Merge pull request #3295 from tinmarino/merge_index_regex

Feature: Index regex interpolation tokens

Author: JJ

doc/Language/regexes.pod6

@@ -1187,7 +1187,7 @@ There are two variants: lookahead and lookbehind assertions.
 Technically, anchors are also zero-width assertions, and they can look
 both ahead and behind.
 
-=head2 X«Lookaround assertions|regex,positive lookaround assertion;regex,negative lookaround assertion»
+=head2 X«Lookaround assertions|regex,positive lookaround assertion, <?>;regex,negative lookaround assertion, <!>; regex ?[ »
 
 Lookaround assertions work both ways. They match, but they don't consume a
 character.
@@ -1219,7 +1219,7 @@ negative lookaround assertion behaves in the same way. In the fourth
 statement the last digit is matched but not consumed, thus the match includes
  only the first two digits.
 
-=head2 X<Lookahead assertions|regex,before>
+=head2 X«Lookahead assertions|regex, before;regex, <?before>»
 
 To check that a pattern appears before another pattern, use a
 lookahead assertion via the C<before> assertion. This has the form:
@@ -1269,7 +1269,7 @@ that are followed by a unit (like I<kg>), but not other numbers:
 Since the lookahead is not part of the match object, the unit
 is not substituted.
 
-=head2 X<Lookbehind assertions|regex,after>
+=head2 «Lookbehind assertions|regex, after; regex, <?after>»
 
 To check that a pattern appears after another pattern, use a
 lookbehind assertion via the C<after> assertion. This has the form:
@@ -1894,6 +1894,7 @@ pattern, which may be summarized as follows:
 
 =end table
 
+X<|regex, $variable>X<|regex, $(code)>
 Let's start with the first two syntactical forms: C«$variable» and C«$(code)».
 These forms will interpolate the stringified value of the variable or the
 stringified return value of the code literally, provided that the respective
@@ -1969,6 +1970,7 @@ interpolation. Hence, in general, after possible stringification, C«$variable»
 and C«$(code)» provide for a strictly literal match of the variable or return
 value.
 
+X«|regex, <$variable>»X«|regex, <{code}>»
 Now consider the second two syntactical forms from the table above:
 C«<$variable>» and C«<{code}>». These forms will stringify the value of the
 variable or the return value of the code and interpolate it as a regex. If the
@@ -2019,6 +2021,7 @@ The use of hashes in regexes is reserved.
 
 =head2 Regex boolean condition check
 
+X«|regex, <?{}>;regex, <!{}>»
 The special operator C«<?{}>» allows the evaluation of a boolean expression that
 can perform a semantic evaluation of the match before the regular expression
 continues. In other words, it is possible to check in a boolean context a part