Merge pull request #483 from ipld/schema-concatenation

Additional access to schema/dmt package; schema concatenation feature

Author: warpfork

node/bindnode/fuzz_test.go

@@ -149,7 +149,7 @@ func FuzzBindnodeViaDagCBOR(f *testing.F) {
 		if err != nil {
 			f.Fatal(err)
 		}
-		schemaNode := bindnode.Wrap(schemaDMT, schemadmt.Type.Schema.Type())
+		schemaNode := bindnode.Wrap(schemaDMT, schemadmt.Prototypes.Schema.Type())
 		schemaDagCBOR := marshalDagCBOR(f, schemaNode.Representation())
 
 		nodeBuilder := basicnode.Prototype.Any.NewBuilder()
@@ -178,7 +178,7 @@ func FuzzBindnodeViaDagCBOR(f *testing.F) {
 		}
 	}
 	f.Fuzz(func(t *testing.T, schemaDagCBOR, nodeDagCBOR []byte) {
-		schemaBuilder := schemadmt.Type.Schema.Representation().NewBuilder()
+		schemaBuilder := schemadmt.Prototypes.Schema.Representation().NewBuilder()
 
 		if err := dagcbor.Decode(schemaBuilder, bytes.NewReader(schemaDagCBOR)); err != nil {
 			t.Skipf("invalid schema-schema dag-cbor: %v", err)

schema/dmt/operations.go

@@ -0,0 +1,27 @@
+package schemadmt
+
+import (
+	"github.com/ipld/go-ipld-prime/datamodel"
+	"github.com/ipld/go-ipld-prime/node/bindnode"
+)
+
+// ConcatenateSchemas returns a new schema DMT object containing the
+// type declarations from both.
+//
+// As is usual for DMT form data, there is no check about the validity
+// of the result yet; you'll need to apply `Compile` on the produced value
+// to produce a usable compiled typesystem or to become certain that
+// all references in the DMT are satisfied, etc.
+func ConcatenateSchemas(a, b *Schema) *Schema {
+	// The joy of having an intermediate form that's just regular data model:
+	// we can implement this by simply using data model "copy" operations,
+	// and the result is correct.
+	nb := Prototypes.Schema.NewBuilder()
+	if err := datamodel.Copy(bindnode.Wrap(a, Prototypes.Schema.Type()), nb); err != nil {
+		panic(err)
+	}
+	if err := datamodel.Copy(bindnode.Wrap(b, Prototypes.Schema.Type()), nb); err != nil {
+		panic(err)
+	}
+	return bindnode.Unwrap(nb.Build()).(*Schema)
+}

schema/dmt/roundtrip_test.go

@@ -33,7 +33,7 @@ func testRoundtrip(t *testing.T, want string, updateFn func(string)) {
 
 	crre := regexp.MustCompile(`\r?\n`)
 	want = crre.ReplaceAllString(want, "\n")
-	nb := schemadmt.Type.Schema.Representation().NewBuilder()
+	nb := schemadmt.Prototypes.Schema.Representation().NewBuilder()
 	err := ipldjson.Decode(nb, strings.NewReader(want))
 	qt.Assert(t, err, qt.IsNil)
 	node := nb.Build().(schema.TypedNode)

schema/dmt/schema.go

@@ -10,13 +10,13 @@ import (
 
 // This schema follows https://ipld.io/specs/schemas/schema-schema.ipldsch.
 
-var Type struct {
+var Prototypes struct {
 	Schema schema.TypedPrototype
 }
 
 //go:generate go run -tags=schemadmtgen gen.go
 
-var schemaTypeSystem schema.TypeSystem
+var TypeSystem schema.TypeSystem
 
 func init() {
 	var ts schema.TypeSystem
@@ -433,10 +433,10 @@ func init() {
 		panic("not happening")
 	}
 
-	schemaTypeSystem = ts
+	TypeSystem = ts
 
-	Type.Schema = bindnode.Prototype(
+	Prototypes.Schema = bindnode.Prototype(
 		(*Schema)(nil),
-		schemaTypeSystem.TypeByName("Schema"),
+		TypeSystem.TypeByName("Schema"),
 	)
 }

schema/dsl/parse_test.go

@@ -116,7 +116,7 @@ func testParse(t *testing.T, inSchema, inJSON string, updateFn func(string)) {
 	// Ensure we can encode the schema as the json codec,
 	// and that it results in the same bytes as the ipldsch.json file.
 	{
-		node := bindnode.Wrap(sch, schemadmt.Type.Schema.Type())
+		node := bindnode.Wrap(sch, schemadmt.Prototypes.Schema.Type())
 
 		var buf bytes.Buffer
 		err := ipldjson.Encode(node.Representation(), &buf)