[dancer-users] About Route Handlers

[Andrew Solomon]

Thanks for pointing out the error Kadir! The fix should be in the next
release:

https://github.com/PerlDancer/Dancer2/pull/878

cheers

Andrew

On Fri, Apr 3, 2015 at 10:29 PM, Kadir Beyazlı <kadirbeyazli at gmail.com>
wrote:

> 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 at 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 at 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 at 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
>>>> <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
>>>> <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 <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
>>>> <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 BeyazlıComputer Engineer*
>>>> *GSM : +90 535 821 50 00 <%2B90%20535%20821%2050%2000>*
>>>>
>>>> _______________________________________________
>>>> dancer-users mailing list
>>>> dancer-users at dancer.pm
>>>> http://lists.preshweb.co.uk/mailman/listinfo/dancer-users
>>>>
>>>>
>>> _______________________________________________
>>> dancer-users mailing list
>>> dancer-users at dancer.pm
>>> http://lists.preshweb.co.uk/mailman/listinfo/dancer-users
>>>
>>>
>>
>>
>> --
>> Andrew Solomon
>>
>> Mentor at Geekuni http://geekuni.com/
>> http://www.linkedin.com/in/asolomon
>>
>> _______________________________________________
>> dancer-users mailing list
>> dancer-users at dancer.pm
>> http://lists.preshweb.co.uk/mailman/listinfo/dancer-users
>>
>>
>
>
> --
>
> *Kadir BeyazlıComputer Engineer*
> *GSM : +90 535 821 50 00 <%2B90%20535%20821%2050%2000>*
>
> _______________________________________________
> dancer-users mailing list
> dancer-users at dancer.pm
> http://lists.preshweb.co.uk/mailman/listinfo/dancer-users
>
>


-- 
Andrew Solomon

Mentor at Geekuni http://geekuni.com/
http://www.linkedin.com/in/asolomon
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.preshweb.co.uk/pipermail/dancer-users/attachments/20150403/3f3f74cd/attachment-0001.html>