diff --git a/element.go b/element.go
index ba76aec..e4da48f 100644
--- a/element.go
+++ b/element.go
@@ -5,6 +5,7 @@ import (
 	"encoding/xml"
 	"fmt"
 	"io"
+	"maps"
 	"slices"
 	"strings"
 )
@@ -171,7 +172,7 @@ func (e *element) writeGoType(w io.Writer, options *generateOptions, indentPrefi
 	if e.root && options.namedRoot {
 		fmt.Fprintf(w, "%s\tXMLName xml.Name `xml:\"%s\"`\n", indentPrefix, e.name.Local)
 	}
-	for _, exportedAttrName := range sortedKeys(attrValuesByExportedName) {
+	for _, exportedAttrName := range slices.Sorted(maps.Keys(attrValuesByExportedName)) {
 		attrValue := attrValuesByExportedName[exportedAttrName]
 		fmt.Fprintf(w, "%s\t%s %s `xml:\"%s,attr\"`\n", indentPrefix, exportedAttrName, attrValue.goType(options), attrValue.name.Local)
 	}
@@ -185,7 +186,7 @@ func (e *element) writeGoType(w io.Writer, options *generateOptions, indentPrefi
 		fmt.Fprintf(w, "%s\t%s string `xml:\",chardata\"`\n", indentPrefix, fieldName)
 	}
 
-	childElements := mapValues(e.childElements)
+	childElements := slices.Collect(maps.Values(e.childElements))
 	if options.preserveOrder {
 		slices.SortFunc(childElements, func(a, b *element) int {
 			return e.childOrder[a.name] - e.childOrder[b.name]
diff --git a/generator.go b/generator.go
index 4125ef8..85072a2 100644
--- a/generator.go
+++ b/generator.go
@@ -7,9 +7,9 @@ import (
 	"go/format"
 	"io"
 	"io/fs"
+	"maps"
 	"os"
 	"slices"
-	"sort"
 	"strings"
 
 	"golang.org/x/net/html/charset"
@@ -306,9 +306,9 @@ func (g *Generator) Generate() ([]byte, error) {
 			options.simpleTypes[name] = struct{}{}
 			delete(options.namedTypes, name)
 		}
-		typeElements = mapValues(options.namedTypes)
+		typeElements = slices.Collect(maps.Values(options.namedTypes))
 	} else {
-		typeElements = mapValues(g.typeElements)
+		typeElements = slices.Collect(maps.Values(g.typeElements))
 	}
 
 	if options.preserveOrder {
@@ -365,9 +365,7 @@ func (g *Generator) Generate() ([]byte, error) {
 			}
 		default:
 			fmt.Fprintf(sourceBuilder, "import (\n")
-			importPackageNames := mapKeys(options.importPackageNames)
-			sort.Strings(importPackageNames)
-			for _, importPackageName := range importPackageNames {
+			for _, importPackageName := range slices.Sorted(maps.Keys(options.importPackageNames)) {
 				fmt.Fprintf(sourceBuilder, "\t%q\n", importPackageName)
 			}
 			fmt.Fprintf(sourceBuilder, ")\n")
diff --git a/xmlstruct.go b/xmlstruct.go
index 4654b39..141c447 100644
--- a/xmlstruct.go
+++ b/xmlstruct.go
@@ -2,10 +2,8 @@
 package xmlstruct
 
 import (
-	"cmp"
 	"encoding/xml"
 	"regexp"
-	"slices"
 	"strings"
 	"unicode"
 )
@@ -31,69 +29,9 @@ const (
 )
 
 var (
-	// TitleFirstRuneExportNameFunc returns name.Local with the initial rune
-	// capitalized.
-	TitleFirstRuneExportNameFunc = func(name xml.Name) string {
-		runes := []rune(name.Local)
-		runes[0] = unicode.ToUpper(runes[0])
-		return string(runes)
-	}
-
 	kebabOrSnakeCaseWordBoundaryRx = regexp.MustCompile(`[-_]+\pL`)
 	nonIdentifierRuneRx            = regexp.MustCompile(`[^\pL\pN]`)
 
-	// DefaultExportNameFunc returns name.Local with kebab- and snakecase words
-	// converted to UpperCamelCase and any Id suffix converted to ID.
-	DefaultExportNameFunc = func(name xml.Name) string {
-		localName := kebabOrSnakeCaseWordBoundaryRx.ReplaceAllStringFunc(name.Local, func(s string) string {
-			return strings.ToUpper(s[len(s)-1:])
-		})
-		localName = nonIdentifierRuneRx.ReplaceAllLiteralString(localName, "_")
-		runes := []rune(localName)
-		runes[0] = unicode.ToUpper(runes[0])
-		if len(runes) > 1 && runes[len(runes)-2] == 'I' && runes[len(runes)-1] == 'd' {
-			runes[len(runes)-1] = 'D'
-		}
-		return string(runes)
-	}
-
-	// DefaultUnexportNameFunc returns name.Local with kebab- and snakecase words
-	// converted to lowerCamelCase
-	// Any ID prefix is converted to id, and any Id suffix converted to ID.
-	DefaultUnexportNameFunc = func(name xml.Name) string {
-		localName := kebabOrSnakeCaseWordBoundaryRx.ReplaceAllStringFunc(name.Local, func(s string) string {
-			return strings.ToUpper(s[len(s)-1:])
-		})
-		localName = nonIdentifierRuneRx.ReplaceAllLiteralString(localName, "_")
-		runes := []rune(localName)
-		runes[0] = unicode.ToLower(runes[0])
-		if len(runes) > 1 {
-			if runes[len(runes)-2] == 'I' && runes[len(runes)-1] == 'd' {
-				runes[len(runes)-1] = 'D'
-			}
-			if runes[0] == 'i' && runes[1] == 'D' {
-				runes[1] = 'd'
-			}
-		}
-		return string(runes)
-	}
-)
-
-var (
-	// IgnoreNamespaceNameFunc returns name with name.Space cleared. The same
-	// local name in different namespaces will be treated as identical names.
-	IgnoreNamespaceNameFunc = func(name xml.Name) xml.Name {
-		return xml.Name{
-			Local: name.Local,
-		}
-	}
-
-	// The IdentityNameFunc returns name unchanged. The same local name in
-	// different namespaces will be treated as distinct names.
-	IdentityNameFunc = func(name xml.Name) xml.Name {
-		return name
-	}
-
 	DefaultNameFunc = IgnoreNamespaceNameFunc
 )
 
@@ -134,25 +72,60 @@ type generateOptions struct {
 	emptyElements                bool
 }
 
-func mapKeys[M ~map[K]V, K comparable, V any](m M) []K {
-	keys := make([]K, 0, len(m))
-	for k := range m {
-		keys = append(keys, k)
+// DefaultExportNameFunc returns name.Local with kebab- and snake_case words
+// converted to UpperCamelCase and any Id suffix converted to ID.
+func DefaultExportNameFunc(name xml.Name) string {
+	localName := kebabOrSnakeCaseWordBoundaryRx.ReplaceAllStringFunc(name.Local, func(s string) string {
+		return strings.ToUpper(s[len(s)-1:])
+	})
+	localName = nonIdentifierRuneRx.ReplaceAllLiteralString(localName, "_")
+	runes := []rune(localName)
+	runes[0] = unicode.ToUpper(runes[0])
+	if len(runes) > 1 && runes[len(runes)-2] == 'I' && runes[len(runes)-1] == 'd' {
+		runes[len(runes)-1] = 'D'
+	}
+	return string(runes)
+}
+
+// DefaultUnexportNameFunc returns name.Local with kebab- and snake_case words
+// converted to lowerCamelCase. Any ID prefix is converted to id, and any Id
+// suffix converted to ID.
+func DefaultUnexportNameFunc(name xml.Name) string {
+	localName := kebabOrSnakeCaseWordBoundaryRx.ReplaceAllStringFunc(name.Local, func(s string) string {
+		return strings.ToUpper(s[len(s)-1:])
+	})
+	localName = nonIdentifierRuneRx.ReplaceAllLiteralString(localName, "_")
+	runes := []rune(localName)
+	runes[0] = unicode.ToLower(runes[0])
+	if len(runes) > 1 {
+		if runes[len(runes)-2] == 'I' && runes[len(runes)-1] == 'd' {
+			runes[len(runes)-1] = 'D'
+		}
+		if runes[0] == 'i' && runes[1] == 'D' {
+			runes[1] = 'd'
+		}
 	}
-	return keys
+	return string(runes)
 }
 
-func mapValues[M ~map[K]V, K comparable, V any](m M) []V {
-	values := make([]V, 0, len(m))
-	for _, v := range m {
-		values = append(values, v)
+// IgnoreNamespaceNameFunc returns name with name.Space cleared. The same local
+// name in different namespaces will be treated as identical names.
+func IgnoreNamespaceNameFunc(name xml.Name) xml.Name {
+	return xml.Name{
+		Local: name.Local,
 	}
-	return values
 }
 
-// sortedKeys returns the keys of m in order.
-func sortedKeys[M ~map[K]V, K cmp.Ordered, V any](m M) []K {
-	keys := mapKeys(m)
-	slices.Sort(keys)
-	return keys
+// The IdentityNameFunc returns name unchanged. The same local name in different
+// namespaces will be treated as distinct names.
+func IdentityNameFunc(name xml.Name) xml.Name {
+	return name
+}
+
+// TitleFirstRuneExportNameFunc returns name.Local with the initial rune
+// capitalized.
+func TitleFirstRuneExportNameFunc(name xml.Name) string {
+	runes := []rune(name.Local)
+	runes[0] = unicode.ToUpper(runes[0])
+	return string(runes)
 }