Repository: diegoholiveira/jsonlogic (go)
Issue: ApplyInterface does not support int number values
```
func main() {
	rule := map[string]interface{}{
		"==": []interface{}{
			map[string]interface{}{
				"var": "impact_levels",
			},
			1,
		},
	}

	data := map[string]interface{}{
		"impact_levels": 1,
	}

	output, err := jsonlogic.ApplyInterface(rule, data)
	if err != nil {
		fmt.Println(err)
		return
	}

	fmt.Println(output.(bool))
}
```
this returns an error, the reason seems to be that isNumber is checking for reflect.Float64, and therefor the int is assumed to be a string. 
Pull request description: feat: support parsing of int
Fixes #77 by allowing to parse `int` type

Patch:
diff --git a/helpers.go b/helpers.go
index cc859ec..d50fe0b 100644
--- a/helpers.go
+++ b/helpers.go
@@ -18,7 +18,12 @@ func isString(obj interface{}) bool {
 }
 
 func isNumber(obj interface{}) bool {
-	return is(obj, reflect.Float64)
+	switch obj.(type) {
+	case int, float64:
+		return true
+	default:
+		return false
+	}
 }
 
 func isPrimitive(obj interface{}) bool {
@@ -68,12 +73,22 @@ func toNumber(value interface{}) float64 {
 		return w
 	}
 
-	return value.(float64)
+	switch value.(type) {
+	case int:
+		return float64(value.(int))
+	default:
+		return value.(float64)
+	}
 }
 
 func toString(value interface{}) string {
 	if isNumber(value) {
-		return strconv.FormatFloat(value.(float64), 'f', -1, 64)
+		switch value.(type) {
+		case int:
+			return strconv.FormatInt(int64(value.(int)), 10)
+		default:
+			return strconv.FormatFloat(value.(float64), 'f', -1, 64)
+		}
 	}
 
 	if value == nil {


Test patch:
diff --git a/helpers_test.go b/helpers_test.go
index 2eb07ba..dc2018b 100644
--- a/helpers_test.go
+++ b/helpers_test.go
@@ -10,13 +10,124 @@ func TestHelperIsTrue(t *testing.T) {
 	assert.False(t, isTrue(nil))
 }
 
-func TestToString(t *testing.T) {
-	assert.Equal(t, "", toString(nil))
-}
-
 func TestToSliceOfNumbers(t *testing.T) {
 	json_parsed := []interface{}{"0.0", "-10.0"}
 	input := interface{}(json_parsed)
 	expected := []float64{0.0, -10.0}
 	assert.Equal(t, expected, toSliceOfNumbers(input))
 }
+
+func TestIsNumber(t *testing.T) {
+	tests := []struct {
+		name   string
+		input  interface{}
+		expect bool
+	}{
+		{
+			name:   "int max",
+			input:  9223372036854775807,
+			expect: true,
+		},
+		{
+			name:   "int min",
+			input:  -9223372036854775808,
+			expect: true,
+		},
+		{
+			name:   "float",
+			input:  1.121,
+			expect: true,
+		},
+		{
+			name:   "string",
+			input:  "123",
+			expect: false,
+		},
+		{
+			name:   "boolean",
+			input:  true,
+			expect: false,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			assert.Equal(t, test.expect, isNumber(test.input))
+		})
+	}
+}
+
+func TestToNumber(t *testing.T) {
+	tests := []struct {
+		name   string
+		input  interface{}
+		expect float64
+	}{
+		{
+			name:   "int max value",
+			input:  9223372036854775807,
+			expect: 9223372036854775807,
+		},
+		{
+			name:   "int min value",
+			input:  -9223372036854775808,
+			expect: -9223372036854775808,
+		},
+		{
+			name:   "int min value",
+			input:  -9223372036854775808,
+			expect: -9223372036854775808,
+		},
+		{
+			name:   "int as a string",
+			input:  "123",
+			expect: 123,
+		},
+		{
+			name:   "float",
+			input:  1.121,
+			expect: 1.121,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			assert.Equal(t, test.expect, toNumber(test.input))
+		})
+	}
+}
+
+func TestToString(t *testing.T) {
+	var tests = []struct {
+		name   string
+		input  interface{}
+		expect string
+	}{
+		{
+			name:   "nil value",
+			input:  nil,
+			expect: "",
+		},
+		{
+			name:   "string value",
+			input:  "value",
+			expect: "value",
+		},
+		{
+			name:   "int value",
+			input:  9223372036854775807,
+			expect: "9223372036854775807",
+		},
+		{
+			name:   "float value",
+			input:  1.21,
+			expect: "1.21",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			assert.Equal(t, test.expect, toString(test.input))
+		})
+	}
+}