“使用Go语法安全地转义”是什么意思？

Question

Go's fmt package defines %q (for strings) as:

 %q      a double-quoted string safely escaped with Go syntax

What does safely escaped with Go syntax mean?

Some experimentation shows it preserves escape sequences used in the original string:

s := "This has \"quotes\" in it"
fmt.Printf("%q
", s)             // output: "This has \"quotes\" in it"

Is there anything else it does? In what situations might you want to use this? I'm guessing perhaps in templates that generate Go code?

Answer 1

It means that the formatted output would be escaped properly that it can be copied and used in the go source code

Example formattings

 "abc"          => `"abc"`
 []byte("abc")  => `"abc"`
 ""             => `""`
 "\""           => `"\""`
 `
`           => `"\
"`
 renamedBytes([]byte("hello")) => `"hello"`
 []renamedUint8{'h', 'e', 'l', 'l', 'o'} => `"hello"`
 reflect.ValueOf("hello") => `"hello"`

Code explaining the above

package main

import (
    "fmt"
    "reflect"
)

func main() {
    type renamedBytes []byte
    type renamedUint8 uint8

    fmt.Printf("%q
", "abc")
    fmt.Printf("%q
", []byte("abc"))
    fmt.Printf("%q
", "
")
    fmt.Printf("%q
", []renamedUint8{'h', 'e', 'l', 'l', 'o'})
    fmt.Printf("%q
", renamedBytes([]byte("hello")))
    fmt.Printf("%q
", reflect.ValueOf("hello"))
}