server/server.go - external/github.com/google/cel-go - Git at Google

 // Copyright 2018 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //      http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 // Package server defines the gRPC conformance test server for CEL Go.
 package server

 import (
 	"context"
 	"fmt"

 	"github.com/golang/protobuf/proto"
 	"github.com/golang/protobuf/ptypes"
 	"github.com/google/cel-go/cel"
 	"github.com/google/cel-go/common"
 	"github.com/google/cel-go/common/types"
 	"github.com/google/cel-go/common/types/ref"
 	"github.com/google/cel-go/common/types/traits"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"

 	test2pb "github.com/google/cel-spec/proto/test/v1/proto2/test_all_types"
 	test3pb "github.com/google/cel-spec/proto/test/v1/proto3/test_all_types"
 	exprpb "google.golang.org/genproto/googleapis/api/expr/v1alpha1"
 	rpc "google.golang.org/genproto/googleapis/rpc/status"
 )

 // ConformanceServer contains the server state.
 type ConformanceServer struct{}

 // Parse implements ConformanceService.Parse.
 func (s *ConformanceServer) Parse(ctx context.Context, in *exprpb.ParseRequest) (*exprpb.ParseResponse, error) {
 	if in.CelSource == "" {
 		st := status.New(codes.InvalidArgument, "No source code.")
 		return nil, st.Err()
 	}
 	// NOTE: syntax_version isn't currently used
 	var parseOptions []cel.EnvOption
 	if in.DisableMacros {
 		parseOptions = append(parseOptions, cel.ClearMacros())
 	}
 	env, _ := cel.NewEnv(parseOptions...)
 	past, iss := env.Parse(in.CelSource)
 	resp := exprpb.ParseResponse{}
 	if iss == nil || iss.Err() == nil {
 		// Success
 		resp.ParsedExpr, _ = cel.AstToParsedExpr(past)
 	} else {
 		// Failure
 		appendErrors(iss.Errors(), &resp.Issues)
 	}
 	return &resp, nil
 }

 // Check implements ConformanceService.Check.
 func (s *ConformanceServer) Check(ctx context.Context, in *exprpb.CheckRequest) (*exprpb.CheckResponse, error) {
 	if in.ParsedExpr == nil {
 		st := status.New(codes.InvalidArgument, "No parsed expression.")
 		return nil, st.Err()
 	}
 	if in.ParsedExpr.SourceInfo == nil {
 		st := status.New(codes.InvalidArgument, "No source info.")
 		return nil, st.Err()
 	}
 	// Build the environment.
 	var checkOptions []cel.EnvOption = []cel.EnvOption{cel.StdLib()}
 	if in.NoStdEnv {
 		checkOptions = []cel.EnvOption{}
 	}
 	checkOptions = append(checkOptions, cel.Container(in.Container))
 	checkOptions = append(checkOptions, cel.Declarations(in.TypeEnv...))
 	checkOptions = append(checkOptions, cel.Types(&test2pb.TestAllTypes{}))
 	checkOptions = append(checkOptions, cel.Types(&test3pb.TestAllTypes{}))
 	env, _ := cel.NewCustomEnv(checkOptions...)

 	// Check the expression.
 	cast, iss := env.Check(cel.ParsedExprToAst(in.ParsedExpr))
 	resp := exprpb.CheckResponse{}
 	if iss == nil || iss.Err() == nil {
 		// Success
 		resp.CheckedExpr, _ = cel.AstToCheckedExpr(cast)
 	} else {
 		// Failure
 		appendErrors(iss.Errors(), &resp.Issues)
 	}
 	return &resp, nil
 }

 // Eval implements ConformanceService.Eval.
 func (s *ConformanceServer) Eval(ctx context.Context, in *exprpb.EvalRequest) (*exprpb.EvalResponse, error) {
 	env, _ := cel.NewEnv(cel.Container(in.Container),
 		cel.Types(&test2pb.TestAllTypes{}, &test3pb.TestAllTypes{}))
 	var prg cel.Program
 	var err error
 	switch in.ExprKind.(type) {
 	case *exprpb.EvalRequest_ParsedExpr:
 		ast := cel.ParsedExprToAst(in.GetParsedExpr())
 		prg, err = env.Program(ast)
 		if err != nil {
 			return nil, err
 		}
 	case *exprpb.EvalRequest_CheckedExpr:
 		ast := cel.CheckedExprToAst(in.GetCheckedExpr())
 		prg, err = env.Program(ast)
 		if err != nil {
 			return nil, err
 		}
 	default:
 		st := status.New(codes.InvalidArgument, "No expression.")
 		return nil, st.Err()
 	}
 	args := make(map[string]interface{})
 	for name, exprValue := range in.Bindings {
 		refVal, err := ExprValueToRefValue(env.TypeAdapter(), exprValue)
 		if err != nil {
 			return nil, fmt.Errorf("can't convert binding %s: %s", name, err)
 		}
 		args[name] = refVal
 	}
 	// NOTE: the EvalState is currently discarded
 	res, _, err := prg.Eval(args)
 	resultExprVal, err := RefValueToExprValue(res, err)
 	if err != nil {
 		return nil, fmt.Errorf("con't convert result: %s", err)
 	}
 	return &exprpb.EvalResponse{Result: resultExprVal}, nil
 }

 // appendErrors converts the errors from errs to Status messages
 // and appends them to the list of issues.
 func appendErrors(errs []common.Error, issues *[]*rpc.Status) {
 	for _, e := range errs {
 		status := ErrToStatus(e, exprpb.IssueDetails_ERROR)
 		*issues = append(*issues, status)
 	}
 }

 // ErrToStatus converts an Error to a Status message with the given severity.
 func ErrToStatus(e common.Error, severity exprpb.IssueDetails_Severity) *rpc.Status {
 	detail := exprpb.IssueDetails{
 		Severity: severity,
 		Position: &exprpb.SourcePosition{
 			Line:   int32(e.Location.Line()),
 			Column: int32(e.Location.Column()),
 		},
 	}
 	s := status.New(codes.InvalidArgument, e.Message)
 	sd, err := s.WithDetails(&detail)
 	if err == nil {
 		return sd.Proto()
 	}
 	return s.Proto()
 }

 // TODO(jimlarson): The following conversion code should be moved to
 // common/types/provider.go and consolidated/refactored as appropriate.
 // In particular, make judicious use of types.NativeToValue().

 // RefValueToExprValue converts between ref.Val and exprpb.ExprValue.
 func RefValueToExprValue(res ref.Val, err error) (*exprpb.ExprValue, error) {
 	if err != nil {
 		s := status.Convert(err).Proto()
 		return &exprpb.ExprValue{
 			Kind: &exprpb.ExprValue_Error{
 				Error: &exprpb.ErrorSet{
 					Errors: []*rpc.Status{s},
 				},
 			},
 		}, nil
 	}
 	if types.IsUnknown(res) {
 		return &exprpb.ExprValue{
 			Kind: &exprpb.ExprValue_Unknown{
 				Unknown: &exprpb.UnknownSet{
 					Exprs: res.Value().([]int64),
 				},
 			}}, nil
 	}
 	v, err := RefValueToValue(res)
 	if err != nil {
 		return nil, err
 	}
 	return &exprpb.ExprValue{
 		Kind: &exprpb.ExprValue_Value{Value: v}}, nil
 }

 var (
 	typeNameToTypeValue = map[string]*types.TypeValue{
 		"bool":      types.BoolType,
 		"bytes":     types.BytesType,
 		"double":    types.DoubleType,
 		"null_type": types.NullType,
 		"int":       types.IntType,
 		"list":      types.ListType,
 		"map":       types.MapType,
 		"string":    types.StringType,
 		"type":      types.TypeType,
 		"uint":      types.UintType,
 	}
 )

 // RefValueToValue converts between ref.Val and Value.
 // The ref.Val must not be error or unknown.
 func RefValueToValue(res ref.Val) (*exprpb.Value, error) {
 	switch res.Type() {
 	case types.BoolType:
 		return &exprpb.Value{
 			Kind: &exprpb.Value_BoolValue{BoolValue: res.Value().(bool)}}, nil
 	case types.BytesType:
 		return &exprpb.Value{
 			Kind: &exprpb.Value_BytesValue{BytesValue: res.Value().([]byte)}}, nil
 	case types.DoubleType:
 		return &exprpb.Value{
 			Kind: &exprpb.Value_DoubleValue{DoubleValue: res.Value().(float64)}}, nil
 	case types.IntType:
 		return &exprpb.Value{
 			Kind: &exprpb.Value_Int64Value{Int64Value: res.Value().(int64)}}, nil
 	case types.ListType:
 		l := res.(traits.Lister)
 		sz := l.Size().(types.Int)
 		elts := make([]*exprpb.Value, 0, int64(sz))
 		for i := types.Int(0); i < sz; i++ {
 			v, err := RefValueToValue(l.Get(i))
 			if err != nil {
 				return nil, err
 			}
 			elts = append(elts, v)
 		}
 		return &exprpb.Value{
 			Kind: &exprpb.Value_ListValue{
 				ListValue: &exprpb.ListValue{Values: elts}}}, nil
 	case types.MapType:
 		mapper := res.(traits.Mapper)
 		sz := mapper.Size().(types.Int)
 		entries := make([]*exprpb.MapValue_Entry, 0, int64(sz))
 		for it := mapper.Iterator(); it.HasNext().(types.Bool); {
 			k := it.Next()
 			v := mapper.Get(k)
 			kv, err := RefValueToValue(k)
 			if err != nil {
 				return nil, err
 			}
 			vv, err := RefValueToValue(v)
 			if err != nil {
 				return nil, err
 			}
 			entries = append(entries, &exprpb.MapValue_Entry{Key: kv, Value: vv})
 		}
 		return &exprpb.Value{
 			Kind: &exprpb.Value_MapValue{
 				MapValue: &exprpb.MapValue{Entries: entries}}}, nil
 	case types.NullType:
 		return &exprpb.Value{
 			Kind: &exprpb.Value_NullValue{}}, nil
 	case types.StringType:
 		return &exprpb.Value{
 			Kind: &exprpb.Value_StringValue{StringValue: res.Value().(string)}}, nil
 	case types.TypeType:
 		typeName := res.(ref.Type).TypeName()
 		return &exprpb.Value{Kind: &exprpb.Value_TypeValue{TypeValue: typeName}}, nil
 	case types.UintType:
 		return &exprpb.Value{
 			Kind: &exprpb.Value_Uint64Value{Uint64Value: res.Value().(uint64)}}, nil
 	default:
 		// Object type
 		pb, ok := res.Value().(proto.Message)
 		if !ok {
 			return nil, status.New(codes.InvalidArgument, "Expected proto message").Err()
 		}
 		any, err := ptypes.MarshalAny(pb)
 		if err != nil {
 			return nil, err
 		}
 		return &exprpb.Value{
 			Kind: &exprpb.Value_ObjectValue{ObjectValue: any}}, nil
 	}
 }

 // ExprValueToRefValue converts between exprpb.ExprValue and ref.Val.
 func ExprValueToRefValue(adapter ref.TypeAdapter, ev *exprpb.ExprValue) (ref.Val, error) {
 	switch ev.Kind.(type) {
 	case *exprpb.ExprValue_Value:
 		return ValueToRefValue(adapter, ev.GetValue())
 	case *exprpb.ExprValue_Error:
 		// An error ExprValue is a repeated set of rpc.Status
 		// messages, with no convention for the status details.
 		// To convert this to a types.Err, we need to convert
 		// these Status messages to a single string, and be
 		// able to decompose that string on output so we can
 		// round-trip arbitrary ExprValue messages.
 		// TODO(jimlarson) make a convention for this.
 		return types.NewErr("XXX add details later"), nil
 	case *exprpb.ExprValue_Unknown:
 		return types.Unknown(ev.GetUnknown().Exprs), nil
 	}
 	return nil, status.New(codes.InvalidArgument, "unknown ExprValue kind").Err()
 }

 // ValueToRefValue converts between exprpb.Value and ref.Val.
 func ValueToRefValue(adapter ref.TypeAdapter, v *exprpb.Value) (ref.Val, error) {
 	switch v.Kind.(type) {
 	case *exprpb.Value_NullValue:
 		return types.NullValue, nil
 	case *exprpb.Value_BoolValue:
 		return types.Bool(v.GetBoolValue()), nil
 	case *exprpb.Value_Int64Value:
 		return types.Int(v.GetInt64Value()), nil
 	case *exprpb.Value_Uint64Value:
 		return types.Uint(v.GetUint64Value()), nil
 	case *exprpb.Value_DoubleValue:
 		return types.Double(v.GetDoubleValue()), nil
 	case *exprpb.Value_StringValue:
 		return types.String(v.GetStringValue()), nil
 	case *exprpb.Value_BytesValue:
 		return types.Bytes(v.GetBytesValue()), nil
 	case *exprpb.Value_ObjectValue:
 		any := v.GetObjectValue()
 		var msg ptypes.DynamicAny
 		if err := ptypes.UnmarshalAny(any, &msg); err != nil {
 			return nil, err
 		}
 		return adapter.NativeToValue(msg.Message), nil
 	case *exprpb.Value_MapValue:
 		m := v.GetMapValue()
 		entries := make(map[ref.Val]ref.Val)
 		for _, entry := range m.Entries {
 			key, err := ValueToRefValue(adapter, entry.Key)
 			if err != nil {
 				return nil, err
 			}
 			pb, err := ValueToRefValue(adapter, entry.Value)
 			if err != nil {
 				return nil, err
 			}
 			entries[key] = pb
 		}
 		return adapter.NativeToValue(entries), nil
 	case *exprpb.Value_ListValue:
 		l := v.GetListValue()
 		elts := make([]ref.Val, len(l.Values))
 		for i, e := range l.Values {
 			rv, err := ValueToRefValue(adapter, e)
 			if err != nil {
 				return nil, err
 			}
 			elts[i] = rv
 		}
 		return adapter.NativeToValue(elts), nil
 	case *exprpb.Value_TypeValue:
 		typeName := v.GetTypeValue()
 		tv, ok := typeNameToTypeValue[typeName]
 		if ok {
 			return tv, nil
 		}
 		return types.NewObjectTypeValue(typeName), nil
 	}
 	return nil, status.New(codes.InvalidArgument, "unknown value").Err()
 }
	// Copyright 2018 Google LLC
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	// Package server defines the gRPC conformance test server for CEL Go.
	package server

	import (
	"context"
	"fmt"

	"github.com/golang/protobuf/proto"
	"github.com/golang/protobuf/ptypes"
	"github.com/google/cel-go/cel"
	"github.com/google/cel-go/common"
	"github.com/google/cel-go/common/types"
	"github.com/google/cel-go/common/types/ref"
	"github.com/google/cel-go/common/types/traits"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"

	test2pb "github.com/google/cel-spec/proto/test/v1/proto2/test_all_types"
	test3pb "github.com/google/cel-spec/proto/test/v1/proto3/test_all_types"
	exprpb "google.golang.org/genproto/googleapis/api/expr/v1alpha1"
	rpc "google.golang.org/genproto/googleapis/rpc/status"
	)

	// ConformanceServer contains the server state.
	type ConformanceServer struct{}

	// Parse implements ConformanceService.Parse.
	func (s ConformanceServer) Parse(ctx context.Context, in exprpb.ParseRequest) (*exprpb.ParseResponse, error) {
	if in.CelSource == "" {
	st := status.New(codes.InvalidArgument, "No source code.")
	return nil, st.Err()
	}
	// NOTE: syntax_version isn't currently used
	var parseOptions []cel.EnvOption
	if in.DisableMacros {
	parseOptions = append(parseOptions, cel.ClearMacros())
	}
	env, _ := cel.NewEnv(parseOptions...)
	past, iss := env.Parse(in.CelSource)
	resp := exprpb.ParseResponse{}
	if iss == nil \|\| iss.Err() == nil {
	// Success
	resp.ParsedExpr, _ = cel.AstToParsedExpr(past)
	} else {
	// Failure
	appendErrors(iss.Errors(), &resp.Issues)
	}
	return &resp, nil
	}

	// Check implements ConformanceService.Check.
	func (s ConformanceServer) Check(ctx context.Context, in exprpb.CheckRequest) (*exprpb.CheckResponse, error) {
	if in.ParsedExpr == nil {
	st := status.New(codes.InvalidArgument, "No parsed expression.")
	return nil, st.Err()
	}
	if in.ParsedExpr.SourceInfo == nil {
	st := status.New(codes.InvalidArgument, "No source info.")
	return nil, st.Err()
	}
	// Build the environment.
	var checkOptions []cel.EnvOption = []cel.EnvOption{cel.StdLib()}
	if in.NoStdEnv {
	checkOptions = []cel.EnvOption{}
	}
	checkOptions = append(checkOptions, cel.Container(in.Container))
	checkOptions = append(checkOptions, cel.Declarations(in.TypeEnv...))
	checkOptions = append(checkOptions, cel.Types(&test2pb.TestAllTypes{}))
	checkOptions = append(checkOptions, cel.Types(&test3pb.TestAllTypes{}))
	env, _ := cel.NewCustomEnv(checkOptions...)

	// Check the expression.
	cast, iss := env.Check(cel.ParsedExprToAst(in.ParsedExpr))
	resp := exprpb.CheckResponse{}
	if iss == nil \|\| iss.Err() == nil {
	// Success
	resp.CheckedExpr, _ = cel.AstToCheckedExpr(cast)
	} else {
	// Failure
	appendErrors(iss.Errors(), &resp.Issues)
	}
	return &resp, nil
	}

	// Eval implements ConformanceService.Eval.
	func (s ConformanceServer) Eval(ctx context.Context, in exprpb.EvalRequest) (*exprpb.EvalResponse, error) {
	env, _ := cel.NewEnv(cel.Container(in.Container),
	cel.Types(&test2pb.TestAllTypes{}, &test3pb.TestAllTypes{}))
	var prg cel.Program
	var err error
	switch in.ExprKind.(type) {
	case *exprpb.EvalRequest_ParsedExpr:
	ast := cel.ParsedExprToAst(in.GetParsedExpr())
	prg, err = env.Program(ast)
	if err != nil {
	return nil, err
	}
	case *exprpb.EvalRequest_CheckedExpr:
	ast := cel.CheckedExprToAst(in.GetCheckedExpr())
	prg, err = env.Program(ast)
	if err != nil {
	return nil, err
	}
	default:
	st := status.New(codes.InvalidArgument, "No expression.")
	return nil, st.Err()
	}
	args := make(map[string]interface{})
	for name, exprValue := range in.Bindings {
	refVal, err := ExprValueToRefValue(env.TypeAdapter(), exprValue)
	if err != nil {
	return nil, fmt.Errorf("can't convert binding %s: %s", name, err)
	}
	args[name] = refVal
	}
	// NOTE: the EvalState is currently discarded
	res, _, err := prg.Eval(args)
	resultExprVal, err := RefValueToExprValue(res, err)
	if err != nil {
	return nil, fmt.Errorf("con't convert result: %s", err)
	}
	return &exprpb.EvalResponse{Result: resultExprVal}, nil
	}

	// appendErrors converts the errors from errs to Status messages
	// and appends them to the list of issues.
	func appendErrors(errs []common.Error, issues []rpc.Status) {
	for _, e := range errs {
	status := ErrToStatus(e, exprpb.IssueDetails_ERROR)
	issues = append(issues, status)
	}
	}

	// ErrToStatus converts an Error to a Status message with the given severity.
	func ErrToStatus(e common.Error, severity exprpb.IssueDetails_Severity) *rpc.Status {
	detail := exprpb.IssueDetails{
	Severity: severity,
	Position: &exprpb.SourcePosition{
	Line: int32(e.Location.Line()),
	Column: int32(e.Location.Column()),
	},
	}
	s := status.New(codes.InvalidArgument, e.Message)
	sd, err := s.WithDetails(&detail)
	if err == nil {
	return sd.Proto()
	}
	return s.Proto()
	}

	// TODO(jimlarson): The following conversion code should be moved to
	// common/types/provider.go and consolidated/refactored as appropriate.
	// In particular, make judicious use of types.NativeToValue().

	// RefValueToExprValue converts between ref.Val and exprpb.ExprValue.
	func RefValueToExprValue(res ref.Val, err error) (*exprpb.ExprValue, error) {
	if err != nil {
	s := status.Convert(err).Proto()
	return &exprpb.ExprValue{
	Kind: &exprpb.ExprValue_Error{
	Error: &exprpb.ErrorSet{
	Errors: []*rpc.Status{s},
	},
	},
	}, nil
	}
	if types.IsUnknown(res) {
	return &exprpb.ExprValue{
	Kind: &exprpb.ExprValue_Unknown{
	Unknown: &exprpb.UnknownSet{
	Exprs: res.Value().([]int64),
	},
	}}, nil
	}
	v, err := RefValueToValue(res)
	if err != nil {
	return nil, err
	}
	return &exprpb.ExprValue{
	Kind: &exprpb.ExprValue_Value{Value: v}}, nil
	}

	var (
	typeNameToTypeValue = map[string]*types.TypeValue{
	"bool": types.BoolType,
	"bytes": types.BytesType,
	"double": types.DoubleType,
	"null_type": types.NullType,
	"int": types.IntType,
	"list": types.ListType,
	"map": types.MapType,
	"string": types.StringType,
	"type": types.TypeType,
	"uint": types.UintType,
	}
	)

	// RefValueToValue converts between ref.Val and Value.
	// The ref.Val must not be error or unknown.
	func RefValueToValue(res ref.Val) (*exprpb.Value, error) {
	switch res.Type() {
	case types.BoolType:
	return &exprpb.Value{
	Kind: &exprpb.Value_BoolValue{BoolValue: res.Value().(bool)}}, nil
	case types.BytesType:
	return &exprpb.Value{
	Kind: &exprpb.Value_BytesValue{BytesValue: res.Value().([]byte)}}, nil
	case types.DoubleType:
	return &exprpb.Value{
	Kind: &exprpb.Value_DoubleValue{DoubleValue: res.Value().(float64)}}, nil
	case types.IntType:
	return &exprpb.Value{
	Kind: &exprpb.Value_Int64Value{Int64Value: res.Value().(int64)}}, nil
	case types.ListType:
	l := res.(traits.Lister)
	sz := l.Size().(types.Int)
	elts := make([]*exprpb.Value, 0, int64(sz))
	for i := types.Int(0); i < sz; i++ {
	v, err := RefValueToValue(l.Get(i))
	if err != nil {
	return nil, err
	}
	elts = append(elts, v)
	}
	return &exprpb.Value{
	Kind: &exprpb.Value_ListValue{
	ListValue: &exprpb.ListValue{Values: elts}}}, nil
	case types.MapType:
	mapper := res.(traits.Mapper)
	sz := mapper.Size().(types.Int)
	entries := make([]*exprpb.MapValue_Entry, 0, int64(sz))
	for it := mapper.Iterator(); it.HasNext().(types.Bool); {
	k := it.Next()
	v := mapper.Get(k)
	kv, err := RefValueToValue(k)
	if err != nil {
	return nil, err
	}
	vv, err := RefValueToValue(v)
	if err != nil {
	return nil, err
	}
	entries = append(entries, &exprpb.MapValue_Entry{Key: kv, Value: vv})
	}
	return &exprpb.Value{
	Kind: &exprpb.Value_MapValue{
	MapValue: &exprpb.MapValue{Entries: entries}}}, nil
	case types.NullType:
	return &exprpb.Value{
	Kind: &exprpb.Value_NullValue{}}, nil
	case types.StringType:
	return &exprpb.Value{
	Kind: &exprpb.Value_StringValue{StringValue: res.Value().(string)}}, nil
	case types.TypeType:
	typeName := res.(ref.Type).TypeName()
	return &exprpb.Value{Kind: &exprpb.Value_TypeValue{TypeValue: typeName}}, nil
	case types.UintType:
	return &exprpb.Value{
	Kind: &exprpb.Value_Uint64Value{Uint64Value: res.Value().(uint64)}}, nil
	default:
	// Object type
	pb, ok := res.Value().(proto.Message)
	if !ok {
	return nil, status.New(codes.InvalidArgument, "Expected proto message").Err()
	}
	any, err := ptypes.MarshalAny(pb)
	if err != nil {
	return nil, err
	}
	return &exprpb.Value{
	Kind: &exprpb.Value_ObjectValue{ObjectValue: any}}, nil
	}
	}

	// ExprValueToRefValue converts between exprpb.ExprValue and ref.Val.
	func ExprValueToRefValue(adapter ref.TypeAdapter, ev *exprpb.ExprValue) (ref.Val, error) {
	switch ev.Kind.(type) {
	case *exprpb.ExprValue_Value:
	return ValueToRefValue(adapter, ev.GetValue())
	case *exprpb.ExprValue_Error:
	// An error ExprValue is a repeated set of rpc.Status
	// messages, with no convention for the status details.
	// To convert this to a types.Err, we need to convert
	// these Status messages to a single string, and be
	// able to decompose that string on output so we can
	// round-trip arbitrary ExprValue messages.
	// TODO(jimlarson) make a convention for this.
	return types.NewErr("XXX add details later"), nil
	case *exprpb.ExprValue_Unknown:
	return types.Unknown(ev.GetUnknown().Exprs), nil
	}
	return nil, status.New(codes.InvalidArgument, "unknown ExprValue kind").Err()
	}

	// ValueToRefValue converts between exprpb.Value and ref.Val.
	func ValueToRefValue(adapter ref.TypeAdapter, v *exprpb.Value) (ref.Val, error) {
	switch v.Kind.(type) {
	case *exprpb.Value_NullValue:
	return types.NullValue, nil
	case *exprpb.Value_BoolValue:
	return types.Bool(v.GetBoolValue()), nil
	case *exprpb.Value_Int64Value:
	return types.Int(v.GetInt64Value()), nil
	case *exprpb.Value_Uint64Value:
	return types.Uint(v.GetUint64Value()), nil
	case *exprpb.Value_DoubleValue:
	return types.Double(v.GetDoubleValue()), nil
	case *exprpb.Value_StringValue:
	return types.String(v.GetStringValue()), nil
	case *exprpb.Value_BytesValue:
	return types.Bytes(v.GetBytesValue()), nil
	case *exprpb.Value_ObjectValue:
	any := v.GetObjectValue()
	var msg ptypes.DynamicAny
	if err := ptypes.UnmarshalAny(any, &msg); err != nil {
	return nil, err
	}
	return adapter.NativeToValue(msg.Message), nil
	case *exprpb.Value_MapValue:
	m := v.GetMapValue()
	entries := make(map[ref.Val]ref.Val)
	for _, entry := range m.Entries {
	key, err := ValueToRefValue(adapter, entry.Key)
	if err != nil {
	return nil, err
	}
	pb, err := ValueToRefValue(adapter, entry.Value)
	if err != nil {
	return nil, err
	}
	entries[key] = pb
	}
	return adapter.NativeToValue(entries), nil
	case *exprpb.Value_ListValue:
	l := v.GetListValue()
	elts := make([]ref.Val, len(l.Values))
	for i, e := range l.Values {
	rv, err := ValueToRefValue(adapter, e)
	if err != nil {
	return nil, err
	}
	elts[i] = rv
	}
	return adapter.NativeToValue(elts), nil
	case *exprpb.Value_TypeValue:
	typeName := v.GetTypeValue()
	tv, ok := typeNameToTypeValue[typeName]
	if ok {
	return tv, nil
	}
	return types.NewObjectTypeValue(typeName), nil
	}
	return nil, status.New(codes.InvalidArgument, "unknown value").Err()
	}