[avitzur]

That thread describes me working through performance issues in the initial port eight months ago. Those cases perform adequately now. Parsing is not a bottleneck. Walking the bytecode remains a performance hotspot, as that is where all the numeric calculations occur, but no more or less so comparing the C++ and Swift implementations.

I did investigate maintaining the flex/bison parser, since its generated state machine C code is more robust than my handwritten recursive descent parser when presented with pathological input. However, as you say, since I need a Swift data structure in the end, there is little to be gained and a lot of complication bridging via a C-FFI.