Fixed binding with struct

cmdlang/builtins.go

@@ -113,6 +113,38 @@ func callBuiltin(ctx context.Context, args invocationArgs) (object, error) {
 	return inv.invoke(ctx, args.shift(1))
 }
 
+func indexBuiltin(ctx context.Context, args invocationArgs) (object, error) {
+	if err := args.expectArgn(1); err != nil {
+		return nil, err
+	}
+
+	val := args.args[0]
+	for _, idx := range args.args[1:] {
+		switch v := val.(type) {
+		case listable:
+			intIdx, ok := idx.(intObject)
+			if !ok {
+				return nil, errors.New("expected int for listable")
+			}
+			if int(intIdx) >= 0 && int(intIdx) < v.Len() {
+				val = v.Index(int(intIdx))
+			} else {
+				val = nil
+			}
+		case hashable:
+			strIdx, ok := idx.(strObject)
+			if !ok {
+				return nil, errors.New("expected string for hashable")
+			}
+			val = v.Value(string(strIdx))
+		default:
+			return val, nil
+		}
+	}
+
+	return val, nil
+}
+
 func mapBuiltin(ctx context.Context, args invocationArgs) (object, error) {
 	if err := args.expectArgn(2); err != nil {
 		return nil, err

cmdlang/inst.go

@@ -31,6 +31,7 @@ func New(opts ...InstOption) *Inst {
 	rootEC.addCmd("set", invokableFunc(setBuiltin))
 	rootEC.addCmd("toUpper", invokableFunc(toUpperBuiltin))
 	//rootEC.addCmd("cat", invokableFunc(catBuiltin))
+	rootEC.addCmd("index", invokableFunc(indexBuiltin))
 	rootEC.addCmd("call", invokableFunc(callBuiltin))
 
 	rootEC.addCmd("map", invokableFunc(mapBuiltin))

cmdlang/objs.go

@@ -20,6 +20,7 @@ type listable interface {
 
 type hashable interface {
 	Len() int
+	Value(k string) object
 	Each(func(k string, v object) error) error
 }
 
@@ -59,6 +60,10 @@ func (s hashObject) Len() int {
 	return len(s)
 }
 
+func (s hashObject) Value(k string) object {
+	return s[k]
+}
+
 func (s hashObject) Each(fn func(k string, v object) error) error {
 	for k, v := range s {
 		if err := fn(k, v); err != nil {
@@ -133,6 +138,8 @@ func toGoValue(obj object) (interface{}, bool) {
 		return v.p, true
 	case listableProxyObject:
 		return v.v.Interface(), true
+	case structProxyObject:
+		return v.v.Interface(), true
 	}
 
 	return nil, false
@@ -144,11 +151,16 @@ func fromGoValue(v any) (object, error) {
 		return nil, nil
 	case string:
 		return strObject(t), nil
+	case int:
+		return intObject(t), nil
 	}
 
 	resVal := reflect.ValueOf(v)
-	if resVal.Type().Kind() == reflect.Slice {
+	switch resVal.Kind() {
+	case reflect.Slice:
 		return listableProxyObject{resVal}, nil
+	case reflect.Struct:
+		return structProxyObject{resVal}, nil
 	}
 
 	return proxyObject{v}, nil
@@ -378,3 +390,42 @@ func (p listableProxyObject) Index(i int) object {
 	}
 	return e
 }
+
+type structProxyObject struct {
+	v reflect.Value
+}
+
+func (s structProxyObject) String() string {
+	return fmt.Sprintf("structProxyObject{%v}", s.v.Type())
+}
+
+func (s structProxyObject) Truthy() bool {
+	return true
+}
+
+func (s structProxyObject) Len() int {
+	return s.v.Type().NumField()
+}
+
+func (s structProxyObject) Value(k string) object {
+	e, err := fromGoValue(s.v.FieldByName(k).Interface())
+	if err != nil {
+		return nil
+	}
+	return e
+}
+
+func (s structProxyObject) Each(fn func(k string, v object) error) error {
+	for i := 0; i < s.v.Type().NumField(); i++ {
+		f := s.v.Type().Field(i).Name
+		v, err := fromGoValue(s.v.Field(i).Interface())
+		if err != nil {
+			v = nil
+		}
+
+		if err := fn(f, v); err != nil {
+			return err
+		}
+	}
+	return nil
+}

cmdlang/testbuiltins_test.go

@@ -188,6 +188,7 @@ func TestBuiltins_ForEach(t *testing.T) {
 		// TODO: hash is not sorted, so need to find a way to sort it
 		{desc: "iterate over map", expr: `
 			foreach [a:"1"] { |k v| echo $k "=" $v }`, want: "a=1\n(nil)\n"},
+		{desc: "iterate via pipe", expr: `["2" "4" "6"] | foreach { |x| echo $x }`, want: "2\n4\n6\n(nil)\n"},
 	}
 
 	for _, tt := range tests {
@@ -329,3 +330,59 @@ func TestBuiltins_Map(t *testing.T) {
 		})
 	}
 }
+
+func TestBuiltins_Index(t *testing.T) {
+	tests := []struct {
+		desc string
+		expr string
+		want string
+	}{
+		{desc: "index from list 1", expr: `index ["alpha" "beta" "gamma"] 0`, want: "alpha\n"},
+		{desc: "index from list 2", expr: `index ["alpha" "beta" "gamma"] 1`, want: "beta\n"},
+		{desc: "index from list 3", expr: `index ["alpha" "beta" "gamma"] 2`, want: "gamma\n"},
+		{desc: "index from list 4", expr: `index ["alpha" "beta" "gamma"] 3`, want: "(nil)\n"},
+
+		{desc: "index from hash 1", expr: `index ["first":"alpha" "second":"beta" "third":"gamma"] "first"`, want: "alpha\n"},
+		{desc: "index from hash 2", expr: `index ["first":"alpha" "second":"beta" "third":"gamma"] "second"`, want: "beta\n"},
+		{desc: "index from hash 3", expr: `index ["first":"alpha" "second":"beta" "third":"gamma"] "third"`, want: "gamma\n"},
+		{desc: "index from hash 4", expr: `index ["first":"alpha" "second":"beta" "third":"gamma"] "missing"`, want: "(nil)\n"},
+
+		{desc: "multi-list 1", expr: `index [[1 2] [3 4]] 0 1`, want: "2\n"},
+		{desc: "multi-list 2", expr: `index [[1 2] [3 4]] 1 0`, want: "3\n"},
+		{desc: "list of hash 1", expr: `index [["id":"abc"] ["id":"123"]] 0 id`, want: "abc\n"},
+		{desc: "list of hash 2", expr: `index [["id":"abc"] ["id":"123"]] 1 id`, want: "123\n"},
+
+		{desc: "go list 1", expr: `goInt | index 1`, want: "5\n"},
+		{desc: "go list 2", expr: `goInt | index 2`, want: "4\n"},
+		{desc: "go struct 1", expr: `goStruct | index Alpha`, want: "foo\n"},
+		{desc: "go struct 2", expr: `goStruct | index Beta`, want: "bar\n"},
+		{desc: "go struct 3", expr: `goStruct | index Gamma 1`, want: "33\n"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			ctx := context.Background()
+			outW := bytes.NewBuffer(nil)
+
+			inst := New(WithOut(outW), WithTestBuiltin())
+			inst.SetBuiltin("goInt", func(ctx context.Context, args CallArgs) (any, error) {
+				return []int{6, 5, 4}, nil
+			})
+			inst.SetBuiltin("goStruct", func(ctx context.Context, args CallArgs) (any, error) {
+				return struct {
+					Alpha string
+					Beta  string
+					Gamma []int
+				}{
+					Alpha: "foo",
+					Beta:  "bar",
+					Gamma: []int{22, 33},
+				}, nil
+			})
+			err := inst.EvalAndDisplay(ctx, tt.expr)
+
+			assert.NoError(t, err)
+			assert.Equal(t, tt.want, outW.String())
+		})
+	}
+}

cmdlang/userbuiltin.go

@@ -68,18 +68,33 @@ func bindArg(v interface{}, arg object) error {
 		*t = arg.String()
 	}
 
-	// Check for proxy object
-	if po, ok := arg.(proxyObject); ok {
-		poValue := reflect.ValueOf(po.p)
+	switch t := arg.(type) {
+	case proxyObject:
+		return bindProxyObject(v, reflect.ValueOf(t.p))
+	case listableProxyObject:
+		return bindProxyObject(v, t.v)
+	case structProxyObject:
+		return bindProxyObject(v, t.v)
+	}
+
+	return nil
+}
+
+func bindProxyObject(v interface{}, r reflect.Value) error {
 	argValue := reflect.ValueOf(v)
+	if argValue.Kind() != reflect.Ptr {
+		return errors.New("v must be a pointer to a struct")
+	}
 
-		if argValue.Type().Kind() != reflect.Pointer {
+	for {
+		if r.Type().AssignableTo(argValue.Elem().Type()) {
+			argValue.Elem().Set(r)
 			return nil
-		} else if !poValue.Type().AssignableTo(argValue.Elem().Type()) {
+		}
+		if r.Type().Kind() != reflect.Pointer {
 			return nil
 		}
 
-		argValue.Elem().Set(poValue)
+		r = r.Elem()
 	}
-	return nil
 }

cmdlang/userbuiltin_test.go

@@ -143,7 +143,6 @@ func TestInst_SetBuiltin(t *testing.T) {
 		}{
 			{descr: "return as is", expr: `countTo3`, want: []string{"1", "2", "3"}},
 			{descr: "iterate over", expr: `foreach (countTo3) { |x| echo $x }`, wantOut: "1\n2\n3\n"},
-			{descr: "iterate via foreach", expr: `["2" "4" "6"] | foreach { |x| echo $x }`, wantOut: "2\n4\n6\n"},
 		}
 
 		for _, tt := range tests {