Dear Monks

When I read perl cook book,I found the following code:

our ($rows, $cols);         #if use my ($rows,$cols), it will not work
no strict 'refs';                   # for ${$1}/g below
my $text;

($rows, $cols) = (24, 80);
$text = q(I am $rows high and $cols long);  # like single quotes!
$text =~ s/\$(\w+)/${$1}/g;
print $text;
#I am 24 high and 80 long

[download]

I am wondering why lexical variable (using my) will not work in this case.

Thank you!

Update:

Got the answer, sorry for this silly question.

symbolic reference is interpreted as a string representing the name of a global variable. So if I use symbolic reference as above, it has to refer to a global variable.

By the way, does anyone know if there will be a new version of Perl Cookbook?

Update questions:

Thank you for replying to my questions.

After playing around with this '/e' modifier with s///, I do have a question which I cannot solve now:

$AGE = 17;
$text = 'I am $AGE years old';      # note single quotes
$text =~ s/(\$\w+)/$1/eeg;           # print I am 17 years old
$text =~ s/(\$\w+)/$1 * 2/eegx;  #I tried to double the age, but faile
+d

[download]

How I can double the age in s/// format for the above code as showed by a similar but different example:

$text = "I am 17 years old";
$text =~ s/(\d+)/2 * $1/eg; #now I am 34 years old

[download]

Thank you.

In reply to why lexical variables can not be interpolated? by lightoverhead

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