(feat)Add extension operator "range"

Author: huangjunwen

ext/ext.go

@@ -0,0 +1,94 @@
+package ext
+
+import (
+	"fmt"
+
+	"github.com/huangjunwen/jsonlogic-go"
+)
+
+// AddOpRange adds "range" operation to the JSONLogic instance. The op accept 1 to 3 numeric params and
+// generate a range of numbers, examples:
+//   - {"range":null} -> []
+//   - {"range":0} -> []
+//   - {"range":2} -> [0,1]
+//   - {"range":-2} -> [0,-1]
+//   - {"range":[3,6]} -> [3,4,5]
+//   - {"range":[6,3]} -> [6,5,4]
+//   - {"range":[3,6,2]} -> [3,5]
+//   - {"range":[6,3,-2]} -> [6,4]
+func AddOpRange(jl *jsonlogic.JSONLogic) {
+	jl.AddOperation("range", opRange)
+}
+
+func opRange(apply jsonlogic.Applier, params []interface{}, data interface{}) (result interface{}, err error) {
+	if len(params) < 1 {
+		return nil, fmt.Errorf("range: expect at least one param")
+	}
+
+	params, err = jsonlogic.ApplyParams(apply, params, data)
+	if err != nil {
+		return
+	}
+	var b, e, s interface{}
+	switch len(params) {
+	default:
+		fallthrough
+	case 3:
+		b = params[0]
+		e = params[1]
+		s = params[2]
+	case 2:
+		b = params[0]
+		e = params[1]
+	case 1:
+		b = float64(0)
+		e = params[0]
+	}
+
+	bf64, err := jsonlogic.ToNumeric(b)
+	if err != nil {
+		return nil, fmt.Errorf("range: get begin error %s", err.Error())
+	}
+	ef64, err := jsonlogic.ToNumeric(e)
+	if err != nil {
+		return nil, fmt.Errorf("range: get end error %s", err.Error())
+	}
+	sf64, err := jsonlogic.ToNumeric(s)
+	if err != nil {
+		return nil, fmt.Errorf("range: get step error %s", err.Error())
+	}
+
+	var (
+		begin = int(bf64)
+		end   = int(ef64)
+		step  = int(sf64)
+	)
+	if end == begin {
+		return []interface{}{}, nil
+	}
+	if end > begin {
+		if step == 0 {
+			step = 1
+		}
+		if step < 0 {
+			return nil, fmt.Errorf("range: end > begin but got negative step")
+		}
+		ret := []interface{}{}
+		for i := begin; i < end; i += step {
+			ret = append(ret, float64(i))
+		}
+		return ret, nil
+	}
+
+	if step == 0 {
+		step = -1
+	}
+	if step > 0 {
+		return nil, fmt.Errorf("range: end < begin but got postive step")
+	}
+	ret := []interface{}{}
+	for i := begin; i > end; i += step {
+		ret = append(ret, float64(i))
+	}
+	return ret, nil
+}

ext/ext_test.go

@@ -0,0 +1,27 @@
+package ext
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/huangjunwen/jsonlogic-go"
+)
+
+func TestOpRange(t *testing.T) {
+	assert := assert.New(t)
+	jl := jsonlogic.NewEmpty()
+	AddOpRange(jl)
+	jsonlogic.TestCases{
+		{Logic: `{"range":null}`, Data: `null`, Result: []interface{}{}},
+		{Logic: `{"range":0}`, Data: `null`, Result: []interface{}{}},
+		{Logic: `{"range":2}`, Data: `null`, Result: []interface{}{float64(0), float64(1)}},
+		{Logic: `{"range":-2}`, Data: `null`, Result: []interface{}{float64(0), float64(-1)}},
+		{Logic: `{"range":[3,6]}`, Data: `null`, Result: []interface{}{float64(3), float64(4), float64(5)}},
+		{Logic: `{"range":[6,3]}`, Data: `null`, Result: []interface{}{float64(6), float64(5), float64(4)}},
+		{Logic: `{"range":[3,6,2]}`, Data: `null`, Result: []interface{}{float64(3), float64(5)}},
+		{Logic: `{"range":[6,3,-2]}`, Data: `null`, Result: []interface{}{float64(6), float64(4)}},
+		{Logic: `{"range":[3,6,-1]}`, Data: `null`, Err: true},
+		{Logic: `{"range":[6,3,2]}`, Data: `null`, Err: true},
+	}.Run(assert, jl)
+}