Re^4: Return string that starts and ends with specific characters

Yes regexes are optimized, if there is a leading or trailing string it's taken into consideration ( I'm to lazy to proof it with re deparse)

but this looks like a fortunate bug, because ^ is a metacharacter in some positions, it's treated differently.

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)

Je suis Charlie!}

Comment on Re^4: Return string that starts and ends with specific characters

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Re^5: Return string that starts and ends with specific characters by LanX (Saint) on Aug 19, 2016 at 21:56 UTC
> but this looks like a fortunate bug, because ^ is a metacharacter in some positions, it's treated differently. I finally understood that it's not a bug, because ^ is always a metacharacter, in order to match a literal `^` one needs to escape it And "Match the beginning of the line" will always fail unless modifiers like `/m` are used `DB<1> p "a^b" =~ /a^b/ DB<2> p "a^b" =~ /a\^b/ 1 DB<3> p "\nb" =~ /^b/m 1` [download] Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :) Je suis Charlie!}	[reply] [d/l] [select]

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> but this looks like a fortunate bug, because ^ is a metacharacter in some positions, it's treated differently.

I finally understood that it's not a bug, because ^ is always a metacharacter, in order to match a literal ^ one needs to escape it

And "Match the beginning of the line" will always fail unless modifiers like /m are used

  DB<1> p "a^b" =~ /a^b/


  DB<2> p "a^b" =~ /a\^b/
1

  DB<3> p "\nb" =~ /^b/m
1
[download]

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)

Je suis Charlie!}