Understanding web3.eth.filter parameters

Question

I have been looking through that web3.eth.filter function, and ran into a bit of a wall:

var options = {
  fromBlock: "pending",
  toBlock: "latest",
  address: "0xab1323fe3234234234fa34324324234af3423432",
};
var filter = web3.eth.filter(options);

in regards to the "pending" and "latest" strings, this is the definition I got from github:

latest may be given to mean the most recent and pending currently mining, block

source: https://github.com/ethereum/wiki/wiki/JavaScript-API#web3ethfilter

QUESTION:

What does that actually mean? If I run geth for instance and there are a bunch of blocks pending to be added to the blockchain, lets imagine each "-" represents 1 block in the following example:

- - - - - - - - -

If I had fromBlock: "pending" to toBlock: "latest", would that mean the following:

(start here) - - - - - - - - - (end here)

But if that were the case, there would be more blocks added by the time the end is reached:

(start here) - - - - - - - - - (end here) - -

So would latest mean continue forever or stop on the one that was the latest when the filter was actually created ?

Answer 1

The term latest "dynamically updates". That's why if you call web3.eth.filter(...).watch() you'll find new logs added. At least, this is what I see using testrpc. You may experience delays on the mainnet.