Implement the related character intrinsic functions
SCAN and VERIFY.
Logic looks good to me. Please take care of the Pre-merge checks if they make sense.
Given the logic of the code, the 3 narrowing warnings from clang-tidy do not look harmful to me, but I think it might be worth adding explicit casts/removing the initializer list to avoid compiler warnings here.
Is this clang-format warning coming from a clang-format version difference ?