Hi Perrett && Andrew,

Thanks for your reply,

@Perrett,

In perl, the value of the last statement executed in a code block is it's return value

I surprised very much.

At following code, I thought it would print '3', but it writes '4' which means that you are right.

my $var = '3';
$var = &test;

print $var; # prints 3 not 4 although there is no return at sub test
 
sub test {
 "4";
}

Althouh I worked with Perl CGI for 7 years I realized now, this is bad for me! Until today, I always wrote 'return 4' for following example thinking that Perl behaves lile C code

@Andrew

You are right too. But I did not realize that there is '.' instead of '?'

But I think most people reading manual may not realize this because code is from manual so if it was written by mistake, I think it should be corrected

get '/hello/:name?' => sub {
    "Hello there, " . defined param('name')
                    ? param('name')
                    : "whoever you are!";
};

On Fri, Apr 3, 2015 at 9:11 PM, Andrew Solomon <andrew@geekuni.com> wrote:

Hi Kadir

For test3 I think you were expecting the behaviour of this code

get '/test3/:name' => sub {

    "Hello there, " .

    (defined param('name') ? param('name') : "whoever you are!");

};

but you were getting the behaviour of this code

get '/test3/:name' => sub {

    ("Hello there, " .  defined param('name')) ?

      param('name') : "whoever you are!";

};

The reason for this is that '.' has higher operator precedence than '?:'

http://perldoc.perl.org/perlop.html#Operator-Precedence-and-Associativity

Hope that helps!

Andrew

On Fri, Apr 3, 2015 at 6:59 PM, D Perrett <perrettdl@googlemail.com> wrote:

In perl, the value of the last statement executed in a code block is it's return value, an explicit return is only needed if you want to exit the chose block earlier than the last statement. Not sure why your third example isn't working for you. Have you restarted your dancer server since you edited the code?

Daniel

On 3 Apr 2015 18:30, "Kadir Beyazlı" <kadirbeyazli@gmail.com> wrote:

Hi All,

I am novice at Dancer, I am sure my question is very easy for you but I decided to ask because I failed at the beginning of my study.

I started reading following manual :

https://metacpan.org/pod/Dancer2::Manual

I installed Dancer2, placked up it and opened web page from localhost.

Everything is OK until here.

There is following info at manual:

The code block given to the route handler has to return a string which will be used as the content to render to the client.

It is clear for following example

get '/test1/:name' => sub {
    return "Hi there " . params->{name};
};

because it returns a string and when I write http://localhost:5000/test1/kadir to browser I see  Hi there kadir which is the string I expect to see

But next example is as follow:

get '/test2/:name' => sub {
    "Hey ".param('name').", welcome here!";
};

It does not return anything. Because there is no return keyword.

Despite this I see   Hi there kadir  when I write http://localhost:5000/test2/kadir

But above red background colored sentence says that it must return a value?

Next example is stranger:

get '/test3/:name' => sub {
    "Hello there, " . defined param('name')
                    ? param('name')
                    : "whoever you are!";
};

Again there is no return keyword. When I write http://localhost:5000/test3/kadir I see only kadir. But at test2 example, I saw all words despite there is no return keyword. So what is rule?

--

Kadir Beyazlı
Computer Engineer

GSM : +90 535 821 50 00

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--

Andrew Solomon

Mentor@Geekuni http://geekuni.com/

http://www.linkedin.com/in/asolomon

_______________________________________________
dancer-users mailing list
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--

Kadir Beyazlı
Computer Engineer

GSM : +90 535 821 50 00

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