dereferencing anonymous arrays in Perl

coolman0stress · 10-26-2003, 07:24 PM

Hey guys,

In Perl you can create anonymous arrays, i'm having trouble understanding something:

Code:

@array= (1,2,3);
$ref= \@array; # create reference
print @$ref; # standard dereference

# can create a reference to an anonymous array as follows:

$ref= [@array]; 
print @$ref; # dereference

# So why then won't this work:

print @[@array]; # why won't this work?

# Why do you have to do this instead?

print @{[@array]};

Can someone explain why @{} is required?

Thanks in advance...

cools

infamous41md · 10-26-2003, 08:54 PM

well i know the simple explanation is b/c of operator precedence. you want to apply the
'@' operator to the entire expression [@array]. using { } creates a separate block of code
for that to run in. then the expression is dereferenced.

coolman0stress · 10-26-2003, 09:08 PM

Humm.. that does make sense, so why then can't you seperate the @ from the rest using ():

print @([@array]);

Or do the paranthesis prevent returning of anonymous array reference to use with @?

infamous41md · 10-27-2003, 12:24 AM

honestly i dont know. im no perl wizard. the book i was looking thru sux, it didn't explain it. i just remember that was always the syntax used, and i remember finding it hard to understand as well. i dont really program in perl much, i'd be scared to show anyone my perl scripts as they are prolly hideous! C for me, sorry i can't help u anymore, maybe some perl monkeys can

coolman0stress · 10-27-2003, 05:36 PM

Well thanks for your help so far.

I'm revisiting Perl in general. I took a course last semester and though i was very excited at first, in the end i was some what dissappointed. So now i'm digging a bit deeper and see what i can find.

infamous41md · 10-27-2003, 10:11 PM

heh that's quite funny. i learned perl this summer just b/c i wanted to see how other languages are(im a c* guy). at first it was cool with all the shortcuts and whatnot, but then when it came to actually create a serious program...i just laughed. i donno, i dont take perl serious. i just use it to write utilities and page long at most scripts. i didn't really find CGI programming fun at all, it's too visual for my likes. im more into nuts and bolts then pretty colors i guess. but my friends all tell me that im missing out on the good stuff in perl... maybe one day i'll have to buy the o'reilly books and really learn it

coolman0stress · 10-27-2003, 10:17 PM

I definately share your views on Perl. I got the exact same feelilng at first: "WOW look how fast i can write this and that". Once it came to writing anything longer than 200 lines, damn does it get annoying and dissorganized fast.

After taking a break from it i got offered a "quick" job making a website. So now i'm taking the time to review but also go deeper than before.

So now i'm checking out gui programming with Tk. So far (being Perl), it's fairly easy and straightforward (i'm comparing to the stuff i've done so far in Java swing). We'll see how it turns out once i try to write larger apps.