"single regex" is relative in Perl since you can include Perl-code investigating a sub-match

Does it must be a single regex, or is it just academic curiosity?

edit

you need a positive condition which allows to stop the non-greedy only if you have a match or you reached the end.

  DB<113> print join "|",'a<b1<b2' =~ /(a).+?(?:(c.)|$)/
a|

  DB<114> print join "|",'a<b1<c2' =~ /(a).+?(?:(c.)|$)/
a|c2

  DB<115> print join "|",'a<c1<c2' =~ /(a).+?(?:(c.)|$)/
a|c1
[download]

Try to apply this technique.

HTH

More like a perverse obsession.

Thanks for your tip on "use re 'debug'".

It shows that the RE gets confounded by the <Unwanted> tag.
Removing that tag allows the regex to capture both items I want.

However, this is not an option while I'm parsing the log.

                All power corrupts, but we need electricity.

my proposition from the edit here works for me with your data:

  
  DB<132> p $x
<blah1 phase="2" type="MyType" more_keys="Values" <Unwanted/>  <SomeTa
+gIwant><k1="v1"></SomeTagIwant>

  DB<133> $re = qr/\btype="([^"]+)".+?<(\w+TagIwant\b|$)/


  DB<134> print join "|", $x =~ $re
MyType|SomeTagIwant
[download]

update

  DB<154> p $x
<blah1 phase="2" type="MyType" more_keys="Values" <Unwanted/>  <SomeTa
+gIwant><k1="v1"></SomeTagIwant>

  DB<155> p $y
<blah1 phase="2" type="MyType" more_keys="Values" <Unwanted/>


  DB<156> $re = qr/ \btype = "([^"]+)" .+?  (?: < ( \w+TagIwant)\b | $
+ ) /x


  DB<157> print join "|", $x =~ $re
MyType|SomeTagIwant

  DB<158> print join "|", $y =~ $re
MyType|
[download]

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!}