Add behavioral tests for examples from the YAML spec (#1835)

## Changes

I took the examples from https://yaml.org/spec/1.2.2.

The required modifications to the loader are:
* Correctly parse floating point infinities and NaN
* Correctly parse octal numbers per the YAML 1.2 spec
* Treat "null" keys in a map as valid

## Tests

Existing and new unit tests pass.

libs/dyn/dynassert/dump.go

@@ -0,0 +1,60 @@
+package dynassert
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/databricks/cli/libs/dyn"
+)
+
+// Dump returns the Go code to recreate the given value.
+func Dump(v dyn.Value) string {
+	var sb strings.Builder
+	dump(v, &sb)
+	return sb.String()
+}
+
+func dump(v dyn.Value, sb *strings.Builder) {
+	sb.WriteString("dyn.NewValue(\n")
+
+	switch v.Kind() {
+	case dyn.KindMap:
+		sb.WriteString("map[string]dyn.Value{")
+		m := v.MustMap()
+		for _, p := range m.Pairs() {
+			sb.WriteString(fmt.Sprintf("\n%q: ", p.Key.MustString()))
+			dump(p.Value, sb)
+			sb.WriteByte(',')
+		}
+		sb.WriteString("\n},\n")
+	case dyn.KindSequence:
+		sb.WriteString("[]dyn.Value{\n")
+		for _, e := range v.MustSequence() {
+			dump(e, sb)
+			sb.WriteByte(',')
+		}
+		sb.WriteString("},\n")
+	case dyn.KindString:
+		sb.WriteString(fmt.Sprintf("%q,\n", v.MustString()))
+	case dyn.KindBool:
+		sb.WriteString(fmt.Sprintf("%t,\n", v.MustBool()))
+	case dyn.KindInt:
+		sb.WriteString(fmt.Sprintf("%d,\n", v.MustInt()))
+	case dyn.KindFloat:
+		sb.WriteString(fmt.Sprintf("%f,\n", v.MustFloat()))
+	case dyn.KindTime:
+		sb.WriteString(fmt.Sprintf("dyn.NewTime(%q),\n", v.MustTime().String()))
+	case dyn.KindNil:
+		sb.WriteString("nil,\n")
+	default:
+		panic(fmt.Sprintf("unhandled kind: %v", v.Kind()))
+	}
+
+	// Add location
+	sb.WriteString("[]dyn.Location{")
+	for _, l := range v.Locations() {
+		sb.WriteString(fmt.Sprintf("{File: %q, Line: %d, Column: %d},", l.File, l.Line, l.Column))
+	}
+	sb.WriteString("},\n")
+	sb.WriteString(")")
+}

libs/dyn/yamlloader/loader.go

@@ -105,6 +105,9 @@ func (d *loader) loadMapping(node *yaml.Node, loc dyn.Location) (dyn.Value, erro
 		switch st {
 		case "!!str":
 			// OK
+		case "!!null":
+			// A literal unquoted "null" is treated as a null value by the YAML parser.
+			// However, when used as a key, it is treated as the string "null".
 		case "!!merge":
 			if merge != nil {
 				panic("merge node already set")
@@ -115,10 +118,11 @@ func (d *loader) loadMapping(node *yaml.Node, loc dyn.Location) (dyn.Value, erro
 			return dyn.InvalidValue, errorf(loc, "invalid key tag: %v", st)
 		}
 
-		k, err := d.load(key)
+		k := dyn.NewValue(key.Value, []dyn.Location{{
-		if err != nil {
+			File:   d.path,
-			return dyn.InvalidValue, err
+			Line:   key.Line,
-		}
+			Column: key.Column,
+		}})
 
 		v, err := d.load(val)
 		if err != nil {
@@ -173,6 +177,14 @@ func (d *loader) loadMapping(node *yaml.Node, loc dyn.Location) (dyn.Value, erro
 	return dyn.NewValue(out, []dyn.Location{loc}), nil
 }
 
+func newIntValue(i64 int64, loc dyn.Location) dyn.Value {
+	// Use regular int type instead of int64 if possible.
+	if i64 >= math.MinInt32 && i64 <= math.MaxInt32 {
+		return dyn.NewValue(int(i64), []dyn.Location{loc})
+	}
+	return dyn.NewValue(i64, []dyn.Location{loc})
+}
+
 func (d *loader) loadScalar(node *yaml.Node, loc dyn.Location) (dyn.Value, error) {
 	st := node.ShortTag()
 	switch st {
@@ -188,18 +200,44 @@ func (d *loader) loadScalar(node *yaml.Node, loc dyn.Location) (dyn.Value, error
 			return dyn.InvalidValue, errorf(loc, "invalid bool value: %v", node.Value)
 		}
 	case "!!int":
-		i64, err := strconv.ParseInt(node.Value, 10, 64)
+		// Try to parse the an integer value in base 10.
-		if err != nil {
+		// We trim leading zeros to avoid octal parsing of the "0" prefix.
-			return dyn.InvalidValue, errorf(loc, "invalid int value: %v", node.Value)
+		// See "testdata/spec_example_2.19.yml" for background.
+		i64, err := strconv.ParseInt(strings.TrimLeft(node.Value, "0"), 10, 64)
+		if err == nil {
+			return newIntValue(i64, loc), nil
 		}
-		// Use regular int type instead of int64 if possible.
+		// Let the [ParseInt] function figure out the base.
-		if i64 >= math.MinInt32 && i64 <= math.MaxInt32 {
+		i64, err = strconv.ParseInt(node.Value, 0, 64)
-			return dyn.NewValue(int(i64), []dyn.Location{loc}), nil
+		if err == nil {
+			return newIntValue(i64, loc), nil
 		}
-		return dyn.NewValue(i64, []dyn.Location{loc}), nil
+		return dyn.InvalidValue, errorf(loc, "invalid int value: %v", node.Value)
 	case "!!float":
 		f64, err := strconv.ParseFloat(node.Value, 64)
 		if err != nil {
+			// Deal with infinity prefixes.
+			v := strings.ToLower(node.Value)
+			switch {
+			case strings.HasPrefix(v, "+"):
+				v = strings.TrimPrefix(v, "+")
+				f64 = math.Inf(1)
+			case strings.HasPrefix(v, "-"):
+				v = strings.TrimPrefix(v, "-")
+				f64 = math.Inf(-1)
+			default:
+				// No prefix.
+				f64 = math.Inf(1)
+			}
+
+			// Deal with infinity and NaN values.
+			switch v {
+			case ".inf":
+				return dyn.NewValue(f64, []dyn.Location{loc}), nil
+			case ".nan":
+				return dyn.NewValue(math.NaN(), []dyn.Location{loc}), nil
+			}
+
 			return dyn.InvalidValue, errorf(loc, "invalid float value: %v", node.Value)
 		}
 		return dyn.NewValue(f64, []dyn.Location{loc}), nil

libs/dyn/yamlloader/testdata/spec_example_2.1.yml

@@ -0,0 +1,5 @@
+# Example 2.1 Sequence of Scalars (ball players)
+
+- Mark McGwire
+- Sammy Sosa
+- Ken Griffey

libs/dyn/yamlloader/testdata/spec_example_2.10.yml

@@ -0,0 +1,10 @@
+# Example 2.10 Node for “Sammy Sosa” appears twice in this document
+
+---
+hr:
+- Mark McGwire
+# Following node labeled SS
+- &SS Sammy Sosa
+rbi:
+- *SS # Subsequent occurrence
+- Ken Griffey

libs/dyn/yamlloader/testdata/spec_example_2.11.yml

@@ -0,0 +1,10 @@
+# Example 2.11 Mapping between Sequences
+
+? - Detroit Tigers
+  - Chicago cubs
+: - 2001-07-23
+
+? [ New York Yankees,
+    Atlanta Braves ]
+: [ 2001-07-02, 2001-08-12,
+    2001-08-14 ]

libs/dyn/yamlloader/testdata/spec_example_2.12.yml

@@ -0,0 +1,10 @@
+# Example 2.12 Compact Nested Mapping
+
+---
+# Products purchased
+- item    : Super Hoop
+  quantity: 1
+- item    : Basketball
+  quantity: 4
+- item    : Big Shoes
+  quantity: 1

libs/dyn/yamlloader/testdata/spec_example_2.13.yml

@@ -0,0 +1,6 @@
+# Example 2.13 In literals, newlines are preserved
+
+# ASCII Art
+--- |
+  \//||\/||
+  // ||  ||__

libs/dyn/yamlloader/testdata/spec_example_2.14.yml

@@ -0,0 +1,6 @@
+# Example 2.14 In the folded scalars, newlines become spaces
+
+--- >
+  Mark McGwire's
+  year was crippled
+  by a knee injury.

libs/dyn/yamlloader/testdata/spec_example_2.15.yml

@@ -0,0 +1,10 @@
+# Example 2.15 Folded newlines are preserved for “more indented” and blank lines
+
+--- >
+ Sammy Sosa completed another
+ fine season with great stats.
+
+   63 Home Runs
+   0.288 Batting Average
+
+ What a year!

libs/dyn/yamlloader/testdata/spec_example_2.16.yml

@@ -0,0 +1,9 @@
+# Example 2.16 Indentation determines scope
+
+name: Mark McGwire
+accomplishment: >
+  Mark set a major league
+  home run record in 1998.
+stats: |
+  65 Home Runs
+  0.278 Batting Average

libs/dyn/yamlloader/testdata/spec_example_2.17.yml

@@ -0,0 +1,9 @@
+# Example 2.17 Quoted Scalars
+
+unicode: "Sosa did fine.\u263A"
+control: "\b1998\t1999\t2000\n"
+hex esc: "\x0d\x0a is \r\n"
+
+single: '"Howdy!" he cried.'
+quoted: ' # Not a ''comment''.'
+tie-fighter: '|\-*-/|'

libs/dyn/yamlloader/testdata/spec_example_2.18.yml

@@ -0,0 +1,8 @@
+# Example 2.18 Multi-line Flow Scalars
+
+plain:
+  This unquoted scalar
+  spans many lines.
+
+quoted: "So does this
+  quoted scalar.\n"

libs/dyn/yamlloader/testdata/spec_example_2.19.yml

@@ -0,0 +1,15 @@
+# Example 2.19 Integers
+
+canonical: 12345
+decimal: +12345
+octal: 0o14
+hexadecimal: 0xC
+
+# Note: this example is not part of the spec but added for completeness.
+#
+# Octal numbers:
+#   - YAML 1.1: prefix is "0"
+#   - YAML 1.2: prefix is "0o"
+# The "gopkg.in/yaml.v3" package accepts both for backwards compat.
+# We accept only the YAML 1.2 prefix "0o".
+octal11: 012345

libs/dyn/yamlloader/testdata/spec_example_2.2.yml

@@ -0,0 +1,5 @@
+# Example 2.2 Mapping Scalars to Scalars (player statistics)
+
+hr:  65    # Home runs
+avg: 0.278 # Batting average
+rbi: 147   # Runs Batted In

libs/dyn/yamlloader/testdata/spec_example_2.20.yml

@@ -0,0 +1,7 @@
+# Example 2.20 Floating Point
+
+canonical: 1.23015e+3
+exponential: 12.3015e+02
+fixed: 1230.15
+negative infinity: -.inf
+not a number: .nan

libs/dyn/yamlloader/testdata/spec_example_2.21.yml

@@ -0,0 +1,5 @@
+# Example 2.21 Miscellaneous
+
+null:
+booleans: [ true, false ]
+string: '012345'

libs/dyn/yamlloader/testdata/spec_example_2.22.yml

@@ -0,0 +1,6 @@
+# Example 2.22 Timestamps
+
+canonical: 2001-12-15T02:59:43.1Z
+iso8601: 2001-12-14t21:59:43.10-05:00
+spaced: 2001-12-14 21:59:43.10 -5
+date: 2002-12-14

libs/dyn/yamlloader/testdata/spec_example_2.23.yml

@@ -0,0 +1,15 @@
+# Example 2.23 Various Explicit Tags
+
+---
+not-date: !!str 2002-04-28
+
+picture: !!binary |
+ R0lGODlhDAAMAIQAAP//9/X
+ 17unp5WZmZgAAAOfn515eXv
+ Pz7Y6OjuDg4J+fn5OTk6enp
+ 56enmleECcgggoBADs=
+
+application specific tag: !something |
+ The semantics of the tag
+ above may be different for
+ different documents.

libs/dyn/yamlloader/testdata/spec_example_2.24.yml

@@ -0,0 +1,16 @@
+# Example 2.24 Global Tags
+
+%TAG ! tag:clarkevans.com,2002:
+--- !shape
+  # Use the ! handle for presenting
+  # tag:clarkevans.com,2002:circle
+- !circle
+  center: &ORIGIN {x: 73, y: 129}
+  radius: 7
+- !line
+  start: *ORIGIN
+  finish: { x: 89, y: 102 }
+- !label
+  start: *ORIGIN
+  color: 0xFFEEBB
+  text: Pretty vector drawing.

libs/dyn/yamlloader/testdata/spec_example_2.25.yml

@@ -0,0 +1,9 @@
+# Example 2.25 Unordered Sets
+
+# Sets are represented as a
+# Mapping where each key is
+# associated with a null value
+--- !!set
+? Mark McGwire
+? Sammy Sosa
+? Ken Griffey

libs/dyn/yamlloader/testdata/spec_example_2.26.yml

@@ -0,0 +1,9 @@
+# Example 2.26 Ordered Mappings
+
+# Ordered maps are represented as
+# A sequence of mappings, with
+# each mapping having one key
+--- !!omap
+- Mark McGwire: 65
+- Sammy Sosa: 63
+- Ken Griffey: 58

libs/dyn/yamlloader/testdata/spec_example_2.27.yml

@@ -0,0 +1,31 @@
+# Example 2.27 Invoice
+
+--- !<tag:clarkevans.com,2002:invoice>
+invoice: 34843
+date   : 2001-01-23
+bill-to: &id001
+  given  : Chris
+  family : Dumars
+  address:
+    lines: |
+      458 Walkman Dr.
+      Suite #292
+    city    : Royal Oak
+    state   : MI
+    postal  : 48046
+ship-to: *id001
+product:
+- sku         : BL394D
+  quantity    : 4
+  description : Basketball
+  price       : 450.00
+- sku         : BL4438H
+  quantity    : 1
+  description : Super Hoop
+  price       : 2392.00
+tax  : 251.42
+total: 4443.52
+comments:
+  Late afternoon is best.
+  Backup contact is Nancy
+  Billsmer @ 338-4338.

libs/dyn/yamlloader/testdata/spec_example_2.28.yml

@@ -0,0 +1,28 @@
+# Example 2.28 Log File
+
+---
+Time: 2001-11-23 15:01:42 -5
+User: ed
+Warning:
+  This is an error message
+  for the log file
+---
+Time: 2001-11-23 15:02:31 -5
+User: ed
+Warning:
+  A slightly different error
+  message.
+---
+Date: 2001-11-23 15:03:17 -5
+User: ed
+Fatal:
+  Unknown variable "bar"
+Stack:
+- file: TopClass.py
+  line: 23
+  code: |
+    x = MoreObject("345\n")
+- file: MoreClass.py
+  line: 58
+  code: |-
+    foo = bar

libs/dyn/yamlloader/testdata/spec_example_2.3.yml

@@ -0,0 +1,10 @@
+# Example 2.3 Mapping Scalars to Sequences (ball clubs in each league)
+
+american:
+- Boston Red Sox
+- Detroit Tigers
+- New York Yankees
+national:
+- New York Mets
+- Chicago Cubs
+- Atlanta Braves

libs/dyn/yamlloader/testdata/spec_example_2.4.yml

@@ -0,0 +1,10 @@
+# Example 2.4 Sequence of Mappings (players’ statistics)
+
+-
+  name: Mark McGwire
+  hr:   65
+  avg:  0.278
+-
+  name: Sammy Sosa
+  hr:   63
+  avg:  0.288

libs/dyn/yamlloader/testdata/spec_example_2.5.yml

@@ -0,0 +1,5 @@
+# Example 2.5 Sequence of Sequences
+
+- [name        , hr, avg  ]
+- [Mark McGwire, 65, 0.278]
+- [Sammy Sosa  , 63, 0.288]

libs/dyn/yamlloader/testdata/spec_example_2.6.yml

@@ -0,0 +1,7 @@
+# Example 2.6 Mapping of Mappings
+
+Mark McGwire: {hr: 65, avg: 0.278}
+Sammy Sosa: {
+    hr: 63,
+    avg: 0.288,
+ }

libs/dyn/yamlloader/testdata/spec_example_2.7.yml

@@ -0,0 +1,12 @@
+# Example 2.7 Two Documents in a Stream (each with a leading comment)
+
+# Ranking of 1998 home runs
+---
+- Mark McGwire
+- Sammy Sosa
+- Ken Griffey
+
+# Team ranking
+---
+- Chicago Cubs
+- St Louis Cardinals

libs/dyn/yamlloader/testdata/spec_example_2.8.yml

@@ -0,0 +1,12 @@
+# Example 2.8 Play by Play Feed from a Game
+
+---
+time: 20:03:20
+player: Sammy Sosa
+action: strike (miss)
+...
+---
+time: 20:03:47
+player: Sammy Sosa
+action: grand slam
+...

libs/dyn/yamlloader/testdata/spec_example_2.9.yml

@@ -0,0 +1,10 @@
+# Example 2.9 Single Document with Two Comments
+
+---
+hr: # 1998 hr ranking
+- Mark McGwire
+- Sammy Sosa
+# 1998 rbi ranking
+rbi:
+- Sammy Sosa
+- Ken Griffey

libs/dyn/yamlloader/yaml_spec_test.go

@@ -0,0 +1,821 @@
+package yamlloader_test
+
+import (
+	"bytes"
+	"math"
+	"os"
+	"testing"
+
+	"github.com/databricks/cli/libs/dyn"
+	assert "github.com/databricks/cli/libs/dyn/dynassert"
+	"github.com/databricks/cli/libs/dyn/yamlloader"
+	"github.com/stretchr/testify/require"
+)
+
+const NL = "\n"
+
+func loadExample(t *testing.T, file string) dyn.Value {
+	input, err := os.ReadFile(file)
+	require.NoError(t, err)
+	self, err := yamlloader.LoadYAML(file, bytes.NewBuffer(input))
+	require.NoError(t, err)
+	return self
+}
+
+func TestYAMLSpecExample_2_1(t *testing.T) {
+	file := "testdata/spec_example_2.1.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		[]dyn.Value{
+			dyn.NewValue("Mark McGwire", []dyn.Location{{File: file, Line: 3, Column: 3}}),
+			dyn.NewValue("Sammy Sosa", []dyn.Location{{File: file, Line: 4, Column: 3}}),
+			dyn.NewValue("Ken Griffey", []dyn.Location{{File: file, Line: 5, Column: 3}}),
+		},
+		[]dyn.Location{{File: file, Line: 3, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_2(t *testing.T) {
+	file := "testdata/spec_example_2.2.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"hr":  dyn.NewValue(65, []dyn.Location{{File: file, Line: 3, Column: 6}}),
+			"avg": dyn.NewValue(0.278, []dyn.Location{{File: file, Line: 4, Column: 6}}),
+			"rbi": dyn.NewValue(147, []dyn.Location{{File: file, Line: 5, Column: 6}}),
+		},
+		[]dyn.Location{{File: file, Line: 3, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_3(t *testing.T) {
+	file := "testdata/spec_example_2.3.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"american": dyn.NewValue(
+				[]dyn.Value{
+					dyn.NewValue("Boston Red Sox", []dyn.Location{{File: file, Line: 4, Column: 3}}),
+					dyn.NewValue("Detroit Tigers", []dyn.Location{{File: file, Line: 5, Column: 3}}),
+					dyn.NewValue("New York Yankees", []dyn.Location{{File: file, Line: 6, Column: 3}}),
+				},
+				[]dyn.Location{{File: file, Line: 4, Column: 1}},
+			),
+			"national": dyn.NewValue(
+				[]dyn.Value{
+					dyn.NewValue("New York Mets", []dyn.Location{{File: file, Line: 8, Column: 3}}),
+					dyn.NewValue("Chicago Cubs", []dyn.Location{{File: file, Line: 9, Column: 3}}),
+					dyn.NewValue("Atlanta Braves", []dyn.Location{{File: file, Line: 10, Column: 3}}),
+				},
+				[]dyn.Location{{File: file, Line: 8, Column: 1}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 3, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_4(t *testing.T) {
+	file := "testdata/spec_example_2.4.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		[]dyn.Value{
+			dyn.NewValue(
+				map[string]dyn.Value{
+					"name": dyn.NewValue("Mark McGwire", []dyn.Location{{File: file, Line: 4, Column: 9}}),
+					"hr":   dyn.NewValue(65, []dyn.Location{{File: file, Line: 5, Column: 9}}),
+					"avg":  dyn.NewValue(0.278, []dyn.Location{{File: file, Line: 6, Column: 9}}),
+				},
+				[]dyn.Location{{File: file, Line: 4, Column: 3}},
+			),
+			dyn.NewValue(
+				map[string]dyn.Value{
+					"name": dyn.NewValue("Sammy Sosa", []dyn.Location{{File: file, Line: 8, Column: 9}}),
+					"hr":   dyn.NewValue(63, []dyn.Location{{File: file, Line: 9, Column: 9}}),
+					"avg":  dyn.NewValue(0.288, []dyn.Location{{File: file, Line: 10, Column: 9}}),
+				},
+				[]dyn.Location{{File: file, Line: 8, Column: 3}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 3, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_5(t *testing.T) {
+	file := "testdata/spec_example_2.5.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		[]dyn.Value{
+			dyn.NewValue(
+				[]dyn.Value{
+					dyn.NewValue("name", []dyn.Location{{File: file, Line: 3, Column: 4}}),
+					dyn.NewValue("hr", []dyn.Location{{File: file, Line: 3, Column: 18}}),
+					dyn.NewValue("avg", []dyn.Location{{File: file, Line: 3, Column: 22}}),
+				},
+				[]dyn.Location{{File: file, Line: 3, Column: 3}},
+			),
+			dyn.NewValue(
+				[]dyn.Value{
+					dyn.NewValue("Mark McGwire", []dyn.Location{{File: file, Line: 4, Column: 4}}),
+					dyn.NewValue(65, []dyn.Location{{File: file, Line: 4, Column: 18}}),
+					dyn.NewValue(0.278, []dyn.Location{{File: file, Line: 4, Column: 22}}),
+				},
+				[]dyn.Location{{File: file, Line: 4, Column: 3}},
+			),
+			dyn.NewValue(
+				[]dyn.Value{
+					dyn.NewValue("Sammy Sosa", []dyn.Location{{File: file, Line: 5, Column: 4}}),
+					dyn.NewValue(63, []dyn.Location{{File: file, Line: 5, Column: 18}}),
+					dyn.NewValue(0.288, []dyn.Location{{File: file, Line: 5, Column: 22}}),
+				},
+				[]dyn.Location{{File: file, Line: 5, Column: 3}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 3, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_6(t *testing.T) {
+	file := "testdata/spec_example_2.6.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"Mark McGwire": dyn.NewValue(
+				map[string]dyn.Value{
+					"hr":  dyn.NewValue(65, []dyn.Location{{File: file, Line: 3, Column: 20}}),
+					"avg": dyn.NewValue(0.278, []dyn.Location{{File: file, Line: 3, Column: 29}}),
+				},
+				[]dyn.Location{{File: file, Line: 3, Column: 15}},
+			),
+			"Sammy Sosa": dyn.NewValue(
+				map[string]dyn.Value{
+					"hr":  dyn.NewValue(63, []dyn.Location{{File: file, Line: 5, Column: 9}}),
+					"avg": dyn.NewValue(0.288, []dyn.Location{{File: file, Line: 6, Column: 10}}),
+				},
+				[]dyn.Location{{File: file, Line: 4, Column: 13}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 3, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_7(t *testing.T) {
+	file := "testdata/spec_example_2.7.yml"
+	self := loadExample(t, file)
+
+	// Note: we do not support multiple documents in a single YAML file.
+
+	assert.Equal(t, dyn.NewValue(
+		[]dyn.Value{
+			dyn.NewValue(
+				"Mark McGwire",
+				[]dyn.Location{{File: file, Line: 5, Column: 3}},
+			),
+			dyn.NewValue(
+				"Sammy Sosa",
+				[]dyn.Location{{File: file, Line: 6, Column: 3}},
+			),
+			dyn.NewValue(
+				"Ken Griffey",
+				[]dyn.Location{{File: file, Line: 7, Column: 3}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 5, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_8(t *testing.T) {
+	file := "testdata/spec_example_2.8.yml"
+	self := loadExample(t, file)
+
+	// Note: we do not support multiple documents in a single YAML file.
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"time":   dyn.NewValue("20:03:20", []dyn.Location{{File: file, Line: 4, Column: 7}}),
+			"player": dyn.NewValue("Sammy Sosa", []dyn.Location{{File: file, Line: 5, Column: 9}}),
+			"action": dyn.NewValue("strike (miss)", []dyn.Location{{File: file, Line: 6, Column: 9}}),
+		},
+		[]dyn.Location{{File: file, Line: 4, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_9(t *testing.T) {
+	file := "testdata/spec_example_2.9.yml"
+	self := loadExample(t, file)
+
+	// Note: we do not support multiple documents in a single YAML file.
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"hr": dyn.NewValue(
+				[]dyn.Value{
+					dyn.NewValue("Mark McGwire", []dyn.Location{{File: file, Line: 5, Column: 3}}),
+					dyn.NewValue("Sammy Sosa", []dyn.Location{{File: file, Line: 6, Column: 3}}),
+				},
+				[]dyn.Location{{File: file, Line: 5, Column: 1}},
+			),
+			"rbi": dyn.NewValue(
+				[]dyn.Value{
+					dyn.NewValue("Sammy Sosa", []dyn.Location{{File: file, Line: 9, Column: 3}}),
+					dyn.NewValue("Ken Griffey", []dyn.Location{{File: file, Line: 10, Column: 3}}),
+				},
+				[]dyn.Location{{File: file, Line: 9, Column: 1}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 4, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_10(t *testing.T) {
+	file := "testdata/spec_example_2.10.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"hr": dyn.NewValue(
+				[]dyn.Value{
+					dyn.NewValue("Mark McGwire", []dyn.Location{{File: file, Line: 5, Column: 3}}),
+					dyn.NewValue("Sammy Sosa", []dyn.Location{{File: file, Line: 7, Column: 3}}),
+				},
+				[]dyn.Location{{File: file, Line: 5, Column: 1}},
+			),
+			"rbi": dyn.NewValue(
+				[]dyn.Value{
+					// The location for an anchored value refers to the anchor, not the reference.
+					// This is the same location as the anchor that appears in the "hr" mapping.
+					dyn.NewValue("Sammy Sosa", []dyn.Location{{File: file, Line: 7, Column: 3}}),
+					dyn.NewValue("Ken Griffey", []dyn.Location{{File: file, Line: 10, Column: 3}}),
+				},
+				[]dyn.Location{{File: file, Line: 9, Column: 1}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 4, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_11(t *testing.T) {
+	file := "testdata/spec_example_2.11.yml"
+	input, err := os.ReadFile(file)
+	require.NoError(t, err)
+
+	// Note: non-string mapping keys are not supported by "gopkg.in/yaml.v3".
+	_, err = yamlloader.LoadYAML(file, bytes.NewBuffer(input))
+	assert.ErrorContains(t, err, `: key is not a scalar`)
+}
+
+func TestYAMLSpecExample_2_12(t *testing.T) {
+	file := "testdata/spec_example_2.12.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		[]dyn.Value{
+			dyn.NewValue(
+				map[string]dyn.Value{
+					"item":     dyn.NewValue("Super Hoop", []dyn.Location{{File: file, Line: 5, Column: 13}}),
+					"quantity": dyn.NewValue(1, []dyn.Location{{File: file, Line: 6, Column: 13}}),
+				},
+				[]dyn.Location{{File: file, Line: 5, Column: 3}},
+			),
+			dyn.NewValue(
+				map[string]dyn.Value{
+					"item":     dyn.NewValue("Basketball", []dyn.Location{{File: file, Line: 7, Column: 13}}),
+					"quantity": dyn.NewValue(4, []dyn.Location{{File: file, Line: 8, Column: 13}}),
+				},
+				[]dyn.Location{{File: file, Line: 7, Column: 3}},
+			),
+			dyn.NewValue(
+				map[string]dyn.Value{
+					"item":     dyn.NewValue("Big Shoes", []dyn.Location{{File: file, Line: 9, Column: 13}}),
+					"quantity": dyn.NewValue(1, []dyn.Location{{File: file, Line: 10, Column: 13}}),
+				},
+				[]dyn.Location{{File: file, Line: 9, Column: 3}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 5, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_13(t *testing.T) {
+	file := "testdata/spec_example_2.13.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		``+
+			`\//||\/||`+NL+
+			"// ||  ||__"+NL,
+		[]dyn.Location{{File: file, Line: 4, Column: 5}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_14(t *testing.T) {
+	file := "testdata/spec_example_2.14.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		`Mark McGwire's year was crippled by a knee injury.`+NL,
+		[]dyn.Location{{File: file, Line: 3, Column: 5}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_15(t *testing.T) {
+	file := "testdata/spec_example_2.15.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		``+
+			`Sammy Sosa completed another fine season with great stats.`+NL+
+			NL+
+			`  63 Home Runs`+NL+
+			`  0.288 Batting Average`+NL+
+			NL+
+			`What a year!`+NL,
+		[]dyn.Location{{File: file, Line: 3, Column: 5}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_16(t *testing.T) {
+	file := "testdata/spec_example_2.16.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"name": dyn.NewValue(
+				"Mark McGwire",
+				[]dyn.Location{{File: file, Line: 3, Column: 7}},
+			),
+			"accomplishment": dyn.NewValue(
+				`Mark set a major league home run record in 1998.`+NL,
+				[]dyn.Location{{File: file, Line: 4, Column: 17}},
+			),
+			"stats": dyn.NewValue(
+				``+
+					`65 Home Runs`+NL+
+					`0.278 Batting Average`+NL,
+				[]dyn.Location{{File: file, Line: 7, Column: 8}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 3, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_17(t *testing.T) {
+	file := "testdata/spec_example_2.17.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"unicode": dyn.NewValue(
+				`Sosa did fine.`+"\u263A",
+				[]dyn.Location{{File: file, Line: 3, Column: 10}},
+			),
+			"control": dyn.NewValue(
+				"\b1998\t1999\t2000\n",
+				[]dyn.Location{{File: file, Line: 4, Column: 10}},
+			),
+			"hex esc": dyn.NewValue(
+				"\x0d\x0a is \r\n",
+				[]dyn.Location{{File: file, Line: 5, Column: 10}},
+			),
+			"single": dyn.NewValue(
+				`"Howdy!" he cried.`,
+				[]dyn.Location{{File: file, Line: 7, Column: 9}},
+			),
+			"quoted": dyn.NewValue(
+				` # Not a 'comment'.`,
+				[]dyn.Location{{File: file, Line: 8, Column: 9}},
+			),
+			"tie-fighter": dyn.NewValue(
+				`|\-*-/|`,
+				[]dyn.Location{{File: file, Line: 9, Column: 14}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 3, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_18(t *testing.T) {
+	file := "testdata/spec_example_2.18.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"plain": dyn.NewValue(
+				`This unquoted scalar spans many lines.`,
+				[]dyn.Location{{File: file, Line: 4, Column: 3}},
+			),
+			"quoted": dyn.NewValue(
+				`So does this quoted scalar.`+NL,
+				[]dyn.Location{{File: file, Line: 7, Column: 9}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 3, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_19(t *testing.T) {
+	file := "testdata/spec_example_2.19.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"canonical": dyn.NewValue(
+				12345,
+				[]dyn.Location{{File: file, Line: 3, Column: 12}},
+			),
+			"decimal": dyn.NewValue(
+				12345,
+				[]dyn.Location{{File: file, Line: 4, Column: 10}},
+			),
+			"octal": dyn.NewValue(
+				12,
+				[]dyn.Location{{File: file, Line: 5, Column: 8}},
+			),
+			"hexadecimal": dyn.NewValue(
+				12,
+				[]dyn.Location{{File: file, Line: 6, Column: 14}},
+			),
+			"octal11": dyn.NewValue(
+				12345,
+				[]dyn.Location{{File: file, Line: 15, Column: 10}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 3, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_20(t *testing.T) {
+	file := "testdata/spec_example_2.20.yml"
+	self := loadExample(t, file)
+
+	// Equality assertion doesn't work with NaNs.
+	// See https://github.com/stretchr/testify/issues/624.
+	//
+	// Remove the NaN entry.
+	self, _ = dyn.Walk(self, func(p dyn.Path, v dyn.Value) (dyn.Value, error) {
+		if f, ok := v.AsFloat(); ok && math.IsNaN(f) {
+			return dyn.InvalidValue, dyn.ErrDrop
+		}
+		return v, nil
+	})
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"canonical": dyn.NewValue(
+				1230.15,
+				[]dyn.Location{{File: file, Line: 3, Column: 12}},
+			),
+			"exponential": dyn.NewValue(
+				1230.15,
+				[]dyn.Location{{File: file, Line: 4, Column: 14}},
+			),
+			"fixed": dyn.NewValue(
+				1230.15,
+				[]dyn.Location{{File: file, Line: 5, Column: 8}},
+			),
+			"negative infinity": dyn.NewValue(
+				math.Inf(-1),
+				[]dyn.Location{{File: file, Line: 6, Column: 20}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 3, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_21(t *testing.T) {
+	file := "testdata/spec_example_2.21.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"null": dyn.NewValue(
+				nil,
+				[]dyn.Location{{File: file, Line: 3, Column: 6}},
+			),
+			"booleans": dyn.NewValue(
+				[]dyn.Value{
+					dyn.NewValue(true, []dyn.Location{{File: file, Line: 4, Column: 13}}),
+					dyn.NewValue(false, []dyn.Location{{File: file, Line: 4, Column: 19}}),
+				},
+				[]dyn.Location{{File: file, Line: 4, Column: 11}},
+			),
+			"string": dyn.NewValue(
+				"012345",
+				[]dyn.Location{{File: file, Line: 5, Column: 9}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 3, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_22(t *testing.T) {
+	file := "testdata/spec_example_2.22.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"canonical": dyn.NewValue(
+				dyn.MustTime("2001-12-15T02:59:43.1Z"),
+				[]dyn.Location{{File: file, Line: 3, Column: 12}},
+			),
+			"iso8601": dyn.NewValue(
+				dyn.MustTime("2001-12-14t21:59:43.10-05:00"),
+				[]dyn.Location{{File: file, Line: 4, Column: 10}},
+			),
+			"spaced": dyn.NewValue(
+				// This is parsed as a string, not a timestamp,
+				// both by "gopkg.in/yaml.v3" and by our implementation.
+				"2001-12-14 21:59:43.10 -5",
+				[]dyn.Location{{File: file, Line: 5, Column: 9}},
+			),
+			"date": dyn.NewValue(
+				dyn.MustTime("2002-12-14"),
+				[]dyn.Location{{File: file, Line: 6, Column: 7}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 3, Column: 1}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_23(t *testing.T) {
+	file := "testdata/spec_example_2.23.yml"
+	input, err := os.ReadFile(file)
+	require.NoError(t, err)
+
+	// Note: the !!binary tag is not supported by us.
+
+	_, err = yamlloader.LoadYAML(file, bytes.NewBuffer(input))
+	assert.ErrorContains(t, err, `: unknown tag: !!binary`)
+}
+
+func TestYAMLSpecExample_2_24(t *testing.T) {
+	file := "testdata/spec_example_2.24.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		[]dyn.Value{
+			dyn.NewValue(
+				map[string]dyn.Value{
+					"center": dyn.NewValue(
+						map[string]dyn.Value{
+							"x": dyn.NewValue(73, []dyn.Location{{File: file, Line: 8, Column: 23}}),
+							"y": dyn.NewValue(129, []dyn.Location{{File: file, Line: 8, Column: 30}}),
+						},
+						[]dyn.Location{{File: file, Line: 8, Column: 11}},
+					),
+					"radius": dyn.NewValue(7, []dyn.Location{{File: file, Line: 9, Column: 11}}),
+				},
+				[]dyn.Location{{File: file, Line: 7, Column: 3}},
+			),
+			dyn.NewValue(
+				map[string]dyn.Value{
+					"start": dyn.NewValue(
+						map[string]dyn.Value{
+							"x": dyn.NewValue(73, []dyn.Location{{File: file, Line: 8, Column: 23}}),
+							"y": dyn.NewValue(129, []dyn.Location{{File: file, Line: 8, Column: 30}}),
+						},
+						[]dyn.Location{{File: file, Line: 8, Column: 11}},
+					),
+					"finish": dyn.NewValue(
+						map[string]dyn.Value{
+							"x": dyn.NewValue(89, []dyn.Location{{File: file, Line: 12, Column: 16}}),
+							"y": dyn.NewValue(102, []dyn.Location{{File: file, Line: 12, Column: 23}}),
+						},
+						[]dyn.Location{{File: file, Line: 12, Column: 11}},
+					),
+				},
+				[]dyn.Location{{File: file, Line: 10, Column: 3}},
+			),
+			dyn.NewValue(
+				map[string]dyn.Value{
+					"start": dyn.NewValue(
+						map[string]dyn.Value{
+							"x": dyn.NewValue(73, []dyn.Location{{File: file, Line: 8, Column: 23}}),
+							"y": dyn.NewValue(129, []dyn.Location{{File: file, Line: 8, Column: 30}}),
+						},
+						[]dyn.Location{{File: file, Line: 8, Column: 11}},
+					),
+					"color": dyn.NewValue(16772795, []dyn.Location{{File: file, Line: 15, Column: 10}}),
+					"text":  dyn.NewValue("Pretty vector drawing.", []dyn.Location{{File: file, Line: 16, Column: 9}}),
+				},
+				[]dyn.Location{{File: file, Line: 13, Column: 3}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 4, Column: 5}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_25(t *testing.T) {
+	file := "testdata/spec_example_2.25.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"Mark McGwire": dyn.NewValue(nil, []dyn.Location{{File: file, Line: 8, Column: 1}}),
+			"Sammy Sosa":   dyn.NewValue(nil, []dyn.Location{{File: file, Line: 9, Column: 1}}),
+			"Ken Griffey":  dyn.NewValue(nil, []dyn.Location{{File: file, Line: 10, Column: 1}}),
+		},
+		[]dyn.Location{{File: file, Line: 6, Column: 5}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_26(t *testing.T) {
+	file := "testdata/spec_example_2.26.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		[]dyn.Value{
+			dyn.NewValue(
+				map[string]dyn.Value{
+					"Mark McGwire": dyn.NewValue(65, []dyn.Location{{File: file, Line: 7, Column: 17}}),
+				},
+				[]dyn.Location{{File: file, Line: 7, Column: 3}},
+			),
+			dyn.NewValue(
+				map[string]dyn.Value{
+					"Sammy Sosa": dyn.NewValue(63, []dyn.Location{{File: file, Line: 8, Column: 15}}),
+				},
+				[]dyn.Location{{File: file, Line: 8, Column: 3}},
+			),
+			dyn.NewValue(
+				map[string]dyn.Value{
+					"Ken Griffey": dyn.NewValue(58, []dyn.Location{{File: file, Line: 9, Column: 16}}),
+				},
+				[]dyn.Location{{File: file, Line: 9, Column: 3}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 6, Column: 5}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_27(t *testing.T) {
+	file := "testdata/spec_example_2.27.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"invoice": dyn.NewValue(
+				34843,
+				[]dyn.Location{{File: file, Line: 4, Column: 10}},
+			),
+			"date": dyn.NewValue(
+				dyn.MustTime("2001-01-23"),
+				[]dyn.Location{{File: file, Line: 5, Column: 10}},
+			),
+			"bill-to": dyn.NewValue(
+				map[string]dyn.Value{
+					"given": dyn.NewValue(
+						"Chris",
+						[]dyn.Location{{File: file, Line: 7, Column: 12}},
+					),
+					"family": dyn.NewValue(
+						"Dumars",
+						[]dyn.Location{{File: file, Line: 8, Column: 12}},
+					),
+					"address": dyn.NewValue(
+						map[string]dyn.Value{
+							"lines": dyn.NewValue(
+								"458 Walkman Dr.\nSuite #292\n",
+								[]dyn.Location{{File: file, Line: 10, Column: 12}},
+							),
+							"city": dyn.NewValue(
+								"Royal Oak",
+								[]dyn.Location{{File: file, Line: 13, Column: 15}},
+							),
+							"state": dyn.NewValue(
+								"MI",
+								[]dyn.Location{{File: file, Line: 14, Column: 15}},
+							),
+							"postal": dyn.NewValue(
+								48046,
+								[]dyn.Location{{File: file, Line: 15, Column: 15}},
+							),
+						},
+						[]dyn.Location{{File: file, Line: 10, Column: 5}},
+					),
+				},
+				[]dyn.Location{{File: file, Line: 6, Column: 10}},
+			),
+			"ship-to": dyn.NewValue(
+				map[string]dyn.Value{
+					"given": dyn.NewValue(
+						"Chris",
+						[]dyn.Location{{File: file, Line: 7, Column: 12}},
+					),
+					"family": dyn.NewValue(
+						"Dumars",
+						[]dyn.Location{{File: file, Line: 8, Column: 12}},
+					),
+					"address": dyn.NewValue(
+						map[string]dyn.Value{
+							"lines": dyn.NewValue(
+								"458 Walkman Dr.\nSuite #292\n",
+								[]dyn.Location{{File: file, Line: 10, Column: 12}},
+							),
+							"city": dyn.NewValue(
+								"Royal Oak",
+								[]dyn.Location{{File: file, Line: 13, Column: 15}},
+							),
+							"state": dyn.NewValue(
+								"MI",
+								[]dyn.Location{{File: file, Line: 14, Column: 15}},
+							),
+							"postal": dyn.NewValue(
+								48046,
+								[]dyn.Location{{File: file, Line: 15, Column: 15}},
+							),
+						},
+						[]dyn.Location{{File: file, Line: 10, Column: 5}},
+					),
+				},
+				[]dyn.Location{{File: file, Line: 6, Column: 10}},
+			),
+			"product": dyn.NewValue(
+				[]dyn.Value{
+					dyn.NewValue(
+						map[string]dyn.Value{
+							"sku": dyn.NewValue(
+								"BL394D",
+								[]dyn.Location{{File: file, Line: 18, Column: 17}},
+							),
+							"quantity": dyn.NewValue(
+								4,
+								[]dyn.Location{{File: file, Line: 19, Column: 17}},
+							),
+							"description": dyn.NewValue(
+								"Basketball",
+								[]dyn.Location{{File: file, Line: 20, Column: 17}},
+							),
+							"price": dyn.NewValue(
+								450.0,
+								[]dyn.Location{{File: file, Line: 21, Column: 17}},
+							),
+						},
+						[]dyn.Location{{File: file, Line: 18, Column: 3}},
+					), dyn.NewValue(
+						map[string]dyn.Value{
+							"sku": dyn.NewValue(
+								"BL4438H",
+								[]dyn.Location{{File: file, Line: 22, Column: 17}},
+							),
+							"quantity": dyn.NewValue(
+								1,
+								[]dyn.Location{{File: file, Line: 23, Column: 17}},
+							),
+							"description": dyn.NewValue(
+								"Super Hoop",
+								[]dyn.Location{{File: file, Line: 24, Column: 17}},
+							),
+							"price": dyn.NewValue(
+								2392.0,
+								[]dyn.Location{{File: file, Line: 25, Column: 17}},
+							),
+						},
+						[]dyn.Location{{File: file, Line: 22, Column: 3}},
+					)},
+				[]dyn.Location{{File: file, Line: 18, Column: 1}},
+			),
+			"tax": dyn.NewValue(
+				251.42,
+				[]dyn.Location{{File: file, Line: 26, Column: 8}},
+			),
+			"total": dyn.NewValue(
+				4443.52,
+				[]dyn.Location{{File: file, Line: 27, Column: 8}},
+			),
+			"comments": dyn.NewValue(
+				"Late afternoon is best. Backup contact is Nancy Billsmer @ 338-4338.",
+				[]dyn.Location{{File: file, Line: 29, Column: 3}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 3, Column: 5}},
+	), self)
+}
+
+func TestYAMLSpecExample_2_28(t *testing.T) {
+	file := "testdata/spec_example_2.28.yml"
+	self := loadExample(t, file)
+
+	assert.Equal(t, dyn.NewValue(
+		map[string]dyn.Value{
+			"Time": dyn.NewValue(
+				"2001-11-23 15:01:42 -5",
+				[]dyn.Location{{File: file, Line: 4, Column: 7}},
+			),
+			"User": dyn.NewValue(
+				"ed",
+				[]dyn.Location{{File: file, Line: 5, Column: 7}},
+			),
+			"Warning": dyn.NewValue(
+				"This is an error message for the log file",
+				[]dyn.Location{{File: file, Line: 7, Column: 3}},
+			),
+		},
+		[]dyn.Location{{File: file, Line: 4, Column: 1}},
+	), self)
+}