blob: 4c35ff11ee13d6f61a0aa207ea9639d59db6dd51 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
|
// Copyright 2017, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE.md file.
// Package function identifies function types.
package function
import "reflect"
type funcType int
const (
_ funcType = iota
ttbFunc // func(T, T) bool
tibFunc // func(T, I) bool
trFunc // func(T) R
Equal = ttbFunc // func(T, T) bool
EqualAssignable = tibFunc // func(T, I) bool; encapsulates func(T, T) bool
Transformer = trFunc // func(T) R
ValueFilter = ttbFunc // func(T, T) bool
Less = ttbFunc // func(T, T) bool
)
var boolType = reflect.TypeOf(true)
// IsType reports whether the reflect.Type is of the specified function type.
func IsType(t reflect.Type, ft funcType) bool {
if t == nil || t.Kind() != reflect.Func || t.IsVariadic() {
return false
}
ni, no := t.NumIn(), t.NumOut()
switch ft {
case ttbFunc: // func(T, T) bool
if ni == 2 && no == 1 && t.In(0) == t.In(1) && t.Out(0) == boolType {
return true
}
case tibFunc: // func(T, I) bool
if ni == 2 && no == 1 && t.In(0).AssignableTo(t.In(1)) && t.Out(0) == boolType {
return true
}
case trFunc: // func(T) R
if ni == 1 && no == 1 {
return true
}
}
return false
}
|
