This is rarely used feature which takes enough code to implement, so is
controlled by MICROPY_PY_ARRAY_SLICE_ASSIGN config setting, default off.
But otherwise it may be useful, as allows to update arbitrary-sized data
buffers in-place.
Slice is yet to implement, and actually, slice assignment implemented in
such a way that RHS of assignment should be array of the exact same item
typecode as LHS. CPython has it more relaxed, where RHS can be any sequence
of compatible types (e.g. it's possible to assign list of int's to a
bytearray slice).
Overall, when all "slice write" features are implemented, it may cost ~1KB
of code.
This makes exception traceback info self contained (ie doesn't rely on
list object, which was a bit of a hack), reduces code size, and reduces
RAM footprint of exception by eliminating the list object.
Addresses part of issue #1126.
The implementation of these functions is very large (order 4k) and they
are rarely used, so we don't enable them by default.
They are however enabled in stmhal and unix, since we have the room.
Most of printing infrastructure now uses streams, but mp_obj_print() used
libc's printf(), which led to weird buffering issues in output. So, switch
mp_obj_print() to streams too, even though it may make sense to move it to
a separate file, as it is purely a debugging function now.
Relative imports are based of a package, so we're currently at a module
within a package, we should get to package first.
Also, factor out path travsering operation, but this broke testing for
boundary errors with relative imports. TODO: reintroduce them, together
with proper tests.
Traceback allocation for exception will now never lead to recursive
MemoryError exception - if there's no memory for traceback, it simply
won't be created.
Pushing same NLR record twice would lead to "infinite loop" in nlr_jump
(but more realistically, it will crash as soon as NLR record on stack is
overwritten).
Previous to this patch, a big-int, float or imag constant was interned
(made into a qstr) and then parsed at runtime to create an object each
time it was needed. This is wasteful in RAM and not efficient. Now,
these constants are parsed straight away in the parser and turned into
objects. This allows constants with large numbers of digits (so
addresses issue #1103) and takes us a step closer to #722.
