types: add Stringer implementation for Dict

Signed-off-by: Sebastien Binet <[email protected]>

types/dict.go

@@ -7,6 +7,7 @@ package types
 import (
 	"fmt"
 	"reflect"
+	"strings"
 )
 
 // DictSetter is implemented by any value that exhibits a dict-like behaviour,
@@ -88,3 +89,19 @@ func (*Dict) Call(args ...interface{}) (interface{}, error) {
 	}
 	return nil, fmt.Errorf("Dict: invalid arguments: %#v", args)
 }
+
+func (d *Dict) String() string {
+	if d == nil {
+		return "nil"
+	}
+	o := new(strings.Builder)
+	o.WriteString("{")
+	for i, e := range *d {
+		if i > 0 {
+			o.WriteString(", ")
+		}
+		fmt.Fprintf(o, "%v: %v", e.Key, e.Value)
+	}
+	o.WriteString("}")
+	return o.String()
+}

types/dict_test.go

@@ -1,6 +1,14 @@
+// Copyright 2023 NLP Odyssey Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
 package types
 
-import "testing"
+import (
+	"bytes"
+	"fmt"
+	"testing"
+)
 
 func TestDictCall(t *testing.T) {
 	d := NewDict()
@@ -14,3 +22,27 @@ func TestDictCall(t *testing.T) {
 		t.Errorf("expected %v, actual: %v", expected, actual)
 	}
 }
+
+func TestDictStringer(t *testing.T) {
+	dct := NewDict()
+	dct.Set("empty", NewDict())
+	dct.Set("one", "un")
+	dct.Set("two", "deux")
+	sub := NewDict()
+	sub.Set("eins", "one")
+	sub.Set("zwei", []string{"two", "deux"})
+	sub.Set(2, []int{2 * 2, 2 * 3, 2 * 4})
+	dct.Set("sub", sub)
+
+	buf := new(bytes.Buffer)
+	fmt.Fprintf(buf, "%v", dct)
+
+	var (
+		got  = buf.String()
+		want = "{empty: {}, one: un, two: deux, sub: {eins: one, zwei: [two deux], 2: [4 6 8]}}"
+	)
+
+	if got != want {
+		t.Fatalf("got= %q\nwant=%q", got, want)
+	}
+}