our-basic CHANGELOG -- calog's modifications to upstream MY-BASIC
================================================================

Every change below is marked in-source with the comment tag "[calog fork]".
Baseline: ourBasic.c.upstream (pristine upstream MY-BASIC). Run
  diff ourBasic.c.upstream ourBasic.c
to see the full patch set.

Concurrency
  - The _mb_allocated allocation counter was changed from `volatile` to `_Atomic`,
    so independent interpreters (one per calog context thread) can be created and
    destroyed concurrently without racing the counter. Execution already runs
    unlocked; only lifecycle is serialized, in the adapter.

Memory
  - A my-basic routine (lambda) popped as a refused/errored native argument is now
    disposed on the error path so its scope is not leaked. (In the adapter's
    arg-marshal loop, src/mybasic/mybasicAdapter.c.)

First-class routines -- the reason for the fork
  - Bare-def-as-value: in _calc_expression, a routine identifier NOT followed by
    '(' now pushes the routine as an operand (a first-class value) instead of
    raising "Open bracket expected". A script can now pass a `def` (or a lambda) to
    a native and store it in a variable -- required for cross-engine callbacks
    (pubsub / timer / export). It mirrors the array-index branch beside it; calls,
    recursion, and closures are unchanged.
  - mb_eval_routine_cold(): a new public entry (declared in ourBasic.h) that invokes
    a routine value from an IDLE interpreter -- one with no live call frame. It
    supplies the last AST node as a clean return landing and passes arguments
    directly. calog uses it to fire script callbacks that were registered earlier
    and delivered when the interpreter is otherwise idle.

Constraint: a callback must be a TOP-LEVEL def/lambda (persistent scope); a routine
local to a function would dangle once that function returns -- the same rule every
engine's closures follow.

Bare-name resolution for dynamic functions
  - mb_dynamic_func_handler / mb_set_dynamic_func_handler(): a new hook (a field on
    mb_interpreter_t plus its setter, declared in ourBasic.h). In _calc_expression,
    where a bare identifier called like a function -- foo(args) -- that is not a
    variable/routine/collection would raise "Invalid identifier usage", the interpreter
    now first offers the (uppercased) name to the registered handler. The handler
    returns MB_FUNC_OK (handled -- the result is left in the running intermediate
    value), MB_FUNC_IGNORE (unknown -- the normal error is then raised), or an error
    code; the pending argument list is left untouched on IGNORE. calog uses it to
    resolve a bare name to a broker export, so exportedFn(args) works without an
    explicit calogCall -- the same convenience the hook engines have. (The adapter
    resolves case-insensitively, since my-basic uppercases identifiers at parse time.)

Verified: full calog `make test` (28 binaries, 0 failed) plus the my-basic engine
suite (testMyBasic / testEngineMyBasic / testPolyglot / testLoad / testTask),
ASan/UBSan-clean, with def and lambda callbacks firing via timer/pubsub/export and
cross-engine (a Lua task calling a my-basic def).

Portability -- number classification does not trust endptr alone
  - `_get_symbol_type` (and VAL / INPUT) decided "this symbol is a number" from
    strtoll/strtod alone reaching the string terminator. That test is not portable:
    musl's strtoll ADVANCES endptr past leading whitespace and a sign even when no
    conversion happens, where glibc leaves endptr at the start. On musl this made
    "+" and "-" -- the operators -- and "\n" -- the statement separator -- each
    classify as the integer 0, so every expression containing an operator failed to
    parse and every numeric assignment failed to run, both with "Operator expected".
    A new `_conv_matched_nothing(start, end)` rejects a consumed span that is nothing
    but whitespace and sign; a span that consumed anything else (digits, "inf",
    "nan") classifies exactly as before, on every libc, and an empty span is left
    alone so VAL("")/INPUT with an empty line keep their existing behavior.
    Reproduced with a pure my-basic program (no calog code): `x = 1` returned
    MB_FUNC_ERR on musl and MB_FUNC_OK on glibc.

Verified: testEngineMyBasic 20/20 on a fully static musl build via zig (was 13 of 20
failing), unchanged 20/20 natively, and calog `make test` 943 checks / 0 failed.