Add option to jp.Walk for leaves only (#150)

CHANGELOG.md

@@ -4,6 +4,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 The structure and content of this file follows [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
+## [1.20.3] - 2023-11-09
+### Added
+- Added an option to jp.Walk to just callback on leaves making the function more useable.
+
 ## [1.20.2] - 2023-10-30
 ### Fixed
 - A script of `@.x` is now read correctly as `@.x exists true`.

jp/walk.go

@@ -5,40 +5,69 @@ package jp
 import (
 	"time"
 
+	"github.com/ohler55/ojg/alt"
 	"github.com/ohler55/ojg/gen"
 )
 
 // Walk data and call the cb callback for each node in the data. The path is
 // reused in each call so if the path needs to be save it should be copied.
-func Walk(data any, cb func(path Expr, value any)) {
+func Walk(data any, cb func(path Expr, value any), justLeaves ...bool) {
 	path := Expr{Root('$')}
-	walk(path, data, cb)
+	walk(path, data, cb, 0 < len(justLeaves) && justLeaves[0])
 }
 
-func walk(path Expr, data any, cb func(path Expr, value any)) {
-	cb(path, data)
+func walk(path Expr, data any, cb func(path Expr, value any), justLeaves bool) {
+top:
 	switch td := data.(type) {
 	case nil, bool, int64, float64, string,
 		int, int8, int16, int32, uint, uint8, uint16, uint32, uint64, float32,
 		[]byte, time.Time:
 		// leaf node
+		cb(path, data)
 	case []any:
+		if !justLeaves {
+			cb(path, data)
+		}
+		pi := len(path)
+		path = append(path, nil)
 		for i, v := range td {
-			walk(append(path, Nth(i)), v, cb)
+			path[pi] = Nth(i)
+			walk(path, v, cb, justLeaves)
 		}
 	case map[string]any:
+		if !justLeaves {
+			cb(path, data)
+		}
+		pi := len(path)
+		path = append(path, nil)
 		for k, v := range td {
-			walk(append(path, Child(k)), v, cb)
+			path[pi] = Child(k)
+			walk(path, v, cb, justLeaves)
 		}
 	case gen.Array:
+		if !justLeaves {
+			cb(path, data)
+		}
+		pi := len(path)
+		path = append(path, nil)
 		for i, v := range td {
-			walk(append(path, Nth(i)), v, cb)
+			path[pi] = Nth(i)
+			walk(path, v, cb, justLeaves)
 		}
 	case gen.Object:
+		if !justLeaves {
+			cb(path, data)
+		}
+		pi := len(path)
+		path = append(path, nil)
 		for k, v := range td {
-			walk(append(path, Child(k)), v, cb)
+			path[pi] = Child(k)
+			walk(path, v, cb, justLeaves)
 		}
+	case alt.Simplifier:
+		data = td.Simplify()
+		goto top
 	default:
-		// TBD use reflection
+		cb(path, data)
 	}
 }

jp/walk_test.go

@@ -8,16 +8,31 @@ import (
 
 	"github.com/ohler55/ojg/gen"
 	"github.com/ohler55/ojg/jp"
+	"github.com/ohler55/ojg/pretty"
 	"github.com/ohler55/ojg/sen"
 	"github.com/ohler55/ojg/tt"
 )
 
+type simple int
+
+func (s simple) Simplify() any {
+	return map[string]any{"x": int64(s)}
+}
+
+type other int
+
 func TestWalk(t *testing.T) {
-	data := map[string]any{"a": []any{1, 2, 3}, "b": nil}
+	data := map[string]any{"a": []any{1, 2, 3}, "b": nil, "c": simple(4), "d": other(5)}
 	var paths []string
 	jp.Walk(data, func(path jp.Expr, value any) { paths = append(paths, path.String()) })
 	sort.Strings(paths)
-	tt.Equal(t, `[$ $.a "$.a[0]" "$.a[1]" "$.a[2]" $.b]`, string(sen.Bytes(paths)))
+	tt.Equal(t, `[$ $.a "$.a[0]" "$.a[1]" "$.a[2]" $.b $.c $.c.x $.d]`, string(sen.Bytes(paths)))
+
+	leaves := map[string]any{}
+	jp.Walk(data, func(path jp.Expr, value any) {
+		leaves[path[1:].String()] = value
+	}, true)
+	tt.Equal(t, `{"a[0]": 1 "a[1]": 2 "a[2]": 3 b: null c.x: 4 d: 5}`, pretty.SEN(leaves))
 }
 
 func TestWalkNode(t *testing.T) {

notes

@@ -1,6 +1,4 @@
 
-
-
 - script.go
  - API to add functions
   - RegisterUnaryFunction(name string, get bool, f func(arg any) any)