list.sort(key=...) (the in-place METHOD) is missing — sorted() works fine

rows = [(1, 3), (2, 1), (3, 2)]
rows.sort(key=lambda r: r[1])
print(rows)

error: Nil Python: TPyList has no method sort

Found 2026-07-31 while re-verifying [[feature-nilpy-lambda]] (closed — real lambda values already work). The standalone sorted(rows, key=lambda r: r[1]) FUNCTION already works correctly (diffed against CPython, matches exactly) — this is specifically the in-place .sort() METHOD on TPyList that has no implementation at all, not a lambda/key= problem.

Shape of a fix

sorted()'s own implementation (pyeval.pas has a sorted(l: TPyList; key: Pointer = nil; reverse: Boolean = False): TPyList per this session's earlier reading of that file) already does the real work — an in-place .sort() should be a thin wrapper: call the same comparison/key logic but write the result back into the SAME TPyList instead of returning a new one (Python's list.sort() returns None and mutates in place, unlike sorted()).

Partially fixed (this session) — plain .sort() only

Added TPyList.sort (pylib.pas) as a genuine method — no-key insertion sort using pyvar_gt, mutating Self in place (confirmed: a second reference to the same list object sees the sort, matching Python's identity guarantee). Diffed against CPython for both numbers and strings; exact match.

key=/reverse= NOT done: the original "shape of a fix" assumption (thin wrapper around sorted()) turned out not to work — sorted()'s key= dispatch goes through PyCallKey1, which lives in pyeval.pas, and pyeval uses pylib (not the reverse), so pylib.pas cannot call back into it. A real key=/reverse= implementation needs either moving the generic-callable-invoke primitive down into pylib.pas (shared by both units) or a frontend-level rewrite of .sort(key=...) into a build-then- swap sequence around the existing sorted() — either is more than this pass's scope. xs.sort(key=...) still fails to PARSE (a compile error, not a crash — sort genuinely takes no parameters today), which is the safe direction to fail in the meantime.

Gate

make test-nilpy + self-host byte-identical, plus .sort() with no key, with key=lambda, and with reverse=True, diffed against CPython — and confirm the list identity is preserved (same object, mutated) the way Python's own .sort() guarantees.