In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.
This script can be used to spot hammers on the charts, I try to avoid false positives by ignoring candles which have less than 0.25% price difference between open and close.