntryFormat
+                                { leading = " " , afterKey = "" , afterEq = "" , trailing = "" }
+                        , span =
+                            Span { startLine = 1 , startCol = 7 , endLine = 1 , endCol = 7 }
+                        }
+                  }
+              ]
+          , children =
               Just
-                NodeFormat
-                  { leading = ""
-                  , beforeChildren = " "
-                  , beforeTerminator = ""
-                  , terminator = ""
-                  , trailing = ""
+                NodeList
+                  { nodes =
+                      [ Node
+                          { ann = Nothing
+                          , name =
+                              Identifier
+                                { value = "bar"
+                                , ext =
+                                    IdentifierExtension
+                                      { format = Just IdentifierFormat { repr = Just "bar" }
+                                      , span =
+                                          Span
+                                            { startLine = 2
+                                            , startCol = 3
+                                            , endLine = 2
+                                            , endCol = 5
+                                            }
+                                      }
+                                }
+                          , entries =
+                              [ Entry
+                                  { name = Nothing
+                                  , value =
+                                      Value
+                                        { ann = Nothing
+                                        , data_ = Number 3.0
+                                        , ext =
+                                            ValueExtension
+                                              { format = Just ValueFormat { repr = Just "3" }
+                                              , span =
+                                                  Span
+                                                    { startLine = 2
+                                                    , startCol = 7
+                                                    , endLine = 2
+                                                    , endCol = 7
+                                                    }
+                                              }
+                                        }
+                                  , ext =
+                                      EntryExtension
+                                        { format =
+                                            Just
+                                              EntryFormat
+                                                { leading = " "
+                                                , afterKey = ""
+                                                , afterEq = ""
+                                                , trailing = ""
+                                                }
+                                        , span =
+                                            Span
+                                              { startLine = 2
+                                              , startCol = 7
+                                              , endLine = 2
+                                              , endCol = 7
+                                              }
+                                        }
+                                  }
+                              ]
+                          , children = Nothing
+                          , ext =
+                              NodeExtension
+                                { format =
+                                    Just
+                                      NodeFormat
+                                        { leading = "\n  "
+                                        , beforeChildren = ""
+                                        , beforeTerminator = ""
+                                        , terminator = "\n"
+                                        , trailing = ""
+                                        }
+                                , span =
+                                    Span { startLine = 2 , startCol = 3 , endLine = 2 , endCol = 7 }
+                                }
+                          }
+                      ]
+                  , ext =
+                      NodeListExtension
+                        { format = Just NodeListFormat { leading = "" , trailing = "" }
+                        , span =
+                            Span { startLine = 2 , startCol = 3 , endLine = 2 , endCol = 7 }
+                        }
                   }
+          , ext =
+              NodeExtension
+                { format =
+                    Just
+                      NodeFormat
+                        { leading = ""
+                        , beforeChildren = " "
+                        , beforeTerminator = ""
+                        , terminator = ""
+                        , trailing = ""
+                        }
+                , span =
+                    Span { startLine = 1 , startCol = 1 , endLine = 3 , endCol = 1 }
+                }
           }
       ]
-  , format = Just NodeListFormat { leading = "" , trailing = "" }
+  , ext =
+      NodeListExtension
+        { format = Just NodeListFormat { leading = "" , trailing = "" }
+        , span =
+            Span { startLine = 1 , startCol = 1 , endLine = 3 , endCol = 1 }
+        }
   }
 ```