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| -rw-r--r-- | README.md | 17 |
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@@ -130,6 +130,23 @@ Testing for these grammar files (other than `builtins`) is iffy at this point, so use at your own risk! These grammar files are only approximations of syntax. +## Performance + +Currently, `bp` is super slow compared to hyper-optimized regex tools like +`grep` and `ripgrep`. `bp` is **not** matching regular expressions, so this is +not strictly a fair comparison. By definition, regular expressions can be +implemented using finite state machines, which are very efficient. Most regex +tools also add the additional restriction that matches must be within a single +line. `bp` on the other hand, uses parsing expression grammars, which can match +arbitrarily complicated or nested structures, requiring a dynamic call stack +and potentially unbounded memory use. This makes `bp` patterns much more +expressive, but harder to optimize. At this point in time, `bp`'s +implementation also uses a fairly naive virtual machine written in C, which is +not very heavily optimized. As a result, `bp` runs quite fast over thousands of +lines of code, reasonably fast over tens of thousands of lines of code, and +pretty slow over millions of lines of code. + + ## License BP is provided under the MIT license with the [Commons Clause](https://commonsclause.com/) |