4.3.1. Transaction Receipt-Yellow Paper

Question

I am trying to understand the following function which appears in section 4.3.1 of the Ethereum Yellow Paper:

The function description state it "prepares" a transaction receipt, does it mean that the function does not actually perform the RLP encoding?. What is the purpose of this function?. Any pointers would be great,thanks in advance.

Answer 1

It is what you say the function doesn't actually perform the RLP encoding. The function is just transform a transaction receipt into a new list contain:

• 0: The constant 0
• Ru: the cumulative gas
• Rb: Bloom filter composed
• Rl: the set of logs

This function is just like what they call it prepare to be transform into RLP-serialize. If you look up ahead at this function:

Ht ≡ TRIE({∀i < ||BT||, i ∈ N : p(i, LT (BT[i]))})

p(k, v) ≡ (RLP(k), RLP(v))

Now you can easily understand that LT(BT[i]) mean the prepare for the RLP-serialize for each receipt in BT and then the function p use RLP-encode on it.

If they didn't define that earlier the function will be a lot uglier than it is (which is already very ugly).