Re: Find pieces of text in a file enclosed by `@` and replace the inside

in reply to Find pieces of text in a file enclosed by `@` and replace the inside

Step one is that you replace text between '@' delimiters. You can do that using

s/\@(.*?)\@/ ... /g;
[download]

Step two is to replace individual characters on the selected part.

Using the /e modifier you can use perl code in the substitution part, where you can use $1 as a normal variable. With a pair of "{}" delimiters on the right hand side, it can even look like normal code, as it looks like a block; you have to use similar paired delimiters on the left to make it work, for example using angle brackets "<>":

s<\@(.*?)\@>{ ... }ge;
[download]

So you might try to do the replacement using code directly in the substitution part. But, to be safe, you'd better call a sub to do the actual replacement, on the selected text. I'd change your code like this:

while(<>) {
    s/\@(.*?)\@/ subst($1) /ge;
    print;
}
sub subst {
    my $s = shift;
    my %r = (
        'a' => chr(0x430),
        'b' => chr(0x431),
        'c' => chr(0x446),
        'd' => chr(0x434),
        'e' => chr(0x435),
        'A' => chr(0x410),
        'B' => chr(0x411),
        'C' => chr(0x426)
    );
    $s =~ s/([a-eA-C])/$r{$1}/g;
    return $s;
}
[download]

Caveat: untested.

update: Tested, and bug fixed, this line was wrong:

    s/\@(.*)\@/ subst($1) /ge;
[download]

Comment on Re: Find pieces of text in a file enclosed by `@` and replace the inside Select or Download Code

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Re^2: Find pieces of text in a file enclosed by `@` and replace the inside by McA (Priest) on Mar 08, 2013 at 12:16 UTC
Hi, one question to the (very nice) solution: I'm not sure whether I'm right. Is it possible that there are perl bugs in older versions with exactly this kind of substitution pattern: `s/pattern/ func(bla) /ge;` [download] I'm just curious. Probably it was in another context. Where are the perl core hackers? Best regards McA	[reply] [d/l]
Re^3: Find pieces of text in a file enclosed by `@` and replace the inside by bart (Canon) on Mar 09, 2013 at 21:27 UTC
I'm not sure what you mean. But I know that $1 and friends are block scoped, meaning that it's safe, and has always been safe, to nest substitutions provided the inner substitution was in a block. Calling a sub is one safe way to achieve that. It also has the added advantage that you don't have to take care of having to escape any unpaired nested braces: the substitution part may look like a code block to us, but it actually isn't.	[reply]
Re^2: Find pieces of text in a file enclosed by `@` and replace the inside by kluther (Novice) on Mar 08, 2013 at 11:50 UTC
Thanks for your quick response. The code is not the solution. The second word of the first line is replaced also eventhough it is not surrounded by '@''s.	[reply]
Re^3: Find pieces of text in a file enclosed by `@` and replace the inside by bart (Canon) on Mar 08, 2013 at 11:51 UTC
Yeah, I just tested it. I forgot the question mark. Now it works.	[reply]
Re^4: Find pieces of text in a file enclosed by `@` and replace the inside by kluther (Novice) on Mar 08, 2013 at 12:02 UTC
Wonderfull, thanks!	[reply]
Re^4: Find pieces of text in a file enclosed by `@` and replace the inside by kluther (Novice) on Mar 08, 2013 at 13:43 UTC
Just one question. How do I exclude an email-address from processing?	[reply]
Re^5: Find pieces of text in a file enclosed by `@` and replace the inside by bart (Canon) on Mar 12, 2013 at 21:08 UTC
Re^6: Find pieces of text in a file enclosed by `@` and replace the inside by kluther (Novice) on Mar 29, 2013 at 05:16 UTC
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