^start of string
while the literal text while (case sensitive) Group 1((?=\S)[1di\W]|an|eval|nput|nt|or|pr){55} {55}repeats the group contents below exactly 55 times:
1st Alternative(?=\S)[1di\W] \Sany non-whitespace character
1the literal 1 (4910 / 618 / 3116)
dthe literal d (10010 / 1448 / 6416) (case sensitive)
ithe literal i (10510 / 1518 / 6916) (case sensitive)
\Wany non-word character
anthe literal text an (case sensitive) evalthe literal text eval (case sensitive) nputthe literal text nput (case sensitive) ntthe literal text nt (case sensitive) orthe literal text or (case sensitive) prthe literal text pr (case sensitive) sthe literal s (11510 / 1638 / 7316) (case sensitive)
(?1){45}calls group 1 as a subroutine, repeated exactly 45 times
nthe literal n (11010 / 1568 / 6E16) (case sensitive)
.any character (except for line terminators)
.any character (except for line terminators)
.any character (except for line terminators)
$end of string, or before its final line terminator
g modifier: global. Finds all matches instead of stopping after the first