[dancer-users] About Route Handlers

[Kadir Beyazlı]

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
>>>
>>>
>> _______________________________________________
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>>
>
>
> --
> 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*
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