Ruby modules. RRUG #1

Uses of Ruby modules. Presentation given during the first meeting of Rzeszów Ruby User Group.

Main uses are: namespacing, mixins, singletons and limited monkeypatching.

Based on: http://practicingruby.com/articles/uses-for-modules-1 (esp. the PDF version)

Transcript

1. RUBY MODULES
   RZESZÓW RUBY USER GROUP #1
   20.10.2016
   Maciej Rząsa
   PGS Software
   @mjrzasa
   

   View Slide

2. Zastosowanie
   namespace
   mixin
   singleton
   ograniczony monkey patching
   

   View Slide

3. NAMESPACE
   # G
   r
   a
   p
   h l
   i
   b
   r
   a
   r
   y
   c
   l
   a
   s
   s N
   o
   d
   e
   # .
   .
   .
   e
   n
   d
   # X
   M
   L l
   i
   b
   r
   a
   r
   y
   c
   l
   a
   s
   s N
   o
   d
   e
   # .
   .
   .
   e
   n
   d
   N
   o
   d
   e
   .
   n
   e
   w
   źródło: youtube.com
   

   View Slide

4. NAMESPACE
   # G
   r
   a
   p
   h l
   i
   b
   r
   a
   r
   y
   m
   o
   d
   u
   l
   e G
   r
   a
   p
   h
   c
   l
   a
   s
   s N
   o
   d
   e
   # .
   .
   .
   e
   n
   d
   e
   n
   d
   # X
   M
   L l
   i
   b
   r
   a
   r
   y
   m
   o
   d
   u
   l
   e X
   M
   L
   c
   l
   a
   s
   s N
   o
   d
   e
   # .
   .
   .
   e
   n
   d
   e
   n
   d
   G
   r
   a
   p
   h
   :
   :
   N
   o
   d
   e
   .
   n
   e
   w
   X
   M
   L
   :
   :
   N
   o
   d
   e
   .
   n
   e
   w
   

   View Slide

5. MIXIN
   

   View Slide

6. INCLUDE
   m
   o
   d
   u
   l
   e G
   r
   e
   e
   t
   e
   r
   d
   e
   f s
   a
   y
   _
   h
   e
   l
   l
   o
   p
   u
   t
   s "
   H
   e
   l
   l
   o
   !
   "
   e
   n
   d
   e
   n
   d
   c
   l
   a
   s
   s P
   e
   r
   s
   o
   n
   i
   n
   c
   l
   u
   d
   e G
   r
   e
   e
   t
   e
   r
   e
   n
   d
   p
   e
   r
   s
   o
   n = P
   e
   r
   s
   o
   n
   .
   n
   e
   w
   p
   e
   r
   s
   o
   n
   .
   s
   a
   y
   _
   h
   e
   l
   l
   o
   # > "
   H
   e
   l
   l
   o
   !
   "
   

   View Slide

7. EXTEND CLASS
   c
   l
   a
   s
   s P
   e
   r
   s
   o
   n
   e
   x
   t
   e
   n
   d G
   r
   e
   e
   t
   e
   r
   e
   n
   d
   P
   e
   r
   s
   o
   n
   .
   s
   a
   y
   _
   h
   e
   l
   l
   o
   # > "
   H
   e
   l
   l
   o
   !
   "
   P
   e
   r
   s
   o
   n
   .
   n
   e
   w
   .
   s
   a
   y
   _
   h
   e
   l
   l
   o
   # 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 `
   s
   a
   y
   _
   h
   e
   l
   l
   o
   '
   .
   .
   .
   

   View Slide

8. EXTEND OBJECT
   p
   e
   r
   s
   o
   n
   1 = P
   e
   r
   s
   o
   n
   .
   n
   e
   w
   p
   e
   r
   s
   o
   n
   2 = P
   e
   r
   s
   o
   n
   .
   n
   e
   w
   p
   e
   r
   s
   o
   n
   1
   .
   e
   x
   t
   e
   n
   d
   (
   G
   r
   e
   e
   t
   e
   r
   )
   p
   e
   r
   s
   o
   n
   1
   .
   s
   a
   y
   _
   h
   e
   l
   l
   o
   # > "
   H
   e
   l
   l
   o
   !
   "
   p
   e
   r
   s
   o
   n
   2
   .
   s
   a
   y
   _
   h
   e
   l
   l
   o
   # 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 `
   s
   a
   y
   _
   h
   e
   l
   l
   o
   '
   .
   .
   .
   

   View Slide

9. 1.6
   1.6
   1.6
   1.6
   1.6
   1.6
   1.6
   1.6
   1.6
   1.6
   1.6
   CONCERN
   m
   o
   d
   u
   l
   e S
   o
   f
   t
   D
   e
   l
   e
   t
   e
   d
   e
   f d
   e
   l
   e
   t
   e
   @
   d
   e
   l
   e
   t
   e
   d
   _
   a
   t = T
   i
   m
   e
   .
   n
   o
   w
   s
   a
   v
   e
   e
   n
   d
   d
   e
   f d
   e
   l
   e
   t
   e
   d
   ?
   !
   @
   d
   e
   l
   e
   t
   e
   d
   _
   a
   t
   .
   n
   i
   l
   ?
   e
   n
   d
   m
   o
   d
   u
   l
   e C
   l
   a
   s
   s
   M
   e
   t
   h
   o
   d
   s
   d
   e
   f d
   e
   l
   e
   t
   e
   d
   w
   h
   e
   r
   e
   (
   '
   d
   e
   l
   e
   t
   e
   d I
   S N
   O
   T N
   U
   L
   L
   '
   )
   e
   n
   d
   e
   n
   d
   e
   n
   d
   c
   l
   a
   s
   s P
   e
   r
   s
   o
   n
   i
   n
   c
   l
   u
   d
   e S
   o
   f
   t
   D
   e
   l
   e
   t
   e
   e
   x
   t
   e
   n
   d S
   o
   f
   t
   D
   e
   l
   e
   t
   e
   :
   :
   C
   l
   a
   s
   s
   M
   e
   t
   h
   o
   d
   s
   e
   n
   d
   p = P
   e
   r
   s
   o
   n
   .
   a
   c
   t
   i
   v
   e
   .
   f
   i
   r
   s
   t
   p
   .
   d
   e
   l
   e
   t
   e
   d
   ?
   1.6
   1.6
   1.6
   1.6
   1.6
   1.6
   

   View Slide

10. 1.6
    1.6
    1.6
    1.6
    1.6
    1.6
    1.6
    1.6
    1.6
    1.6
    1.6
    1.6
    CONCERN: INCLUDED
    m
    o
    d
    u
    l
    e S
    o
    f
    t
    D
    e
    l
    e
    t
    e
    d
    e
    f s
    e
    l
    f
    .
    i
    n
    c
    l
    u
    d
    e
    d
    (
    b
    a
    s
    e
    )
    s
    e
    l
    f
    .
    e
    x
    t
    e
    n
    d
    (
    C
    l
    a
    s
    s
    M
    e
    t
    h
    o
    d
    s
    )
    e
    n
    d
    d
    e
    f d
    e
    l
    e
    t
    e
    @
    d
    e
    l
    e
    t
    e
    d
    _
    a
    t = T
    i
    m
    e
    .
    n
    o
    w
    s
    a
    v
    e
    e
    n
    d
    d
    e
    f d
    e
    l
    e
    t
    e
    d
    ?
    !
    @
    d
    e
    l
    e
    t
    e
    d
    _
    a
    t
    .
    n
    i
    l
    ?
    e
    n
    d
    m
    o
    d
    u
    l
    e C
    l
    a
    s
    s
    M
    e
    t
    h
    o
    d
    s
    d
    e
    f d
    e
    l
    e
    t
    e
    d
    w
    h
    e
    r
    e
    (
    '
    d
    e
    l
    e
    t
    e
    d I
    S N
    O
    T N
    U
    L
    L
    '
    )
    e
    n
    d
    e
    n
    d
    e
    n
    d
    c
    l
    a
    s
    s P
    e
    r
    s
    o
    n
    i
    n
    c
    l
    u
    d
    e S
    o
    f
    t
    D
    e
    l
    e
    t
    e
    e
    n
    d
    p = P
    e
    r
    s
    o
    n
    .
    a
    c
    t
    i
    v
    e
    .
    f
    i
    r
    s
    t
    p
    .
    d
    e
    l
    e
    t
    e
    d
    ?
    1.6
    1.6
    1.6
    1.6
    1.6
    

    View Slide

11. CONCERN: ACTIVE SUPPORT
    m
    o
    d
    u
    l
    e S
    o
    f
    t
    D
    e
    l
    e
    t
    e
    e
    x
    t
    e
    n
    d A
    c
    t
    i
    v
    e
    S
    u
    p
    p
    o
    r
    t
    :
    :
    C
    o
    n
    c
    e
    r
    n
    d
    e
    f d
    e
    l
    e
    t
    e
    @
    d
    e
    l
    e
    t
    e
    d
    _
    a
    t = T
    i
    m
    e
    .
    n
    o
    w
    s
    a
    v
    e
    e
    n
    d
    d
    e
    f d
    e
    l
    e
    t
    e
    d
    ?
    !
    @
    d
    e
    l
    e
    t
    e
    d
    _
    a
    t
    .
    n
    i
    l
    ?
    e
    n
    d
    m
    o
    d
    u
    l
    e C
    l
    a
    s
    s
    M
    e
    t
    h
    o
    d
    s
    d
    e
    f d
    e
    l
    e
    t
    e
    d
    w
    h
    e
    r
    e
    (
    '
    d
    e
    l
    e
    t
    e
    d I
    S N
    O
    T N
    U
    L
    L
    '
    )
    e
    n
    d
    e
    n
    d
    e
    n
    d
    c
    l
    a
    s
    s P
    e
    r
    s
    o
    n
    i
    n
    c
    l
    u
    d
    e S
    o
    f
    t
    D
    e
    l
    e
    t
    e
    e
    n
    d
    p = P
    e
    r
    s
    o
    n
    .
    a
    c
    t
    i
    v
    e
    .
    f
    i
    r
    s
    t
    p
    .
    d
    e
    l
    e
    t
    e
    d
    ?
    

    View Slide

12. MIXINY: ZASTOSOWANIE
    E
    n
    u
    m
    e
    r
    a
    b
    l
    e C
    o
    m
    p
    a
    r
    a
    b
    l
    e
    soft delete
    cache key
    

    View Slide

13. SINGLETON
    m
    o
    d
    u
    l
    e M
    a
    t
    h
    d
    e
    f p
    o
    w
    e
    r
    (
    x
    , e
    )
    x
    *
    *
    e
    e
    n
    d
    e
    n
    d
    m
    o
    d
    u
    l
    e M
    a
    t
    h
    O
    p
    e
    r
    a
    t
    i
    o
    n
    s
    e
    x
    t
    e
    n
    d M
    a
    t
    h
    e
    n
    d
    M
    a
    t
    h
    O
    p
    e
    r
    a
    t
    i
    o
    n
    s
    .
    p
    o
    w
    (
    2
    , 3
    )
    m
    o
    d
    u
    l
    e M
    a
    t
    h
    e
    x
    t
    e
    n
    d M
    a
    t
    h
    d
    e
    f p
    o
    w
    e
    r
    (
    x
    , e
    )
    x
    *
    *
    e
    e
    n
    d
    e
    n
    d
    M
    a
    t
    h
    .
    p
    o
    w
    (
    2
    , 3
    )
    m
    o
    d
    u
    l
    e M
    a
    t
    h
    e
    x
    t
    e
    n
    d s
    e
    l
    f
    d
    e
    f p
    o
    w
    e
    r
    (
    x
    , e
    )
    x
    *
    *
    e
    e
    n
    d
    e
    n
    d
    M
    a
    t
    h
    .
    p
    o
    w
    (
    2
    , 3
    )
    

    View Slide

14. LOKALNY MONKEY PATCHING
    m
    o
    d
    u
    l
    e P
    D
    F
    F
    i
    x
    # f
    i
    x P
    D
    F l
    i
    b
    r
    a
    r
    y b
    u
    g
    e
    n
    d
    c
    l
    a
    s
    s P
    D
    F
    :
    :
    D
    o
    c
    u
    m
    e
    n
    t
    i
    n
    c
    l
    u
    d
    e P
    D
    F
    F
    i
    x
    e
    n
    d
    P
    D
    F
    :
    :
    D
    o
    c
    u
    m
    e
    n
    t
    .
    n
    e
    w
    (
    )
    .
    e
    x
    t
    e
    n
    d
    (
    P
    D
    F
    F
    i
    x
    )
    

    View Slide

15. PODSUMOWANIE
    moduły: organizacja kodu i dziedziczenie
    reużywalność kodu
    trduności w testowaniu (?)
    great power, great responsibility
    Ruby: a programmer's best friend
    źródło: Practicing Ruby (pdf download)
    

    View Slide