Question about code

[Hang95]

Hi,sorry to bother you. I'm new to Golang and try to learn the language through your code. I notice that when using values in a struct, like

type Block struct {
	hash     Hash
	parent   Hash
	proposer hotstuff.ID
	cmd      Command
	cert     QuorumCert
	view     View
}

the code defined a method

func (b *Block) Hash() Hash {
	return b.hash
}

to return it instead of directly using Block.hash. Why to use it this way?
Thank you so much.

[johningve]

Hi!

There are a few reasons to do this in Go:

1. To make a field immutable (at least to other packages)
2. To be able to use it in an interface

As for Block.Hash(), the main reason is to make the hash field immutable. Also, the Hash() method was previously used to calculate the hash the first time it was called, but I moved that to NewBlock.

[Hang95]

Thank you!