Add support for json.Number. (#414)
This commit adds support for encoding json.Number as a number
instead of as a string, which is the underlying type of
json.Number.
Care has been taken to not introduce a dependency on the
encoding/json package, by using an interface that specifies the
methods of json.Number instead of the datatype itself. This also
means that other packages that use a similar datatype will be
supported. (Like json-iterator)
This is useful for tools that wish to convert JSON data into YAML
data by deserializing JSON into a map[string]interface{}, and use
the json.Encoder's UseNumber() method, or structs that use the
json.Number datatype and also wish to support yaml.diff --git a/decode_test.go b/decode_test.go
index 9269f12..b05c466 100644
--- a/decode_test.go
+++ b/decode_test.go
@@ -714,6 +714,14 @@
"---\nhello\n...\n}not yaml",
"hello",
},
+ {
+ "a: 5\n",
+ &struct{ A jsonNumberT }{"5"},
+ },
+ {
+ "a: 5.5\n",
+ &struct{ A jsonNumberT }{"5.5"},
+ },
}
type M map[interface{}]interface{}
diff --git a/encode.go b/encode.go
index a14435e..0ee738e 100644
--- a/encode.go
+++ b/encode.go
@@ -13,6 +13,19 @@
"unicode/utf8"
)
+// jsonNumber is the interface of the encoding/json.Number datatype.
+// Repeating the interface here avoids a dependency on encoding/json, and also
+// supports other libraries like jsoniter, which use a similar datatype with
+// the same interface. Detecting this interface is useful when dealing with
+// structures containing json.Number, which is a string under the hood. The
+// encoder should prefer the use of Int64(), Float64() and string(), in that
+// order, when encoding this type.
+type jsonNumber interface {
+ Float64() (float64, error)
+ Int64() (int64, error)
+ String() string
+}
+
type encoder struct {
emitter yaml_emitter_t
event yaml_event_t
@@ -89,6 +102,21 @@
}
iface := in.Interface()
switch m := iface.(type) {
+ case jsonNumber:
+ integer, err := m.Int64()
+ if err == nil {
+ // In this case the json.Number is a valid int64
+ in = reflect.ValueOf(integer)
+ break
+ }
+ float, err := m.Float64()
+ if err == nil {
+ // In this case the json.Number is a valid float64
+ in = reflect.ValueOf(float)
+ break
+ }
+ // fallback case - no number could be obtained
+ in = reflect.ValueOf(m.String())
case time.Time, *time.Time:
// Although time.Time implements TextMarshaler,
// we don't want to treat it as a string for YAML
diff --git a/encode_test.go b/encode_test.go
index f0911a7..4a26600 100644
--- a/encode_test.go
+++ b/encode_test.go
@@ -15,6 +15,24 @@
"gopkg.in/yaml.v2"
)
+type jsonNumberT string
+
+func (j jsonNumberT) Int64() (int64, error) {
+ val, err := strconv.Atoi(string(j))
+ if err != nil {
+ return 0, err
+ }
+ return int64(val), nil
+}
+
+func (j jsonNumberT) Float64() (float64, error) {
+ return strconv.ParseFloat(string(j), 64)
+}
+
+func (j jsonNumberT) String() string {
+ return string(j)
+}
+
var marshalIntTest = 123
var marshalTests = []struct {
@@ -367,6 +385,18 @@
map[string]string{"a": "你好 #comment"},
"a: '你好 #comment'\n",
},
+ {
+ map[string]interface{}{"a": jsonNumberT("5")},
+ "a: 5\n",
+ },
+ {
+ map[string]interface{}{"a": jsonNumberT("100.5")},
+ "a: 100.5\n",
+ },
+ {
+ map[string]interface{}{"a": jsonNumberT("bogus")},
+ "a: bogus\n",
+ },
}
func (s *S) TestMarshal(c *C) {
