An example of iota in the Go language

This is a created article in which the information may have evolved or changed.

package mainimport (    "fmt")type BitFlag intconst (    // iota为0，1左移0位 = 1    Active BitFlag = 1 << iota    // Send <=> Active <=> 1 << iota，此时iota为1，1左移1位 = 2    Send    // Receive <=> Send <=> 1 << iota，此时iota为2，1左移2位 = 4    Receive)func main() {    fmt.Println(Active, Send, Receive)}

Iota is at compile time, the compiler is dynamically replaced by the position of the iota in the code and the Const keyword.

package mainimport (    "fmt")const (    //e=0,f=0,g=0    e, f, g = iota, iota, iota)func main() {    fmt.Println(e, f, g)}

Iota can be understood as the row index of a const statement

package mainimport (    "fmt")func main() {    fmt.Println(iota)}

Compilation error: Undefined:iota.

Iota are pre-declared identifiers, but only in const constant declarations.
How do I feel iota this thing is a go bastard, can only be locked in a place, unlike True/false and other brothers, cannot access it.