mirror of https://github.com/tidwall/gjson.git
Added Subselectors
It now possible to select multiple independent paths and join
their results into a single JSON document.
For example, given the following JSON
{
"info": {
"friends": [
{"first": "Dale", "last": "Murphy", "age": 44},
{"first": "Roger", "last": "Craig", "age": 68},
{"first": "Jane", "last": "Murphy", "age": 47}
]
}
}
The path `[info.friends.0.first,info.friends.1.last]` returns
["Dale","Craig"]
Or path `{info.friends.0.first,info.friends.1.last}` returns
{"first":"Dale","last":"Craig"}
You can also rename Object members such as
`{"alt1":info.friends.0.first,"alt2":info.friends.1.last}` returns
{"alt1":"Dale","alt2":"Craig"}
Finally you can combine this with any GJSON component
`info.friends.[0.first,1.age]` returns
["Dale",68]
This feature was request by @errashe in issue #113.
This commit is contained in:
tidwall
parent
001444ea45
commit
3b5bf6bb5e
188
gjson.go
188
gjson.go
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@ -865,10 +865,12 @@ func parseObjectPath(path string) (r objectPathResult) {
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return
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}
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if path[i] == '.' {
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// peek at the next byte and see if it's a '@' modifier.
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// peek at the next byte and see if it's a '@', '[', or '{'.
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r.part = path[:i]
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if !DisableModifiers &&
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i < len(path)-1 && path[i+1] == '@' {
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i < len(path)-1 &&
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(path[i+1] == '@' ||
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path[i+1] == '[' || path[i+1] == '{') {
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r.pipe = path[i+1:]
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r.piped = true
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} else {
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@ -1552,6 +1554,110 @@ func ForEachLine(json string, iterator func(line Result) bool) {
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}
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}
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type subSelector struct {
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name string
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path string
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}
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// parseSubSelectors returns the subselectors belonging to a '[path1,path2]' or
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// '{"field1":path1,"field2":path2}' type subSelection. It's expected that the
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// first character in path is either '[' or '{', and has already been checked
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// prior to calling this function.
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func parseSubSelectors(path string) (sels []subSelector, out string, ok bool) {
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depth := 1
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colon := 0
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start := 1
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i := 1
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pushSel := func() {
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var sel subSelector
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if colon == 0 {
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sel.path = path[start:i]
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} else {
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sel.name = path[start:colon]
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sel.path = path[colon+1 : i]
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}
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sels = append(sels, sel)
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colon = 0
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start = i + 1
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}
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for ; i < len(path); i++ {
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switch path[i] {
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case '\\':
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i++
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case ':':
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if depth == 1 {
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colon = i
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}
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case ',':
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if depth == 1 {
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pushSel()
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}
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case '"':
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i++
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loop:
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for ; i < len(path); i++ {
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switch path[i] {
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case '\\':
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i++
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case '"':
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break loop
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}
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}
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case '[', '(', '{':
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depth++
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case ']', ')', '}':
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depth--
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if depth == 0 {
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pushSel()
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path = path[i+1:]
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return sels, path, true
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}
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}
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}
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return
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}
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// nameOfLast returns the name of the last component
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func nameOfLast(path string) string {
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for i := len(path) - 1; i >= 0; i-- {
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if path[i] == '|' || path[i] == '.' {
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if i > 0 {
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if path[i-1] == '\\' {
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continue
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}
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}
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return path[i+1:]
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}
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}
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return path
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}
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func isSimpleName(component string) bool {
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for i := 0; i < len(component); i++ {
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if component[i] < ' ' {
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return false
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}
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switch component[i] {
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case '[', ']', '{', '}', '(', ')', '#', '|':
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return false
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}
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}
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return true
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}
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func appendJSONString(dst []byte, s string) []byte {
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for i := 0; i < len(s); i++ {
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if s[i] < ' ' || s[i] == '\\' || s[i] == '"' || s[i] > 126 {
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d, _ := json.Marshal(s)
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return append(dst, string(d)...)
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}
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}
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dst = append(dst, '"')
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dst = append(dst, s...)
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dst = append(dst, '"')
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return dst
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}
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type parseContext struct {
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json string
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value Result
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@ -1595,22 +1701,84 @@ type parseContext struct {
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// If you are consuming JSON from an unpredictable source then you may want to
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// use the Valid function first.
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func Get(json, path string) Result {
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if !DisableModifiers {
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if len(path) > 1 && path[0] == '@' {
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// possible modifier
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if len(path) > 1 {
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if !DisableModifiers {
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if path[0] == '@' {
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// possible modifier
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var ok bool
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var rjson string
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path, rjson, ok = execModifier(json, path)
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if ok {
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if len(path) > 0 && (path[0] == '|' || path[0] == '.') {
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res := Get(rjson, path[1:])
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res.Index = 0
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return res
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}
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return Parse(rjson)
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}
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}
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}
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if path[0] == '[' || path[0] == '{' {
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// using a subselector path
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kind := path[0]
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var ok bool
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var rjson string
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path, rjson, ok = execModifier(json, path)
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var subs []subSelector
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subs, path, ok = parseSubSelectors(path)
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if ok {
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if len(path) > 0 && (path[0] == '|' || path[0] == '.') {
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res := Get(rjson, path[1:])
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if len(path) == 0 || (path[0] == '|' || path[0] == '.') {
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var b []byte
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b = append(b, kind)
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var i int
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for _, sub := range subs {
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res := Get(json, sub.path)
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if res.Exists() {
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if i > 0 {
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b = append(b, ',')
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}
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if kind == '{' {
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if len(sub.name) > 0 {
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if sub.name[0] == '"' && Valid(sub.name) {
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b = append(b, sub.name...)
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} else {
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b = appendJSONString(b, sub.name)
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}
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} else {
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last := nameOfLast(sub.path)
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if isSimpleName(last) {
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b = appendJSONString(b, last)
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} else {
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b = appendJSONString(b, "_")
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}
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}
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b = append(b, ':')
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}
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var raw string
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if len(res.Raw) == 0 {
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raw = res.String()
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if len(raw) == 0 {
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raw = "null"
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}
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} else {
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raw = res.Raw
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}
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b = append(b, raw...)
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i++
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}
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}
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b = append(b, kind+2)
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var res Result
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res.Raw = string(b)
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res.Type = JSON
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if len(path) > 0 {
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res = res.Get(path[1:])
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}
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res.Index = 0
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return res
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}
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return Parse(rjson)
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}
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}
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}
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var i int
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var c = &parseContext{json: json}
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if len(path) >= 2 && path[0] == '.' && path[1] == '.' {
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@ -1862,3 +1862,52 @@ func TestParenQueries(t *testing.T) {
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assert(t, Get(json, "friends.#(a>10)#|#").Int() == 3)
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assert(t, Get(json, "friends.#(a>40)#|#").Int() == 0)
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}
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func TestSubSelectors(t *testing.T) {
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json := `{
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"info": {
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"friends": [
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{
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"first": "Dale", "last": "Murphy", "kind": "Person",
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"cust1": true,
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"extra": [10,20,30],
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"details": {
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"city": "Tempe",
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"state": "Arizona"
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}
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},
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{
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"first": "Roger", "last": "Craig", "kind": "Person",
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"cust2": false,
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"extra": [40,50,60],
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"details": {
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"city": "Phoenix",
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"state": "Arizona"
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}
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}
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]
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}
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}`
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assert(t, Get(json, "[]").String() == "[]")
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assert(t, Get(json, "{}").String() == "{}")
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res := Get(json, `{`+
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`abc:info.friends.0.first,`+
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`info.friends.1.last,`+
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`"a`+"\r"+`a":info.friends.0.kind,`+
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`"abc":info.friends.1.kind,`+
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`{123:info.friends.1.cust2},`+
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`[info.friends.#[details.city="Phoenix"]#|#]`+
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`}.@pretty.@ugly`).String()
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// println(res)
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// {"abc":"Dale","last":"Craig","\"a\ra\"":"Person","_":{"123":false},"_":[1]}
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assert(t, Get(res, "abc").String() == "Dale")
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assert(t, Get(res, "last").String() == "Craig")
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assert(t, Get(res, "\"a\ra\"").String() == "Person")
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assert(t, Get(res, "@reverse.abc").String() == "Person")
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assert(t, Get(res, "_.123").String() == "false")
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assert(t, Get(res, "@reverse._.0").String() == "1")
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assert(t, Get(json, "info.friends.[0.first,1.extra.0]").String() ==
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`["Dale",40]`)
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assert(t, Get(json, "info.friends.#.[first,extra.0]").String() ==
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`[["Dale",10],["Roger",40]]`)
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}
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