Add in_sorted_list operator (#21)

- Adds in_sorted_list operator to make it faster when searching in huge lists. (Using binary search algorithm)

jsonlogic.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"math"
 	"reflect"
+	"sort"
 	"strings"
 
 	"github.com/mitchellh/copystructure"
@@ -114,6 +115,40 @@ func _inRange(value interface{}, values interface{}) bool {
 	return toString(value) >= toString(i) && toString(j) >= toString(value)
 }
 
+// Expect values to be in alphabetical ascending order
+func _inSorted(value interface{}, values interface{}) bool {
+	valuesSlice := values.([]interface{})
+
+	findElement := func(i int) bool {
+		element := valuesSlice[i]
+
+		if isSlice(valuesSlice[i]) {
+			sliceElement := valuesSlice[i].([]interface{})
+			start := sliceElement[0]
+			end := sliceElement[1]
+
+			return (toString(start) <= toString(value) && toString(end) >= toString(value)) || toString(end) > toString(value)
+		}
+
+		return toString(element) >= toString(value)
+	}
+
+	i := sort.Search(len(valuesSlice),  findElement)
+	if i >= len(valuesSlice) {
+		return false
+	}
+
+	if isSlice(valuesSlice[i]) {
+		sliceElement := valuesSlice[i].([]interface{})
+		start := sliceElement[0]
+		end := sliceElement[1]
+
+		return toString(start) <= toString(value) && toString(end) >= toString(value)
+	}
+
+	return toString(valuesSlice[i]) == toString(value)
+}
+
 func _in(value interface{}, values interface{}) bool {
 	if isString(values) {
 		return strings.Contains(values.(string), value.(string))
@@ -580,6 +615,10 @@ func operation(operator string, values, data interface{}) interface{} {
 		return _in(parsed[0], parsed[1])
 	}
 
+	if operator == "in_sorted" {
+		return _inSorted(parsed[0], parsed[1])
+	}
+
 	if operator == "%" {
 		return mod(parsed[0], parsed[1])
 	}

jsonlogic_test.go

@@ -184,6 +184,59 @@ func TestListOfRanges(t *testing.T) {
 	assert.JSONEq(t, expected, result.String())
 }
 
+func TestInSortedOperator(t *testing.T) {
+	rule := strings.NewReader(`{
+		"filter": [
+			{"var": "people"},
+			{"in_sorted": [
+				{"var": ".age"},
+				[
+					11.00,
+					[12, 14],
+					[13, 18],
+					2,
+					"20",
+					[32, 38],
+					"a",
+					["b", "d"]					
+				]
+			]}
+		]
+	}`)
+
+	data := strings.NewReader(`{
+		"people": [
+			{"age":"18", "name":"John"},
+			{"age":20, "name":"Luke"},
+			{"age":18, "name":"Mark"},
+			{"age":40, "name":"Donald"},
+			{"age":11, "name":"Mickey"},
+			{"age":"1", "name":"Minnie"},
+			{"age":2, "name":"Mario"},
+			{"age":"a", "name":"Mario"},
+			{"age":"c", "name":"Princess"}
+		]
+	}`)
+
+	var result bytes.Buffer
+	err := Apply(rule, data, &result)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expected := `[
+		{"age":"18", "name": "John"},
+		{"age":20, "name":"Luke"},
+		{"age":18, "name": "Mark"},
+		{"age":11, "name":"Mickey"},
+		{"age":2, "name":"Mario"},
+		{"age":"a", "name":"Mario"},
+		{"age":"c", "name":"Princess"}
+	]`
+
+	assert.JSONEq(t, expected, result.String())
+}
+
 func TestSomeWithLists(t *testing.T) {
 	rule := strings.NewReader(`{
 		"some": [