Escape Quote-Like Operators

MentalAbsence has asked for the wisdom of the Perl Monks concerning the following question:

Is there a way to cause letters that begin quote-like operators such as m, s, qq, qr, and friends to be treated as barewords as opposed to the beginning of a quoted or regular expression string? If you look at the following nonsensical example:

$_ = '12';
s/(\d+)/($1 > 10)?m:n/e;
[download]

The intent is to replace the number in $_ with either 'm' or 'n', but Perl complains:

"Search pattern not terminated..."

because it thinks that 'm:' is the start of a regular expression match operator. Of course, I can quote the 'm' and everything works fine, but unfortunately this is for golf and I'd like to be able to leave off the quotes if possible to save characters. Is there a way to escape the 'm' or cause it not to be treated as an operator at a cost of fewer than the two characters it takes to quote it? Thanks for your thoughts!

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Re: Escape Quote-Like Operators by BrowserUk (Patriarch) on Sep 11, 2013 at 17:10 UTC
With /e, the replacement is interpreted as code, so do what you'd normally do and quote the letters: `s/(\d+)/($1 > 10)?'m':'n'/e;` [download] With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply] [d/l]
Re: Escape Quote-Like Operators by SuicideJunkie (Vicar) on Sep 11, 2013 at 18:04 UTC
You could have `$m` there and 'escape' with one character if you were able to set some one-letter variable to 'm'; earlier. Something like `s/(\d+)/chr 110-($_>10)/e;` could work but its a bit longer. `s/(\d+)/qw(n m)[$_>10]/e;` is another path. I'm no golfer, but maybe those might give you some ideas.	[reply] [d/l] [select]
Re: Escape Quote-Like Operators by tobyink (Canon) on Sep 11, 2013 at 17:50 UTC
Could you use capital letters? `use Moops; class Cow :rw { has name => (default => 'Ermintrude') }; say Cow->new->name`	[reply]
Re: Escape Quote-Like Operators by kennethk (Abbot) on Sep 11, 2013 at 18:37 UTC
What's your actual use case? You can save a bunch of characters by not branching (in your nonsensical example): `$_ = '12'; s/\d/n/g;s/n+/m/;` [download] Update: Or, if you pay 3 more (still saving 2 from your 'ideal') you can get identical algorithmic behavior: `$_ = '12'; s/\d\d+/m/\|\|s/\d/n/;` [download] LTS FTW Thanks to Anonymous Monk, realized my brain misread the comparator. However, the real use case is still relevant. As penance, optimization of the nonsensical example: `$_ = '12'; s/\d+/$&>10?'m':n/e;` [download] #11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.	[reply] [d/l] [select]
Re^2: Escape Quote-Like Operators by Anonymous Monk on Sep 11, 2013 at 20:24 UTC
Wouldn't that replace '10' with 'm' by mistake?	[reply]
Re^3: Escape Quote-Like Operators by kennethk (Abbot) on Sep 11, 2013 at 21:08 UTC
It would; parse fail. #11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.	[reply]
Re: Escape Quote-Like Operators (fat comma) by tye (Sage) on Sep 12, 2013 at 01:37 UTC
`# s/(\d+)/($1 > 10)?'m':n/e; s/\d+/(m=>n)[$&<11]/e;` [download] - tye	[reply] [d/l]
Re^2: Escape Quote-Like Operators (fat comma) by LanX (Saint) on Sep 12, 2013 at 10:15 UTC
nice, but only $& and not fat comma leads to a reduction ... :) `DB<108> $_=12;s/\d+/(m=>n)[$&<11]/e;$_ => "m" DB<109> $_=12;s/\d+/($&>10)?'m':n/e;$_ => "m"` [download]	[reply] [d/l]
Re: Escape Quote-Like Operators by Not_a_Number (Prior) on Sep 11, 2013 at 19:52 UTC
No idea what your context is, but just to replace a number higher than 10 by 'm', lower or equal by 'n', what's wrong with this?: `$_=$_>10?'m':n;`	[reply] [d/l]