github.com/modern-go/reflect2@v1.0.2/README.md (about)

     1  # reflect2
     2  
     3  [![Sourcegraph](https://sourcegraph.com/github.com/modern-go/reflect2/-/badge.svg)](https://sourcegraph.com/github.com/modern-go/reflect2?badge)
     4  [![GoDoc](http://img.shields.io/badge/go-documentation-blue.svg?style=flat-square)](http://godoc.org/github.com/modern-go/reflect2)
     5  [![Build Status](https://travis-ci.org/modern-go/reflect2.svg?branch=master)](https://travis-ci.org/modern-go/reflect2)
     6  [![codecov](https://codecov.io/gh/modern-go/reflect2/branch/master/graph/badge.svg)](https://codecov.io/gh/modern-go/reflect2)
     7  [![rcard](https://goreportcard.com/badge/github.com/modern-go/reflect2)](https://goreportcard.com/report/github.com/modern-go/reflect2)
     8  [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://raw.githubusercontent.com/modern-go/reflect2/master/LICENSE)
     9  
    10  reflect api that avoids runtime reflect.Value cost
    11  
    12  * reflect get/set interface{}, with type checking
    13  * reflect get/set unsafe.Pointer, without type checking
    14  * `reflect2.TypeByName` works like `Class.forName` found in java
    15  
    16  [json-iterator](https://github.com/json-iterator/go) use this package to save runtime dispatching cost.
    17  This package is designed for low level libraries to optimize reflection performance.
    18  General application should still use reflect standard library.
    19  
    20  # reflect2.TypeByName
    21  
    22  ```go
    23  // given package is github.com/your/awesome-package
    24  type MyStruct struct {
    25  	// ...
    26  }
    27  
    28  // will return the type
    29  reflect2.TypeByName("awesome-package.MyStruct")
    30  // however, if the type has not been used
    31  // it will be eliminated by compiler, so we can not get it in runtime
    32  ```
    33  
    34  # reflect2 get/set interface{}
    35  
    36  ```go
    37  valType := reflect2.TypeOf(1)
    38  i := 1
    39  j := 10
    40  valType.Set(&i, &j)
    41  // i will be 10
    42  ```
    43  
    44  to get set `type`, always use its pointer `*type`
    45  
    46  # reflect2 get/set unsafe.Pointer
    47  
    48  ```go
    49  valType := reflect2.TypeOf(1)
    50  i := 1
    51  j := 10
    52  valType.UnsafeSet(unsafe.Pointer(&i), unsafe.Pointer(&j))
    53  // i will be 10
    54  ```
    55  
    56  to get set `type`, always use its pointer `*type`
    57  
    58  # benchmark
    59  
    60  Benchmark is not necessary for this package. It does nothing actually.
    61  As it is just a thin wrapper to make go runtime public. 
    62  Both `reflect2` and `reflect` call same function 
    63  provided by `runtime` package exposed by go language.
    64  
    65  # unsafe safety
    66  
    67  Instead of casting `[]byte` to `sliceHeader` in your application using unsafe.
    68  We can use reflect2 instead. This way, if `sliceHeader` changes in the future,
    69  only reflect2 need to be upgraded.
    70  
    71  reflect2 tries its best to keep the implementation same as reflect (by testing).