Things you can't do in Ruby

Transcript

1. Things you can't do in Ruby / Piotr Nielacny @piterniel
2. Multi-inheritance c l a s s M y C l a s s < F i r s t C l a s s , S e c C l a s s e n d # # # S y n t a x E r r o r : ( i r b ) : 1 : s y n t a x e r r o r , u n e x p e c t e d ' , ' , e x p e c t i n g # # # ' ; ' o r ' \ n ' # # # c l a s s M y C l a s s < F i r s t C l a s s , S e c C l a s s
3. Class mixin c l a s s M y C l a s s i n c l u d e A r r a y e n d # # # T y p e E r r o r : w r o n g a r g u m e n t t y p e C l a s s ( e x p e c t e d M o d u l e )
4. Object unfreeze a = A r r a y . n e w # = > [ ] a < < " o b j e c t " # = > [ " o b j e c t " ] a . f r e e z e a . f r o z e n ? # = > t r u e a < < " o b j e c t 2 " # = > R u n t i m e E r r o r : c a n t m o d i f y f r o z e n A r r a y a . u n f r e e z e # # # N o M e t h o d E r r o r : u n d e f i n e d m e t h o d ` u n f r e e z e ' f o r [ " o b j e c t " ] : A r r a y
5. Change object class o = O b j e c t . n e w o . c l a s s # = > O b j e c t o . c l a s s = A r r a y # # # N o M e t h o d E r r o r : u n d e f i n e d m e t h o d ` c l a s s = ' f o r # `
6. And bonus syntax
7. Default argument (~coffescript) Should be equal to c l a s s D e f a u l t d e f i n i t i a l i z e ( @ n a m e ) ; e n d e n d # S y n t a x E r r o r : f o r m a l a r g u m e n t c a n n o t b e a n i n s t a n c e v a r i a b l e c l a s s D e f a u l t d e f i n i t i a l i z e ( n a m e = n i l ) @ n a m e = n a m e e n d e n d
8. Normally I should end the presentation
9. What if...
10. Clone MRI repository g i t c l o n e g i t : / / g i t h u b . c o m / r u b y / r u b y . g i t
11. Fine file i n c l u d e / r u b y / r u b y . h
12. You probably think I'll write an extension in C Hahahahahaha... no
13. In ruby.h file you can find R U B Y _ Q f a l s e = 0 , R U B Y _ Q t r u e = 2 , R U B Y _ Q n i l = 4 , R U B Y _ Q u n d e f = 6 , R U B Y _ T _ N O N E = 0 x 0 0 , R U B Y _ T _ O B J E C T = 0 x 0 1 , R U B Y _ T _ C L A S S = 0 x 0 2 , R U B Y _ T _ M O D U L E = 0 x 0 3 , R U B Y _ T _ F L O A T = 0 x 0 4 , R U B Y _ T _ S T R I N G = 0 x 0 5 , R U B Y _ T _ R E G E X P = 0 x 0 6 , R U B Y _ T _ A R R A Y = 0 x 0 7 , R U B Y _ T _ H A S H = 0 x 0 8 , R U B Y _ T _ S T R U C T = 0 x 0 9 , R U B Y _ T _ B I G N U M = 0 x 0 a , R U B Y _ T _ F I L E = 0 x 0 b ,
14. Move this to normal ruby module R U B Y _ Q f a l s e = 0 , R U B Y _ Q t r u e = 2 , R U B Y _ Q n i l = 4 , R U B Y _ Q u n d e f = 6 , R U B Y _ T _ N O N E = 0 x 0 0 , R U B Y _ T _ O B J E C T = 0 x 0 1 , R U B Y _ T _ C L A S S = 0 x 0 2 , R U B Y _ T _ M O D U L E = 0 x 0 3 , R U B Y _ T _ F L O A T = 0 x 0 4 , R U B Y _ T _ S T R I N G = 0 x 0 5 , R U B Y _ T _ R E G E X P = 0 x 0 6 , R U B Y _ T _ A R R A Y = 0 x 0 7 , R U B Y _ T _ H A S H = 0 x 0 8 , R U B Y _ T _ S T R U C T = 0 x 0 9 , R U B Y _ T _ B I G N U M = 0 x 0 a , R U B Y _ T _ F I L E = 0 x 0 b , m o d u l e R u b y I n t e r n a l Q f a l s e = 0 Q t r u e = 2 Q n i l = 4 Q u n d e f = 6 T _ N O N E = 0 x 0 0 T _ O B J E C T = 0 x 0 1 T _ C L A S S = 0 x 0 2 T _ M O D U L E = 0 x 0 3 T _ F L O A T = 0 x 0 4 T _ S T R I N G = 0 x 0 5 T _ R E G E X P = 0 x 0 6 T _ A R R A Y = 0 x 0 7 T _ H A S H = 0 x 0 8 T _ S T R U C T = 0 x 0 9 T _ B I G N U M = 0 x 0 a T _ F I L E = 0 x 0 b e n d
15. Find in ruby.h aliases for VALUE and ID t y p e d e f u n s i g n e d l o n g V A L U E ; t y p e d e f u n s i g n e d l o n g I D ;
16. And once again move to normal ruby module t y p e d e f u n s i g n e d l o n g V A L U E ; t y p e d e f u n s i g n e d l o n g I D ; m o d u l e R u b y I n t e r n a l # a l i a s ? ! e n d
17. We need to use DL (Dynamic Linker?) A bridge to the dlopen() or dynamic library linker function. r e q u i r e ' d l ' r e q u i r e ' d l / i m p o r t ' m o d u l e L i b S u m e x t e n d D L : : I m p o r t e r d l l o a d ' . / l i b s u m . s o ' e x t e r n ' d o u b l e s u m ( d o u b l e * , i n t ) ' e x t e r n ' d o u b l e s p l i t ( d o u b l e ) ' e n d
18. And once again move to normal ruby module t y p e d e f u n s i g n e d l o n g V A L U E ; t y p e d e f u n s i g n e d l o n g I D ; r e q u i r e ' d l ' r e q u i r e ' d l / i m p o r t ' m o d u l e R u b y I n t e r n a l e x t e n d D L : : I m p o r t e r t y p e a l i a s " V A L U E " , " u n s i g n e d l o n g " t y p e a l i a s " I D " , " u n s i g n e d l o n g " e n d
19. Next, structures s t r u c t R B a s i c { V A L U E f l a g s ; V A L U E k l a s s ; } ;
20. And import s t r u c t R B a s i c { V A L U E f l a g s ; V A L U E k l a s s ; } ; m o d u l e R u b y I n t e r n a l s B a s i c = [ " V A L U E f l a g s " , " V A L U E k l a s s " ] R B a s i c = s t r u c t ( B a s i c ) e n d
21. And import s t r u c t R O b j e c t { s t r u c t R B a s i c b a s i c ; u n i o n { s t r u c t { l o n g n u m i v ; V A L U E * i v p t r ; s t r u c t s t _ t a b l e * i v _ i n d e x _ t b l ; } h e a p ; V A L U E a r y [ R O B J E C T _ E M B E D _ L E N _ M A X ] ; } a s ; } ; m o d u l e R u b y I n t e r n a l o b j e c t _ s t r u c t = [ ' l o n g n u m i v ' , ' V A L U E * i v p t r ' , ' s t _ t a b l e * i v _ i n d e x _ t b l ' , ' V A L U E a r a [ 3 ] ' ] R O b j e c t = s t r u c t ( B a s i c + o b j e c t _ s t r u c t ) e n d
22. And long long and boring import ;-)
23. We have constants, type alias and structures How can we refer to them?
24. Internal pointer of ruby object d e f i n t e r n a l _ p t r ( * a r g s ) p o s = s e l f . o b j e c t _ i d * 2 D L : : C P t r . n e w ( p o s , * a r g s ) e n d
25. To internals! c l a s s O b j e c t d e f i n t e r n a l _ p t r ( * a r g s ) p o s = s e l f . o b j e c t _ i d * 2 D L : : C P t r . n e w ( p o s , * a r g s ) e n d d e f i n t e r n a l k l a s s = i n t e r n a l _ c l a s s # = > R u b y I n t e r n a l : : R O b j e c t r = k l a s s . n e w ( i n t e r n a l _ p t r ) # = > R u b y I n t e r n a l : : R O b j e c t : 0 x 0 0 0 0 0 r e n d e n d
26. Let's do what we can not do
27. Multi-inheritance d e f t o _ m o d u l e r e s u l t = s e l f . c l o n e o = R u b y I n t e r n a l : : R O b j e c t . n e w ( r e s u l t . i n t e r n a l _ p t r ) o . f l a g s & = ~ R u b y I n t e r n a l : : F L _ S I N G L E T O N o . f l a g s & = ~ R u b y I n t e r n a l : : T _ M A S K o . f l a g s | = R u b y I n t e r n a l : : T _ M O D U L E o . k l a s s = M o d u l e . i n t e r n a l _ p t r . t o _ i r e t u r n r e s u l t e n d
28. Unfreeze object d e f u n f r e e z e s e l f . i n t e r n a l . f l a g s & = ~ R u b y I n t e r n a l : : F L _ F R E E Z E r e t u r n s e l f e n d
29. Change object class d e f c l a s s = ( o t h e r ) s e l f . i n t e r n a l . k l a s s = o t h e r . i n t e r n a l _ p t r . t o _ i e n d
30. DEMO
31. Default argument c l a s s D e f a u l t d e f i n i t i a l i z e ( @ n a m e ) ; e n d e n d
32. formal argument cannot be an instance variable
33. formal argument cannot be an instance variable
34. formal argument cannot be an instance variable
35. formal argument cannot be an instance variable
36. GREP!
37. | t I V A R { y y _ e r r o r ( " f o r m a l a r g u m e n t c a n n o t b e a n i n s t a n c e v a r i a b l e " ) ; $ $ = 0 ; }
38. CUT!
39. | t I V A R { $ $ = 0 ; }
40. c l a s s D e f a u l t a t t r _ a c c e s s o r : n a m e d e f i n i t i a l i z e ( @ n a m e ) ; e n d e n d D e f a u l t . n e w . n a m e = > n i l D e f a u l t . n e w ( " R u b y " ) . n a m e # = > m e t h o d ' i n i t i a l i z e ' : g i v e n 1 , # e x p e c t e d 0 ( A r g u m e n t E r r o r )
41. What about AST? " d e f i n i t i a l i z e ( @ n a m e ) ; e n d " . t o _ a s t
42. R u b i n i u s : : A S T : : D e f i n e : 0 x 1 8 4 e c @ a r g u m e n t s = R u b i n i u s : : A S T : : F o r m a l A r g u m e n t s 1 9 : 0 x 1 8 4 f 0 @ l i n e = 1 @ d e f a u l t s = n i l # I M P O R T A N T L I N E ! @ s p l a t = n i l @ n a m e s = [ ] @ o p t i o n a l = [ ] @ r e q u i r e d = [ ] > @ b o d y = R u b i n i u s : : A S T : : B l o c k : 0 x 1 8 4 f 8 @ a r r a y = [ R u b i n i u s : : A S T : : N i l L i t e r a l : 0 x 1 8 5 0 0 @ l i n e = 1 > ] @ l o c a l s = n i l > @ n a m e = : i n i t i a l i z e >
43. AST for default argument " d e f i n i t i a l i z e ( n a m e = n i l ) ; e n d " . t o _ a s t
44. AST for default argument R u b i n i u s : : A S T : : D e f i n e : 0 x 1 8 4 e c @ a r g u m e n t s = R u b i n i u s : : A S T : : F o r m a l A r g u m e n t s 1 9 : 0 x 1 8 4 f 0 @ d e f a u l t s = R u b i n i u s : : A S T : : D e f a u l t A r g u m e n t s : 0 x 3 3 4 5 0 @ a r g u m e n t s = [ R u b i n i u s : : A S T : : L o c a l V a r i a b l e A s s i g n m e n t : 0 x 3 3 4 5 c @ n a m e = : n a m e @ v a l u e = R u b i n i u s : : A S T : : N i l L i t e r a l : 0 x 3 3 4 6 0 @ l i n e = 1 ] > @ n a m e s = [ : n a m e ] @ o p t i o n a l = [ : n a m e ] @ b o d y = R u b i n i u s : : A S T : : B l o c k : 0 x 1 8 4 f 8 @ a r r a y = [ R u b i n i u s : : A S T : : N i l L i t e r a l : 0 x 1 8 5 0 0 @ l i n e = 1 ] @ n a m e = : i n i t i a l i z e >
45. Debug def method(@name) == def method(name)
46. Debug c l a s s F o r m a l A r g u m e n t s 1 9 < F o r m a l A r g u m e n t s d e f i n i t i a l i z e ( l i n e , r e q u i r e d , o p t i o n a l , s p l a t , p o s t , b l o c k ) r e q u i r e d . i n s p e c t = > [ f a l s e ] # f a l s e ? ! # c o d e . . . e n d e n d
48. $$ = 0 | t I V A R { $ $ = 0 ; } | t I V A R { $ $ = $ 1 ; }
49. Debug After this change, everything starts to work. c l a s s F o r m a l A r g u m e n t s 1 9 < F o r m a l A r g u m e n t s d e f i n i t i a l i z e ( l i n e , r e q u i r e d , o p t i o n a l , s p l a t , p o s t , b l o c k ) r e q u i r e d . i n s p e c t = > [ : @ n a m e ] # Y E S ! # c o d e . . . e n d e n d
50. :@name => :name i f a r g . t o _ s = ~ / ^ @ / d e f a u l t s < < a r g . t o _ s [ 1 . . - 1 ] . t o _ s y m e n d
51. Empty method d e f i n i t i a l i z e ( @ n a m e ) ; e n d c l a s s B l o c k i f b l o c k . a r r a y . e m p t y ? b l o c k . a r r a y < < N i l L i t e r a l . n e w ( l i n e ) e n d e n d
52. Custom empty method d e f i n i t i a l i z e ( @ n a m e ) @ n a m e = n a m e e n d i f @ a r g u m e n t s . d e f a u l t _ v a r i a b l e s @ a r g u m e n t s . d e f a u l t s . n a m e s . e a c h d o | a r g _ n a m e | b l o c k . a r r a y . u n s h i f t ( I n s t a n c e V a r i a b l e A s s i g n m e n t . n e w ( l i n e , " @ # { a r g _ n a m e } " . t o _ s y m , L o c a l V a r i a b l e A c c e s s . n e w ( l i n e , a r g _ n a m e ) ) ) e n d e l s i f b l o c k . a r r a y . e m p t y ? b l o c k . a r r a y < < N i l L i t e r a l . n e w ( l i n e ) e n d
53. DEMO
54. Impossible is nothing
55. How to include class $ g e m i n s t a l l i n c l u d e r e q u i r e ' i n c l u d e ' c l a s s M y C l a s s i n c l u d e A r r a y . t o _ m e n d
56. Thx Piotr Nielacny / @piterniel