This is unsafe. Safer would be:

uint8_t idx = (uint8_t)(data[0]);

(at any rate, this is defined). But if you want an unsigned type that is guaranteed to hold all of the values of a char, then you want unsigned char instead of uint8_t.

Thank you, unsigned char makes way more sense, done.

Out of curiosity, why is accessing the element and then casting safer than casting the pointer and then accessing the element?

matching

Import

being pedantic: check re_module for NULL.

pedantic: check sre_compile_module for NULL

the same goes for all of your GetAttrString return values.

NULL check

NULL checks

this series if if's with PyErr_ExceptionMatches calls seems somewhat redundant (the comments for each match type are useful). It can also call PyErr_ExceptionMatches after PyErr_Clear has been called as these are sequential if's not else if's. perhaps write it as:

if (compiled == NULL) {
  if (PyErr_ExceptionMatches(xxx) ||
      PyErr_ExceptionMatches(yyy) ||
      ...) {
  }
}

with the comments interspersed.

Agreed, the comments were primarily why I went with this style but I'll see if I can put them between the ORs.

Done, kinda iffy about the formatting. Got any suggestions?

if (PyErr_ExceptionMatches(xxx) ||
    PyErr_ExceptionMatches(yyy)
    ) {
    PyErr_Clear();
    }
}

and

if (PyErr_ExceptionMatches(xxx) ||
    PyErr_ExceptionMatches(yyy)) {
    PyErr_Clear();
    }
}

both look really confusing, so I went with some alternative style.