comment on

Yes, interpolation means double quoted string, regex metacharacters are still regex metacharacters m/.$/ and m'.$' match the same string

$ perl -Mre=debug -e " $_ = 1234; m/.$/ "
Compiling REx ".$"
Final program:
   1: REG_ANY (2)
   2: EOL (3)
   3: END (0)
anchored ""$ at 1 minlen 1
Matching REx ".$" against "1234"
   3 <123> <4>               |  1:REG_ANY(2)
   4 <1234> <>               |  2:EOL(3)
   4 <1234> <>               |  3:END(0)
Match successful!
Freeing REx: ".$"

$ perl -Mre=debug -e " $_ = 1234; m'.$' "
Compiling REx ".$"
Final program:
   1: REG_ANY (2)
   2: EOL (3)
   3: END (0)
anchored ""$ at 1 minlen 1
Matching REx ".$" against "1234"
   3 <123> <4>               |  1:REG_ANY(2)
   4 <1234> <>               |  2:EOL(3)
   4 <1234> <>               |  3:END(0)
Match successful!
Freeing REx: ".$"
[download]

variables interpolate in double quoted strings but metachars are still metachars

$ perl -Mre=debug -e " $x = q{\d}; $f = 1234; $f =~ q{$x} "
Compiling REx "$x"
Final program:
   1: EOL (2)
   2: EXACT <x> (4)
   4: END (0)
anchored "x" at 0 (checking anchored) minlen 1
Guessing start of match in sv for REx "$x" against "1234"
Did not find anchored substr "x"...
Match rejected by optimizer
Freeing REx: "$x"

$ perl -Mre=debug -e " $x = q{\d}; $f = 1234; $f =~ qq{$x} "
Compiling REx "\d"
Final program:
   1: DIGIT (2)
   2: END (0)
stclass DIGIT minlen 1
Matching REx "\d" against "1234"
Matching stclass DIGIT against "1234" (4 bytes)
   0 <> <1234>               |  1:DIGIT(2)
   1 <1> <234>               |  2:END(0)
Match successful!
Freeing REx: "\d"

$ perl -Mre=debug -e " $x = q{\d}; $f = 1234; $f =~ qq{\$x} "
Compiling REx "$x"
Final program:
   1: EOL (2)
   2: EXACT <x> (4)
   4: END (0)
anchored "x" at 0 (checking anchored) minlen 1
Guessing start of match in sv for REx "$x" against "1234"
Did not find anchored substr "x"...
Match rejected by optimizer
Freeing REx: "$x"

$ perl -Mre=debug -e " $x = q{\d}; $f = 1234; $f =~ q{\$x} "
Compiling REx "\$x"
Final program:
   1: EXACT <$x> (3)
   3: END (0)
anchored "$x" at 0 (checking anchored isall) minlen 2
Guessing start of match in sv for REx "\$x" against "1234"
Did not find anchored substr "$x"...
Match rejected by optimizer
Freeing REx: "\$x"
[download]

In reply to Re^5: Misreading m// documentation (BUG?) by Anonymous Monk
in thread Misreading m// documentation by QM

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		`&`
	<		`<`
	>		`>`
	[		`[`
	]		`]`

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.