Extend template's basic math functions to accept float, uint and string values

This commit is contained in:
Tatsushi Demachi 2014-09-20 01:33:02 +09:00 committed by spf13
parent d5308e6f6f
commit 5d565c34e5
2 changed files with 211 additions and 4 deletions

View file

@ -233,6 +233,125 @@ func SafeHtml(text string) template.HTML {
return template.HTML(text) return template.HTML(text)
} }
func doArithmetic(a, b interface{}, op rune) (interface{}, error) {
av := reflect.ValueOf(a)
bv := reflect.ValueOf(b)
var ai, bi int64
var af, bf float64
var au, bu uint64
switch av.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
ai = av.Int()
switch bv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
bi = bv.Int()
case reflect.Float32, reflect.Float64:
af = float64(ai) // may overflow
ai = 0
bf = bv.Float()
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
bu = bv.Uint()
if ai >= 0 {
au = uint64(ai)
ai = 0
} else {
bi = int64(bu) // may overflow
bu = 0
}
default:
return nil, errors.New("Can't apply the operator to the values")
}
case reflect.Float32, reflect.Float64:
af = av.Float()
switch bv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
bf = float64(bv.Int()) // may overflow
case reflect.Float32, reflect.Float64:
bf = bv.Float()
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
bf = float64(bv.Uint()) // may overflow
default:
return nil, errors.New("Can't apply the operator to the values")
}
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
au = av.Uint()
switch bv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
bi = bv.Int()
if bi >= 0 {
bu = uint64(bi)
bi = 0
} else {
ai = int64(au) // may overflow
au = 0
}
case reflect.Float32, reflect.Float64:
af = float64(au) // may overflow
au = 0
bf = bv.Float()
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
bu = bv.Uint()
default:
return nil, errors.New("Can't apply the operator to the values")
}
case reflect.String:
as := av.String()
if bv.Kind() == reflect.String && op == '+' {
bs := bv.String()
return as + bs, nil
} else {
return nil, errors.New("Can't apply the operator to the values")
}
default:
return nil, errors.New("Can't apply the operator to the values")
}
switch op {
case '+':
if ai != 0 || bi != 0 {
return ai + bi, nil
} else if af != 0 || bf != 0 {
return af + bf, nil
} else if au != 0 || bu != 0 {
return au + bu, nil
} else {
return 0, nil
}
case '-':
if ai != 0 || bi != 0 {
return ai - bi, nil
} else if af != 0 || bf != 0 {
return af - bf, nil
} else if au != 0 || bu != 0 {
return au - bu, nil
} else {
return 0, nil
}
case '*':
if ai != 0 || bi != 0 {
return ai * bi, nil
} else if af != 0 || bf != 0 {
return af * bf, nil
} else if au != 0 || bu != 0 {
return au * bu, nil
} else {
return 0, nil
}
case '/':
if bi != 0 {
return ai / bi, nil
} else if bf != 0 {
return af / bf, nil
} else if bu != 0 {
return au / bu, nil
} else {
return nil, errors.New("Can't divide the value by 0")
}
default:
return nil, errors.New("There is no such an operation")
}
}
type Template interface { type Template interface {
ExecuteTemplate(wr io.Writer, name string, data interface{}) error ExecuteTemplate(wr io.Writer, name string, data interface{}) error
Lookup(name string) *template.Template Lookup(name string) *template.Template
@ -278,11 +397,11 @@ func NewTemplate() Template {
"first": First, "first": First,
"where": Where, "where": Where,
"highlight": Highlight, "highlight": Highlight,
"add": func(a, b int) int { return a + b }, "add": func(a, b interface{}) (interface{}, error) { return doArithmetic(a, b, '+') },
"sub": func(a, b int) int { return a - b }, "sub": func(a, b interface{}) (interface{}, error) { return doArithmetic(a, b, '-') },
"div": func(a, b int) int { return a / b }, "div": func(a, b interface{}) (interface{}, error) { return doArithmetic(a, b, '/') },
"mod": func(a, b int) int { return a % b }, "mod": func(a, b int) int { return a % b },
"mul": func(a, b int) int { return a * b }, "mul": func(a, b interface{}) (interface{}, error) { return doArithmetic(a, b, '*') },
"modBool": func(a, b int) bool { return a%b == 0 }, "modBool": func(a, b int) bool { return a%b == 0 },
"lower": func(a string) string { return strings.ToLower(a) }, "lower": func(a string) string { return strings.ToLower(a) },
"upper": func(a string) string { return strings.ToUpper(a) }, "upper": func(a string) string { return strings.ToUpper(a) },

View file

@ -35,6 +35,94 @@ func TestGt(t *testing.T) {
} }
} }
func TestDoArithmetic(t *testing.T) {
for i, this := range []struct {
a interface{}
b interface{}
op rune
expect interface{}
}{
{3, 2, '+', int64(5)},
{3, 2, '-', int64(1)},
{3, 2, '*', int64(6)},
{3, 2, '/', int64(1)},
{3.0, 2, '+', float64(5)},
{3.0, 2, '-', float64(1)},
{3.0, 2, '*', float64(6)},
{3.0, 2, '/', float64(1.5)},
{3, 2.0, '+', float64(5)},
{3, 2.0, '-', float64(1)},
{3, 2.0, '*', float64(6)},
{3, 2.0, '/', float64(1.5)},
{3.0, 2.0, '+', float64(5)},
{3.0, 2.0, '-', float64(1)},
{3.0, 2.0, '*', float64(6)},
{3.0, 2.0, '/', float64(1.5)},
{uint(3), uint(2), '+', uint64(5)},
{uint(3), uint(2), '-', uint64(1)},
{uint(3), uint(2), '*', uint64(6)},
{uint(3), uint(2), '/', uint64(1)},
{uint(3), 2, '+', uint64(5)},
{uint(3), 2, '-', uint64(1)},
{uint(3), 2, '*', uint64(6)},
{uint(3), 2, '/', uint64(1)},
{3, uint(2), '+', uint64(5)},
{3, uint(2), '-', uint64(1)},
{3, uint(2), '*', uint64(6)},
{3, uint(2), '/', uint64(1)},
{uint(3), -2, '+', int64(1)},
{uint(3), -2, '-', int64(5)},
{uint(3), -2, '*', int64(-6)},
{uint(3), -2, '/', int64(-1)},
{-3, uint(2), '+', int64(-1)},
{-3, uint(2), '-', int64(-5)},
{-3, uint(2), '*', int64(-6)},
{-3, uint(2), '/', int64(-1)},
{uint(3), 2.0, '+', float64(5)},
{uint(3), 2.0, '-', float64(1)},
{uint(3), 2.0, '*', float64(6)},
{uint(3), 2.0, '/', float64(1.5)},
{3.0, uint(2), '+', float64(5)},
{3.0, uint(2), '-', float64(1)},
{3.0, uint(2), '*', float64(6)},
{3.0, uint(2), '/', float64(1.5)},
{0, 0, '+', 0},
{0, 0, '-', 0},
{0, 0, '*', 0},
{"foo", "bar", '+', "foobar"},
{3, 0, '/', false},
{3.0, 0, '/', false},
{3, 0.0, '/', false},
{uint(3), uint(0), '/', false},
{3, uint(0), '/', false},
{-3, uint(0), '/', false},
{uint(3), 0, '/', false},
{3.0, uint(0), '/', false},
{uint(3), 0.0, '/', false},
{3, "foo", '+', false},
{3.0, "foo", '+', false},
{uint(3), "foo", '+', false},
{"foo", 3, '+', false},
{"foo", "bar", '-', false},
{3, 2, '%', false},
} {
result, err := doArithmetic(this.a, this.b, this.op)
if b, ok := this.expect.(bool); ok && !b {
if err == nil {
t.Errorf("[%d] doArithmetic didn't return an expected error")
}
} else {
if err != nil {
t.Errorf("[%d] failed: %s", i, err)
continue
}
if !reflect.DeepEqual(result, this.expect) {
t.Errorf("[%d] doArithmetic got %v but expected %v", i, result, this.expect)
}
}
}
}
func TestFirst(t *testing.T) { func TestFirst(t *testing.T) {
for i, this := range []struct { for i, this := range []struct {
count int count int