.. This document was generated by tools/gen-cpydiff.py Syntax ====== Generated Fri 29 Mar 2024 10:23:56 UTC .. _cpydiff_syntax_arg_unpacking: Argument unpacking does not work if the argument being unpacked is the nth or greater argument where n is the number of bits in an MP_SMALL_INT. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ **Cause:** The implementation uses an MP_SMALL_INT to flag args that need to be unpacked. **Workaround:** Use fewer arguments. Sample code:: def example(*args): print(len(args)) MORE = ["a", "b", "c"] example( 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, *MORE, ) +-------------+--------------------------------------------+ | CPy output: | uPy output: | +-------------+--------------------------------------------+ | :: | :: | | | | | 67 | Traceback (most recent call last): | | | File "", line 21, in | | | SyntaxError: too many args | +-------------+--------------------------------------------+ Operators --------- .. _cpydiff_syntax_assign_expr: MicroPython allows using := to assign to the variable of a comprehension, CPython raises a SyntaxError. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ **Cause:** MicroPython is optimised for code size and doesn't check this case. **Workaround:** Do not rely on this behaviour if writing CPython compatible code. Sample code:: print([i := -1 for i in range(4)]) +-------------------------------------------------------------------------------------------+-------------------------------------------------+ | CPy output: | uPy output: | +-------------------------------------------------------------------------------------------+-------------------------------------------------+ | :: | :: | | | | | File "", line 7 | Traceback (most recent call last): | | SyntaxError: assignment expression cannot rebind comprehension iteration variable 'i' | File "", line 7, in | | | SyntaxError: identifier redefined as global | +-------------------------------------------------------------------------------------------+-------------------------------------------------+ Spaces ------ .. _cpydiff_syntax_spaces: uPy requires spaces between literal numbers and keywords, CPy doesn't ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Sample code:: try: print(eval("1and 0")) except SyntaxError: print("Should have worked") try: print(eval("1or 0")) except SyntaxError: print("Should have worked") try: print(eval("1if 1else 0")) except SyntaxError: print("Should have worked") +--------------------------------------------------------+------------------------+ | CPy output: | uPy output: | +--------------------------------------------------------+------------------------+ | :: | :: | | | | | 0 | Should have worked | | 1 | Should have worked | | 1 | Should have worked | | :1: SyntaxWarning: invalid decimal literal | | | :1: SyntaxWarning: invalid decimal literal | | | :1: SyntaxWarning: invalid decimal literal | | | :1: SyntaxWarning: invalid decimal literal | | +--------------------------------------------------------+------------------------+ Unicode ------- .. _cpydiff_syntax_unicode_nameesc: Unicode name escapes are not implemented ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Sample code:: print("\N{LATIN SMALL LETTER A}") +-------------+-----------------------------------------------+ | CPy output: | uPy output: | +-------------+-----------------------------------------------+ | :: | :: | | | | | a | NotImplementedError: unicode name escapes | +-------------+-----------------------------------------------+