Refactor string representation of tokens

Author: aeijdenberg

patch/pointer.go

@@ -114,47 +114,17 @@ func (p Pointer) IsSet() bool { return len(p.tokens) > 0 }
 func (p Pointer) String() string {
 	var strs []string
 
-	optional := false
-
+	seenOptional := false
 	for _, token := range p.tokens {
-		switch typedToken := token.(type) {
-		case RootToken:
-			strs = append(strs, "")
-
-		case IndexToken:
-			strs = append(strs, fmt.Sprintf("%d", typedToken.Index))
-
-		case AfterLastIndexToken:
-			strs = append(strs, "-")
-
-		case MatchingIndexToken:
-			key := rfc6901Encoder.Replace(typedToken.Key)
-			val := rfc6901Encoder.Replace(typedToken.Value)
-
-			if typedToken.Optional {
-				if !optional {
-					val += "?"
-					optional = true
-				}
+		s := token.String()
+		if strings.HasSuffix(s, "?") {
+			if seenOptional {
+				s = s[:len(s)-1]
+			} else {
+				seenOptional = true
 			}
-
-			strs = append(strs, fmt.Sprintf("%s=%s", key, val))
-
-		case KeyToken:
-			str := rfc6901Encoder.Replace(typedToken.Key)
-
-			if typedToken.Optional { // /key?/key2/key3
-				if !optional {
-					str += "?"
-					optional = true
-				}
-			}
-
-			strs = append(strs, str)
-
-		default:
-			panic(fmt.Sprintf("Unknown token type '%T'", typedToken))
 		}
+		strs = append(strs, s)
 	}
 
 	return strings.Join(strs, "/")

patch/token_afterlastindex.go

@@ -7,6 +7,10 @@ import (
 
 type AfterLastIndexToken struct{}
 
+func (t AfterLastIndexToken) String() string {
+	return "-"
+}
+
 func (t AfterLastIndexToken) processDescent(ctx *tokenContext) (interface{}, error) {
 	switch ctx.Method {
 	case methodFind:

patch/token_index.go

@@ -1,11 +1,18 @@
 package patch
 
-import "errors"
+import (
+	"errors"
+	"fmt"
+)
 
 type IndexToken struct {
 	Index int
 }
 
+func (t IndexToken) String() string {
+	return fmt.Sprintf("%d", t.Index)
+}
+
 func (t IndexToken) processDescent(ctx *tokenContext) (interface{}, error) {
 	typedObj, ok := ctx.Node.([]interface{})
 	if !ok {

patch/token_key.go

@@ -11,6 +11,16 @@ type KeyToken struct {
 	Optional bool
 }
 
+func (t KeyToken) String() string {
+	str := rfc6901Encoder.Replace(t.Key)
+
+	if t.Optional { // /key?/key2/key3
+		str += "?"
+	}
+
+	return str
+}
+
 func (t KeyToken) processDescent(ctx *tokenContext) (interface{}, error) {
 	typedObj, ok := ctx.Node.(map[interface{}]interface{})
 	if !ok {

patch/token_matchingindex.go

@@ -1,6 +1,9 @@
 package patch
 
-import "errors"
+import (
+	"errors"
+	"fmt"
+)
 
 type MatchingIndexToken struct {
 	Key   string
@@ -9,6 +12,17 @@ type MatchingIndexToken struct {
 	Optional bool
 }
 
+func (t MatchingIndexToken) String() string {
+	key := rfc6901Encoder.Replace(t.Key)
+	val := rfc6901Encoder.Replace(t.Value)
+
+	if t.Optional {
+		val += "?"
+	}
+
+	return fmt.Sprintf("%s=%s", key, val)
+}
+
 func (t MatchingIndexToken) processDescent(ctx *tokenContext) (interface{}, error) {
 	typedObj, ok := ctx.Node.([]interface{})
 	if !ok {

patch/token_root.go

@@ -4,6 +4,10 @@ import "errors"
 
 type RootToken struct{}
 
+func (t RootToken) String() string {
+	return ""
+}
+
 func (t RootToken) processDescent(ctx *tokenContext) (interface{}, error) {
 	return nil, errors.New("not supported")
 }

patch/token_wildcard.go

@@ -4,6 +4,10 @@ import "errors"
 
 type WildcardToken struct{}
 
+func (t WildcardToken) String() string {
+	return "*"
+}
+
 func (t WildcardToken) processDescent(ctx *tokenContext) (interface{}, error) {
 	if ctx.IsLast() {
 		return nil, errors.New("wildcard can't be used for last element. Use - instead")

patch/tokens.go

@@ -33,4 +33,5 @@ func (rc *tokenContext) Descend() (interface{}, error) {
 type Token interface {
 	processDescent(ctx *tokenContext) (interface{}, error)
 	createEmptyValueForNext() (interface{}, error)
+	String() string
 }