How to workaround a port not supporting complex numbers ?

[Josverl]

When running though a test suite ran into an issue that I did not notice on other boards.
It appaers that complex numbers are not supported on the default build for the WIO Terminal.

def foo_complex():
    return 54 + 55j

fails with SyntaxError: complex values not supported 

So now I learned that this is an optional feature , and want to change my tests accordingly.
But I can't even catch the exception in code , as the error is thrown before the code is actually run.
The following still results in the same error:

try:

    def foo_complex():  # type: ignore
        return 54 + 55j

except:
    # complex numbers are not supported on all ports/boards
    def foo_complex():
        return "MICROPY_PY_BUILTINS_COMPLEX=0"

Any suggestions on a workaround or way to detect this (without access to the source that the firmware was compiled from)
Also: is there a specific reason this is not enabled on the WIO terminal ?

{ 'family': 'micropython',
 'version': '1.22.0',
 'port': 'samd',
 'mpy': 'v6.2',
 'build': '',
 'cpu': 'SAMD51P19A',
 'board': 'Wio Terminal D51R with SAMD51P19A',
 'arch': 'armv7emsp',
}

[mendenm]

can you try to do:

try:
    complex(1,0)
except:
    #no complex numbers 

using function syntax, for the complex instead of direct numerical syntax? I don't have a suitable platform to test this on, so I cannot guarantee it will work.

[rkompass]

Also: Can you try to import a small file with the above definition?
I.e.:

try:

    import my_complex_def

except:
    # complex numbers are not supported on all ports/boards
    def foo_complex():
        return "MICROPY_PY_BUILTINS_COMPLEX=0"

[Josverl]

KISS - I like the simplicity of the solution which also also can be read & understood without needing to inspect yet another file

Thanks @mendenm

[robert-hh]

Also: is there a specific reason this is not enabled on the WIO terminal ?

Support for complex numbers is not enabled on the SAMD port. Since you build your firmware yourself you can easily enable it. In mcu/samd51/mpconfigmcu.h the flags for it are included for best visibility. Just set them to 1 and build. It adds about 2.5 k to the flash size. So it could be enabled for SAMD51, maybe not for SAMD21.

Edit: The method @mendenm suggests works.

[robert-hh]

Since today's update of the repository, the flag for enabling MICROPY_PY_BUILTINS_COMPLEX was moved to mpconfigport.h. It disables MICROPY_PY_BUILTINS_COMPLEX, while usually it is enabled when float is supported.

[rkompass]

With a file imp_complex.py on the file system:

def foo_complex():  # type: ignore
    return 54 + 55j

and

try:
    import imp_complex
    MICROPY_PY_BUILTINS_COMPLEX=1

except:
    # complex numbers are not supported on all ports/boards
    MICROPY_PY_BUILTINS_COMPLEX=0

the exception mechanism works and one can test the builtin capabilities.

---

Nice:
This also works with e.g. a file imp_xtensa.py on an esp32 (which does not have asm_xtensa working)

# --- internal ---
# a6 .. idx or tab[idx]
# --- arguments ---
# a5 .. lookup table address
# a4 .. n (length of data), then data address + n
# a3 .. data address
# a2 .. crc
@micropython.asm_xtensa
def _crc8_tr(a2, a3, a4, a5) -> uint:
    add(a4, a4, a3)    # final data address
    label(loop)
    l8ui(a6, a3, 0)    # a6 = idx = data[0]
    addi(a3, a3, 1)    # increment data pointer
    xor(a6, a6, a2)    # idx ^= crc
    add(a6, a6, a5)    # table data address
    l8ui(a2, a6, 0)    # fetch table entry: a2 = tab[idx]
    bne(a3, a4, loop)  # --- test and outer end ---

and

try:
    import imp_xtensa
    able_xtensa = True
except:
    able_xtensa = False

which solves the problem of testing which decorators for higher speed may be used.

This solves/closes issue 11805

[Josverl]

Thanks to all that pitched in a collection of detection methods of optional functionality, all in a single file :

https://github.com/Josverl/micropython-magic/blob/main/samples/detect_optional_features.ipynb

The format is a Jupyter notebook, be able to see the code and results of the last run, but can run as '.py' code as well.