go-iota-with-bit-shift-operator

what is << iota in Go

tags: learning go programming

content

• in go-bitmask-check, im seeing this code:

type RowLineFlags int
const (
	Revision RowLineFlags = 1 << iota
	Highlightable
	Elided
)

• what does << iota do?
  • this is iota with bit shift operator << to create a set of flags with distinct bit patterns
  • 1 << iota means the flags only has one bit turned on
    • it’s a constant with a single bit turned on, like 0x01, 0x02, 0x04, etc
    • i.e.: in binary

Revision = 0001 (binary)
Highlightable = 0010 (binary)
Elided = 0100 (binary)

• and in decimal

Revision = 1
Highlightable = 2
Elided = 4

up

• go-iota

down

reference