The thing is you don&#x27;t know what&#x27;s going to be slow and you can&#x27;t realistically test various implementations for every functions. IMHO a better strategy is to code using standard libraries and use a good profiler. Maybe the tokenizer could be faster, but something else might be 100x slower so it&#x27;d be better to optimize the other thing first anyway.<p>Also, sometimes the best performance comes when reevaluating the whole way to do something. Consider your example about wasting time on tokens. Maybe a better way to optimize the build time is to create the compilers so it receives &quot;diffs&quot; rather than all files every time.