A couple of small suggestions. Change:
| ^ REGEX METACHARS REGEX MODIFIERS
&& ^ string begin /i case insens.
|| $ str. end (before \n) /m line based ^$
.. ... + one or more /s . includes \n
?: * any amount /x ign. wh.space
= += -= *= etc. ? zero or one /g global</b>
, => () capture
list ops (?:) no capture REGEX CHARCLASSES
not [] character class . == [^\n]
and | alternation \s == [\x20\f\t\r\n]
or xor {1,2} amount \w == [A-Za-z0-9_]
\b word boundary \d == [0-9]
\z string end \S, \W and \D negate
to:
| ^ REGEX METACHARS REGEX MODIFIERS
&& ^ string begin /i case insens.
|| $ str. end (before \n) /m line based ^$
.. ... + one or more /s . includes \n
?: * zero or more /x ign. wh.space
= += -= *= etc. ? zero or one /g global
, => {3,7} repeat in range
list ops () capture REGEX CHARCLASSES
not (?:) no capture . == [^\n]
and [] character clas \s == [\x20\f\t\r\n]
or xor | alternation \w == [A-Za-z0-9_]
\b word boundary \d == [0-9]
\z string end \S, \W and \D negate