Cx Dev Log — 2026-05-25

The interpreter's variable lookup is now blazing through arithmetic loops at a 57% faster pace. But this isn't just about raw speed — four tracker items were checked off the list, culminating in a more robust system. All rolled out on submain, a direct result of a thorough four-pillar audit. BindingId replaces string hashing at runtime The heavyweight change came from tracker #009. Previously, our interpreter was busy hashing variable names every time they were accessed. That was a repeat offender in wasted cycles. Now, by using a pre-assigned numeric BindingId, we seize efficiency. The semantic phase was already handing out these IDs, but the runtime kept adding the overhead back. It doesn’t anymore. ScopeFrame.vars has transitioned to a HashMap equipped with a zero-cost identity hasher keyed by u32 binding IDs. Name-based lookups are still around but tucked away for less frequent operations like string interpolation. Fixes were necessary upstream: ConstDecl and semantic_impls now hold onto their BindingId, making sure our semantic phase pipelines gracefully into the interpreter's primary key system — narrowing the gap with JIT's variable handling. Here's how the numbers shine on a Windows release build: arith_loop (5M iterations): from 5744ms down to 2481ms (56.8% boost) nested_loops (4M iterations): from 2675ms down to 1796ms (32.8% boost) fib_recursive: from 6835ms down to 6488ms (merely 5.1% faster due to call-frame constraints) Our findings align with expectations: recursive functions aren't bogged down by variable lookups as much as by setting up call frames. Array bounds errors stop lying Misleading diagnostic labels are on their way out, thanks to tracker #002 and #032. Attempts to access out-of-bounds array indices once triggered an error as unhelpful as variable 'index 5' has not been declared . Not anymore. Changes came in two waves. First, we introduced a new error variant: RuntimeError::IndexOutOfBounds { pos, index, length } . Then, three runtime.rs c