How do regular expressions work behind the scenes (at the CPU level)?

Question

Do interpreters and compilers compare (and ultimately match) two strings for a potential match in a character-by-character and left-to-right fashion? Or is there an underlying

Answer 1

Regular expressions don't specify implementation details. It's up to the language to decide the best way to compile them to machine code. For example, this regex.c implementation looks like it goes more than one character at a time.