Perl6 negating user defined caracter class
I'm trying to ignore all the lines that have quotes in it, somehow it looks like:
> my $y='\"\""';
\"\""
> so $y ~~ m/<-[\"]>/
True # $y has a " mark, so I want it to be False
> $y ~~ m/<-[\"]>/
｢\｣
> $y ~~ m:g/<-[\"]>/
(｢\｣ ｢\｣)
> $y ~~ m:g/<-["]>/
(｢\｣ ｢\｣)
$y ~~ m/<-[\\]>/
｢"｣
> $y ~~ m/<-[\\\"]>/
False
Is <- [\ "]> the same as <- ["]>?
> say '"in quotes"' ~~ / '"' <-[ " ]> * '"'/;
｢"in quotes"｣
> say 'no "foo" quotes' ~~ / <-[ " ]> + /;
｢no ｣
> say 'no "foo" quotes' ~~ / <-[ \" ]> + /;
｢no ｣
In the perl6 documentation example https://docs.perl6.org/language/regexes#Wildcards_and_character_classes, the author didn't need to hide the quote; however, I need to escape for it to work, <- [\\ "]>, that is, escape \ and escape". What have I misunderstood?
Thank!
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You don't need to escape characters inside a character class specification other than the backslash itself: so the specification is the <-[\"]>
same as <-["]>
. And the indication <-[\\"]>
indicates all characters except \
and "
.
However, there might be an easier way for you: if you are looking for only one (set) of character (s) per string, there contains
:
my $y = "foo bar baz";
say $y.contains("oo"); # True
This bypasses all expensive regex / grammar machines using one simple low level string match.
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