xs.sort(key=..., reverse=...) — only the free function sorted() supports key/reverse

Found by proactive CPython-diff sweeping.

data = [("a", 3), ("b", 1), ("c", 2)]
data.sort(key=lambda t: t[1])
print(data)

CPython sorts in place: [('b', 1), ('c', 2), ('a', 3)]. pxx: compile error —

pascal26:2: error: unexpected token
  near:   data  sort  >>> key  lambda

sorted(l, key=..., reverse=...) (the free function) already works — implemented in compiler/builtin/pyeval.pas, NOT pylib.pas, specifically because invoking the key CALLABLE needs pyeval's closure-dispatch machinery (pycall_value/PyCallKey1-style dispatch mentioned in that file's own comments). TPyList.sort (the in-place instance method, declared on TPyList in compiler/builtin/pylib.pas) only has the bare function sort: TPyList; overload — no key/reverse params — because pylib.pas is loaded (and usesd) BEFORE pyeval.pas, so it has no visibility into the callable-dispatch machinery a key= implementation needs.

Fix direction

Since TPyList can't gain a same-named overload from a LATER unit (Pascal doesn't reopen a class across units the way a class helper elsewhere might), the natural fix mirrors how the free function already exists: add a plain function in pyeval.pas — e.g. pylist_sort_inplace(l: TPyList; key: Pointer; reverse: Boolean) — that calls the SAME sort logic sorted() uses but writes the result back into l in place (clear + refill, or an in-place swap-based sort) rather than returning a new list. Then wire xs.sort(key=..., reverse=...) in the frontend (compiler/pyparser.inc's method-call dispatch) to recognize this specific method+kwarg shape and call that free function instead of the bare TPyList.sort method — the same "method call dispatches to a free pylib function" pattern already used elsewhere in this frontend (e.g. str methods route through PyParseStrMethod to plain pystr_* functions, not genuine AnsiString methods).

Not attempted this pass — needs a new parser dispatch branch plus a pyeval.pas addition, more scope than a quick patch mid-sweep; the plain xs.sort() (no key) and sorted(xs, key=..., reverse=...) both already work, so this is specifically the in-place-method + key/reverse combination.

Gate

A .npy case with .sort(), .sort(reverse=True), .sort(key=lambda...), and .sort(key=..., reverse=True), diffed against CPython (checking the mutation is genuinely in place, not just a return value), gated in test-nilpy + --tier quick + self-host byte-identical.