meta,args: add missing Include, add iterator to use normal or Readonly the same way

pkg/args/args.go

@@ -5,6 +5,7 @@ package args
 
 import (
 	"fmt"
+	"iter"
 	"sort"
 	"strings"
 
@@ -54,21 +55,36 @@ func (a *Args) Add(key string, val any) error {
 	return nil
 }
 
+type Iterator interface {
+	Iter() iter.Seq2[string, ipld.Node]
+}
+
 // Include merges the provided arguments into the existing arguments.
 //
 // If duplicate keys are encountered, the new value is silently dropped
 // without causing an error.
-func (a *Args) Include(other *Args) {
-	for _, key := range other.Keys {
+func (a *Args) Include(other Iterator) {
+	for key, value := range other.Iter() {
 		if _, ok := a.Values[key]; ok {
 			// don't overwrite
 			continue
 		}
-		a.Values[key] = other.Values[key]
+		a.Values[key] = value
 		a.Keys = append(a.Keys, key)
 	}
 }
 
+// Iter iterates over the args key/values
+func (a *Args) Iter() iter.Seq2[string, ipld.Node] {
+	return func(yield func(string, ipld.Node) bool) {
+		for _, key := range a.Keys {
+			if !yield(key, a.Values[key]) {
+				return
+			}
+		}
+	}
+}
+
 // ToIPLD wraps an instance of an Args with an ipld.Node.
 func (a *Args) ToIPLD() (ipld.Node, error) {
 	sort.Strings(a.Keys)

pkg/args/args_test.go

@@ -1,6 +1,7 @@
 package args_test
 
 import (
+	"maps"
 	"sync"
 	"testing"
 
@@ -8,6 +9,7 @@ import (
 	"github.com/ipld/go-ipld-prime"
 	"github.com/ipld/go-ipld-prime/codec/dagcbor"
 	"github.com/ipld/go-ipld-prime/datamodel"
+	"github.com/ipld/go-ipld-prime/node/basicnode"
 	"github.com/ipld/go-ipld-prime/schema"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -133,6 +135,56 @@ func TestArgs_Include(t *testing.T) {
 	assert.Equal(t, "val4", must(argsIn.Values["key4"].AsString()))
 }
 
+func TestIterCloneEquals(t *testing.T) {
+	a := args.New()
+
+	require.NoError(t, a.Add("foo", "bar"))
+	require.NoError(t, a.Add("baz", 1234))
+
+	expected := map[string]ipld.Node{
+		"foo": basicnode.NewString("bar"),
+		"baz": basicnode.NewInt(1234),
+	}
+
+	// args -> iter
+	require.Equal(t, expected, maps.Collect(a.Iter()))
+
+	// readonly -> iter
+	ro := a.ReadOnly()
+	require.Equal(t, expected, maps.Collect(ro.Iter()))
+
+	// args -> clone -> iter
+	clone := a.Clone()
+	require.Equal(t, expected, maps.Collect(clone.Iter()))
+
+	// readonly -> WriteableClone -> iter
+	wclone := ro.WriteableClone()
+	require.Equal(t, expected, maps.Collect(wclone.Iter()))
+
+	require.True(t, a.Equals(wclone))
+	require.True(t, ro.Equals(wclone.ReadOnly()))
+}
+
+func TestInclude(t *testing.T) {
+	a1 := args.New()
+
+	require.NoError(t, a1.Add("samekey", "bar"))
+	require.NoError(t, a1.Add("baz", 1234))
+
+	a2 := args.New()
+
+	require.NoError(t, a2.Add("samekey", "othervalue")) // check no overwrite
+	require.NoError(t, a2.Add("otherkey", 1234))
+
+	a1.Include(a2)
+
+	require.Equal(t, map[string]ipld.Node{
+		"samekey":  basicnode.NewString("bar"),
+		"baz":      basicnode.NewInt(1234),
+		"otherkey": basicnode.NewInt(1234),
+	}, maps.Collect(a1.Iter()))
+}
+
 const (
 	argsSchema = "type Args { String : Any }"
 	argsName   = "Args"

pkg/args/readonly.go

@@ -1,17 +1,25 @@
 package args
 
-import "github.com/ipld/go-ipld-prime"
+import (
+	"iter"
+
+	"github.com/ipld/go-ipld-prime"
+)
 
 type ReadOnly struct {
 	args *Args
 }
 
+func (r ReadOnly) Iter() iter.Seq2[string, ipld.Node] {
+	return r.args.Iter()
+}
+
 func (r ReadOnly) ToIPLD() (ipld.Node, error) {
 	return r.args.ToIPLD()
 }
 
-func (r ReadOnly) Equals(other *Args) bool {
-	return r.args.Equals(other)
+func (r ReadOnly) Equals(other ReadOnly) bool {
+	return r.args.Equals(other.args)
 }
 
 func (r ReadOnly) String() string {