Parsing is only the start

aihc-parser is about 1.8× as fast as GHC’s parser on this M4 Pro MacBook: 12.8 MB/s versus GHC’s 7.2 MB/s in our Stackage benchmark. The parser is sprinting. The type-checker still has most of the track to itself.

We spend far more time type-checking than parsing, so Amdahl’s law remains unimpressed. If parsing were 10% of a build, this speedup would shave off 4.3% overall. A nice saving. No coffee break cancelled. That 10% is an illustration, not a measured breakdown of AIHC.

Still, every stage gets a stopwatch. A fast parser keeps parsing out of the way, and today’s small costs become tomorrow’s bottlenecks as the rest improves. We’ll take 1.8×. For fast compilation, the type-checker needs to join the race.