Design by Contract â Perl

Âÿ÷åñëàâ Òèõàíîâñêèé (vti)

2012-12-22

showmetheco.de

ÎÎÏ

Moose, Moos, Moo, Mo, M?

Èíòåðôåéñû è íàñëåäîâàíèå îò àáñòðàêòíîãîêëàññà

package Abs t r a c tRende r e r ;

sub new { . . . }

sub r e nd e r { die ' Implement me ! ' }

package TT;use base ' Ab s t r a c tRende r e r ' ;sub r e nd e r {

my $ s e l f = s h i f t ;my ( $template , $ l ayou t , %va r s ) = @_;

return \ $ r ende r ed ;}

package Caml ;use base ' Ab s t r a c tRende r e r ' ;sub r e nd e r {

my $ s e l f = s h i f t ;my ( $template , %va r s ) = @_;

return $ r ende r ed ;}

Design by Contract

I Ïðîâåðêà âõîäíûõ è âûõîäíûõ óñëîâèé

I Ñëåäîâàíèå ïðèíöèïó ïîäñòàíîâêè Ëèñêîâ (Lâ SOLID) ïðè íàñëåäîâàíèè

I Äîêóìåíòèðîâàíèå èíòåðôåéñà

I Ïðîâåðêà âõîäíûõ è âûõîäíûõ óñëîâèé

I Ñëåäîâàíèå ïðèíöèïó ïîäñòàíîâêè Ëèñêîâ (Lâ SOLID) ïðè íàñëåäîâàíèè

I Äîêóìåíòèðîâàíèå èíòåðôåéñà

I Ïðîâåðêà âõîäíûõ è âûõîäíûõ óñëîâèé

I Ñëåäîâàíèå ïðèíöèïó ïîäñòàíîâêè Ëèñêîâ (Lâ SOLID) ïðè íàñëåäîâàíèè

I Äîêóìåíòèðîâàíèå èíòåðôåéñà

package Abs t r a c tRende r e r ;sub new { . . . }

# Requ i r e s (STRING , %HASH_OF_ANY_VALUES)# Ensu re s (STRING)# Throws ( Excep t i on : : TemplateNotFound )sub r e nd e r {

my $ s e l f = s h i f t ;my ( $template , %va r s ) = @_;

. . .

return $ r ende r ed ;}

package TT;use base ' Ab s t r a c tRende r e r ' ;sub r e nd e r { . . . }

package Caml ;use base ' Ab s t r a c tRende r e r ' ;sub r e nd e r { . . . }

I Íå äîëæíî ñíèæàòü ÷èòàåìîñòü

I Íå òðåáóåò áîëüøèõ âû÷èñëèòåëüíûõðåñóðñîâ

I Îòêëþ÷àåìî

I Íàñëåäóåìî

I Çàïðåùàåò ìåíÿòü êîíòðàêò â äî÷åðíèõêëàññàõ

I Ïîíÿòíûå îøèáêè

I Êàê ìîæíî ìåíüøå ìàãèè*

I Ïîõîæå íà Perl*

I Íå äîëæíî ñíèæàòü ÷èòàåìîñòü

I Íå òðåáóåò áîëüøèõ âû÷èñëèòåëüíûõðåñóðñîâ

I Îòêëþ÷àåìî

I Íàñëåäóåìî

I Çàïðåùàåò ìåíÿòü êîíòðàêò â äî÷åðíèõêëàññàõ

I Ïîíÿòíûå îøèáêè

I Êàê ìîæíî ìåíüøå ìàãèè*

I Ïîõîæå íà Perl*

I Íå äîëæíî ñíèæàòü ÷èòàåìîñòü

I Íå òðåáóåò áîëüøèõ âû÷èñëèòåëüíûõðåñóðñîâ

I Îòêëþ÷àåìî

I Íàñëåäóåìî

I Çàïðåùàåò ìåíÿòü êîíòðàêò â äî÷åðíèõêëàññàõ

I Ïîíÿòíûå îøèáêè

I Êàê ìîæíî ìåíüøå ìàãèè*

I Ïîõîæå íà Perl*

I Íå äîëæíî ñíèæàòü ÷èòàåìîñòü

I Íå òðåáóåò áîëüøèõ âû÷èñëèòåëüíûõðåñóðñîâ

I Îòêëþ÷àåìî

I Íàñëåäóåìî

I Çàïðåùàåò ìåíÿòü êîíòðàêò â äî÷åðíèõêëàññàõ

I Ïîíÿòíûå îøèáêè

I Êàê ìîæíî ìåíüøå ìàãèè*

I Ïîõîæå íà Perl*

I Íå äîëæíî ñíèæàòü ÷èòàåìîñòü

I Íå òðåáóåò áîëüøèõ âû÷èñëèòåëüíûõðåñóðñîâ

I Îòêëþ÷àåìî

I Íàñëåäóåìî

I Çàïðåùàåò ìåíÿòü êîíòðàêò â äî÷åðíèõêëàññàõ

I Ïîíÿòíûå îøèáêè

I Êàê ìîæíî ìåíüøå ìàãèè*

I Ïîõîæå íà Perl*

I Íå äîëæíî ñíèæàòü ÷èòàåìîñòü

I Íå òðåáóåò áîëüøèõ âû÷èñëèòåëüíûõðåñóðñîâ

I Îòêëþ÷àåìî

I Íàñëåäóåìî

I Çàïðåùàåò ìåíÿòü êîíòðàêò â äî÷åðíèõêëàññàõ

I Ïîíÿòíûå îøèáêè

I Êàê ìîæíî ìåíüøå ìàãèè*

I Ïîõîæå íà Perl*

I Íå äîëæíî ñíèæàòü ÷èòàåìîñòü

I Íå òðåáóåò áîëüøèõ âû÷èñëèòåëüíûõðåñóðñîâ

I Îòêëþ÷àåìî

I Íàñëåäóåìî

I Çàïðåùàåò ìåíÿòü êîíòðàêò â äî÷åðíèõêëàññàõ

I Ïîíÿòíûå îøèáêè

I Êàê ìîæíî ìåíüøå ìàãèè*

I Ïîõîæå íà Perl*

I Íå äîëæíî ñíèæàòü ÷èòàåìîñòü

I Íå òðåáóåò áîëüøèõ âû÷èñëèòåëüíûõðåñóðñîâ

I Îòêëþ÷àåìî

I Íàñëåäóåìî

I Çàïðåùàåò ìåíÿòü êîíòðàêò â äî÷åðíèõêëàññàõ

I Ïîíÿòíûå îøèáêè

I Êàê ìîæíî ìåíüøå ìàãèè*

I Ïîõîæå íà Perl*

Class::Contract

use C l a s s : : Cont rac t ;

c o n t r a c t {i n h e r i t s ' Ba seC l a s s ' ;

c t o r ' new ' ;

method 'methodname ' ;p r e { . . . } ;

f a i lm s g ' E r r o r message ' ;

po s t { . . . } ;f a i lm s g ' E r r o r message ' ;

imp l { . . . } ;} ;

Sub::Contract

use Sub : : Cont rac t qw( c o n t r a c t ) ;

c o n t r a c t ( ' s u r f a c e ' )−>in (\& i s_ i n t e g e r , \& i s_ i n t e g e r )−>out (\& i s_ i n t e g e r )−>enab l e ;

sub s u r f a c e {# no need to v a l i d a t e arguments anymore !# j u s t implement the l o g i c :return $_ [ 0 ] ∗ $_ [ 1 ] ;

}

Sub::Assert

a s s e r tp r e => {' paramete r l a r g e r than one ' => '$PARAM[ 0 ] >= 1 ' ,

} ,po s t => '$VOID or $RETURN <= $PARAM[ 0 ] ' ,sub => ' s qu a r e r o o t ' ,c on t e x t => ' novo id ' ,a c t i o n => ' ca rp ' ;

Carp::Datum

use Carp : : Datum ;

sub r o u t i n e {DFEATURE my $f_ , " o p t i o n a l message " ;my ( $a , $b ) = @_;DREQUIRE $a > $b , "a > b" ;$a += 1 ; $b += 1 ;DASSERT $a > $b , " o r d e r i n g a > b p r e s e r v e d " ;my $ r e s u l t = $b − $a ;DENSURE $ r e s u l t < 0 ;return DVAL $ r e s u l t ;

}

MooseX::Contract

c o n t r a c t ' add '=> acc ep t s [ . . . t ype . . . ]=> r e t u r n s vo id ,w i th_context (

p re => sub {. . .

} ,po s t => a s s e r t {

. . .}

) ;sub add {

my $ s e l f = s h i f t ;my $ i n c r = s h i f t ;$ s e l f −>{va l u e } += $ i n c r ;return ;

}

Attribute::Contract

package Abs t r a c tRende r e r ;use A t t r i b u t e : : Con t r ac t ;

sub new { . . . }

sub r e nd e r: Con t r a c tRequ i r e s (VALUE( S t r ) , %ANY): Con t r a c tEn su r e s (VALUE( S t r ) ): ContractThrows ( Excep t i on : : TemplateNotFound ) {

}

DbC è TDD

DbC è Defensive programming

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