Re: Recognizing all-caps line

Try either of the following:

$line =~ m/^[[:upper:]]+$/ # or $line =~ m/^\p{IsUpper}+$/

the [: ... :] is no character class, although it looks like one.
To make it (part of) a character class, you need another set of brackets around it.

don't go for m/^[A-Z]+$/ for ~~world peace~~ international reasons ;-)
See perldoc perlre too.

Update: You might find the double negation more convenient:

$line !~ m/[[:^upper:]]/ # or $line !~ m/\P{IsUpper}/

(think: do not match a line that contains anything that's not an uppercase letter)

Edit: corrected a number of mistakes.
Thanks especially to davido(++) for pointing out the ones I didn't find myself. Strange enough, while the necessity of the double brackets is not in doubt, I don't get any warnings when omitting them (perl5.8.3, Linux), the code just never tests true.
Another Edit: I guess that's because it looks like a character class to Perl. So why did it throw errors when davido tried it?
Another edit (and moved this discussion to the bottom of the node) -
I tried m/[:^upper:]/; which bypasses warnings.
Congratulations to us, we found a bug.

Cheers, Sören

Comment on Re: Recognizing all-caps line

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Re^2: Recognizing all-caps line by davido (Cardinal) on Oct 27, 2004 at 21:46 UTC
Happy-the-monk has it right, that this is better done by posix character classes rather than enumerated-alphabet character classes. The problem with a `[A-Z]` character class is that it may exclude some perfectly legitimate upper-case characters in non-ASCII character encodings. The solution is POSIX character classes that do understand what constitutes an upper-case character in non-ASCII character encoding. There are a couple errors in Happy's response though. First, `[:lower:]` should be `[:upper:]` in order to match upper case characters, as the OP's question asked. Update: Looks like that first problem was fixed in an update. Second, the POSIX character class identifier has to be placed inside of a character class, leading to what might seem like a little bit of a wierd syntax, but is nevertheless necessary. Hense, the following: `m/^[:upper:]+$/` ... will fail to match, and will generate a warning if `use warnings` is active (Updated), whereas ... `m/^[[:upper:]]$/` will do what you want. Dave	[reply] [d/l] [select]

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Re^2: Recognizing all-caps line
by davido (Cardinal) on Oct 27, 2004 at 21:46 UTC

Happy-the-monk has it right, that this is better done by posix character classes rather than enumerated-alphabet character classes. The problem with a [A-Z] character class is that it may exclude some perfectly legitimate upper-case characters in non-ASCII character encodings.

The solution is POSIX character classes that do understand what constitutes an upper-case character in non-ASCII character encoding.

There are a couple errors in Happy's response though. First, [:lower:] should be [:upper:] in order to match upper case characters, as the OP's question asked. Update: Looks like that first problem was fixed in an update.

Second, the POSIX character class identifier has to be placed inside of a character class, leading to what might seem like a little bit of a wierd syntax, but is nevertheless necessary. Hense, the following:

m/^[:upper:]+$/

... will fail to match, and will generate a warning if use warnings is active (Updated), whereas ...

m/^[[:upper:]]$/

will do what you want.

Dave

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