User can override PYTHON executable before running script,
gen-cpydiff.py works only with Python3 and most systems register
its executable as 'python3'.
I also didn't see any real reason for mkrules.mk to exist,
so I merged the contents into Makefile.
Now you can do:
```
make BOARD=pca10028 clean
make BOARD=pca10028 flash
```
and it will work properly.
In this case, raise an exception without a message.
This would allow to shove few code bytes comparing to currently used
mp_raise_msg(..., "") pattern. (Actual savings depend on function code
alignment used by a particular platform.)
In MicroPython, the path separator is guaranteed to be "/", extra unneeded
things take precious code space (in the port which doesn't have basic things
like floating-port support).
The parser was originally written to work without raising any exceptions
and instead return an error value to the caller. But it's now required
that a call to the parser be wrapped in an nlr handler, so we may as well
make use of that fact and simplify the parser so that it doesn't need to
keep track of any memory errors that it had. The parser anyway explicitly
raises an exception at the end if there was an error.
This patch simplifies the parser by letting the underlying memory
allocation functions raise an exception if they fail to allocate any
memory. And if there is an error parsing the "<id> = const(<val>)" pattern
then that also raises an exception right away instead of trying to recover
gracefully and then raise.
Previous to this patch any non-interned str/bytes objects would create a
special parse node that held a copy of the str/bytes data. Then in the
compiler this data would be turned into a str/bytes object. This actually
lead to 2 copies of the data, one in the parse node and one in the object.
The parse node's copy of the data would be freed at the end of the compile
stage but nevertheless it meant that the peak memory usage of the
parse/compile stage was higher than it needed to be (by an amount equal to
the number of bytes in all the non-interned str/bytes objects).
This patch changes the behaviour so that str/bytes objects are created
directly in the parser and the object stored in a const-object parse node
(which already exists for bignum, float and complex const objects). This
reduces peak RAM usage of the parse/compile stage, simplifies the parser
and compiler, and reduces code size by about 170 bytes on Thumb2 archs,
and by about 300 bytes on Xtensa archs.
This patch allows uPy consts to be bignums, eg:
X = const(1 << 100)
The infrastructure for consts to be a bignum (rather than restricted to
small integers) has been in place for a while, ever since constant folding
was upgraded to allow bignums. It just required a small change (in this
patch) to enable it.
socket.timeout is a subclass of OSError, and using the latter is more
efficient than having a dedicated class. The argument of OSError is
ETIMEDOUT so the error can be distinguished from other kinds of
OSErrors. This follows how the esp8266 port does it.
Since we recently replaced the OSError string messages with simple error
codes, having the uerrno module gets back some user friendly error
messages. The total code size (after removing strings, replacing with
uerrno module) is decreased.
It's configured by MICROPY_PY_UERRNO_ERRORCODE and enabled by default
(since that's the behaviour before this patch).
Without this dict the lookup of errno codes to strings must use the
uerrno module itself.
