Re^2: Bizarreness in ?PATTERN? and g

No no no, you're missing my point. I realize that ?? only matches once, but shouldn't the second regex be seperate from the first regex?

/regex1/
/regex2/
[download]

Regex1 and 2 shouldn't have anything to do with each other, should they? But in my example, the two ??'s are affecting each other, but they're completely seperate!

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Re^3: Bizarreness in ?PATTERN? and g by Mr. Muskrat (Canon) on Jun 04, 2004 at 05:09 UTC
If you want them separate then remove the g modifier. `$_="a1 a2 a3"; while(?a(\d)?){ print $1; } while(?a(\d)?){ print $1; } __END__ 11` [download] Updated to add in the snippet.	[reply] [d/l]
Re^4: Bizarreness in ?PATTERN? and g by BUU (Prior) on Jun 04, 2004 at 05:16 UTC
I realize that, but why is one affecting the other?	[reply]
Re^5: Bizarreness in ?PATTERN? and g by Mr. Muskrat (Canon) on Jun 04, 2004 at 05:24 UTC
That is how the g modifier works in scalar context. The match doesn't fail in the first or second attempt nor do you use reset so pos() is not reset and the next pattern will match where the last one left off. Read the entire section of perlop that deals with m/PATTERN/cgimosx & /PATTERN/cgimosx because it explains it very clearly.	[reply]
Re^5: Bizarreness in ?PATTERN? and g by halley (Prior) on Jun 04, 2004 at 13:17 UTC
The intent of the interaction between `/g` and `pos()` is to allow you to build parsers that "consume" a string. You read the first part, and if that matches, you read the second part, and if that fails, you try an alternative for the second part, and so on. Check out the Mastering Regular Expressions book for some ideas on how to keep this in mind, and take advantage of it for parsing tasks. -- `[ e d @ h a l l e y . c c ]`	[reply] [d/l] [select]