57. Pooling the Scratch Memory of Whole-Input Parses

• Each Parse allocated the decoded input and its offset table, the memo table (slots, entry chunks, the bit set of first calls) and the stack that collects repetition values, and dropped them when it returned: nothing in a result refers to them (node text slices the input string, errors are built before returning). A Program now keeps them in a sync.Pool (acquirePooledParser, releaseScratch): the memo's slots and entry chunks are cleared and reused, and buffers over 4M elements are not kept. Recognition uses its program's pool. Document and streams keep their own memory as before.
• Effect (min of 6 interleaved runs, Apple M3 Max, code points): full parses −1% to −8% (Minilang −8%/−7%/−6% on the three backends, XML −6%/−5%/−4%, JSON −2%/−1%/−1%), allocation −14% to −38% (Minilang 15.3 → 9.5 MB); recognition −5% to −11% (Arith_LeftRec −11%, 24.7 → 3.4 MB).