locality.nx

locality.nx -- data-locality markers + cost estimates. EFFICIENCY_ROADMAP §1.1. Speed of light = 30 cm/ns. Modern memory / network hierarchy looks like: L1 cache ~1 ns reg-adjacent L2 cache ~5 ns L3 cache ~20 ns DRAM (NUMA-local) ~100 ns DRAM (remote) ~150 ns NVMe SSD ~10,000 ns (10 us) CXL tier-3 mem ~500 ns (emerging) Network LAN ~100,000 ns (100 us) Network WAN ~10,000,000 ns (10 ms) Interplanetary ~minutes+ (light-delay bound) NishiLang today can't reason about ANY of this -- every deref looks equal to the type system. Phase B lifts these constants + markers into the type system so hot loops can be flagged when they cross locality boundaries ('remote deref in hot loop' warning, cost-aware codegen). Phase A: runtime descriptors so library code can attach locality tags to its pointers + query / branch on them. Invariants: LC1 Every LocalityTier constant carries a pessimistic- upper-bound latency in nanoseconds. LC2 Ordering is monotonic: tier N implies latency <= tier N+1. LC3 `locality_worse(a, b)` returns the slower of two tiers -- useful when composing operations.