added numeric indexing in get

lib/doc.go

@@ -4,6 +4,8 @@ import (
 	"encoding/json"
 	"fmt"
 	"reflect"
+	"strconv"
+	"strings"
 )
 
 type Doc struct {
@@ -19,9 +21,12 @@ func (d *Doc) Get(path string, dest interface{}) error {
 		return fmt.Errorf("no item found at path %s (doc is empty)", path)
 	}
 
-	v, ok := d.items[path]
-	if !ok {
-		return fmt.Errorf("no item found at path %s", path)
+	var v interface{}
+	parts := strings.Split(path, "/")
+
+	v, err := seekValue(path, parts, d.items)
+	if err != nil {
+		return err
 	}
 
 	dt := reflect.TypeOf(dest)
@@ -34,3 +39,41 @@ func (d *Doc) Get(path string, dest interface{}) error {
 	dve.Set(reflect.ValueOf(v))
 	return nil
 }
+
+func seekValue(fullpath string, parts []string, root interface{}) (interface{}, error) {
+	if len(parts) == 0 {
+		return nil, fmt.Errorf("path is empty")
+	}
+
+	head, tail := parts[0], parts[1:]
+	n, err := strconv.Atoi(head)
+	if err == nil {
+		l, ok := root.([]interface{})
+		if !ok {
+			return nil, fmt.Errorf("can only index a []interface{}, root is %s", reflect.TypeOf(root))
+		}
+		if n >= len(l) {
+			return nil, fmt.Errorf("path %s is out of bounds, can't get the %d index from a slice of len %d", fullpath, n, len(l))
+		}
+		v := l[n]
+		if len(tail) == 0 {
+			return v, nil
+		}
+		return seekValue(fullpath, tail, v)
+	}
+
+	m, ok := root.(map[string]interface{})
+	if !ok {
+		return nil, fmt.Errorf("can only key a map[string]interface{}, root is %v", reflect.TypeOf(root))
+	}
+
+	v, ok := m[head]
+	if !ok {
+		return nil, fmt.Errorf("unable to seek value at path %s: no value found for part %s", fullpath, head)
+	}
+
+	if len(tail) == 0 {
+		return v, nil
+	}
+	return seekValue(fullpath, tail, v)
+}