Parsing Advances

Summary

Parsing Advances Dec 28, 2025 I find myself writing yet another toy parser, as one does during a Christmas break. It roughly follows Resilient LL Parsing Tutorial. Not because I need resilience, but mostly because I find producing a syntax tree and a collection of diagnostics a more natural fit for the problem than bailing out on the first error. One practical pitfall with the approach is infinite loops/recursion. Resilience sometimes means not consuming a token, and, if you do that in a loop or a Pratt recursive call, you’ll get yourself an annoying to debug error: running 1 test from ./src/corpus_test.ts corpus ...Task test deno test --allow-read=./src/corpus --allow-write=./src/corpus "--" "--update" Check src/corpus_test.ts <--- Last few GCs ---> 4,[26641:0x9d1574000] 7390 ms: Mark-Compact (reduce) 3924.9 (3927.3) -> 3924.9 (3926.3) MB, pooled: 0.0 MB, 1224.00 / 0.00 ms (+ 0.3 ms in 1 steps since start of marking, biggest step 0.3 ms, walltime since start of marking 1232 ms) (average mu = 0.200,[26641:0x9d1574000] 8804 ms: Mark-Compact (reduce) 4009.9 (4011.3) -> 4009.9 (4011.3) MB, pooled: 0.0 MB, 1294.67 / 0.00 ms (+ 0.2 ms in 1 steps since start of marking, biggest step 0.2 ms, walltime since start of marking 1302 ms) (average mu = 0.141, # # Fatal JavaScript out of memory: Ineffective mark-compacts near heap limit # ==== C stack trace =============================== 0 deno 0x0000000102ce8404 v8::base::debug::StackTrace::StackTrace() + 24 1 deno 0x0000000102ceeb9c v8::platform::(anonymous namespace)::PrintStackTrace() + 24 2 deno 0x0000000102ce4094 v8::base::FatalOOM(v8::base::OOMType, char const*) + 68 3 deno 0x0000000102d3a7a8 v8::internal::V8::FatalProcessOutOfMemory(v8::internal::Isolate*, char const*, v8::OOMDetails const&) + 296 4 deno 0x0000000102f37378 v8::internal::Heap::stack() + 0 5 deno 0x0000000102f3581c v8::internal::Heap::CheckMemoryPressure() + 0 6 deno 0x0000000102ead4f8 v8::internal::StackGuard::HandleInterrupts(v8::internal::StackGuard::Int...