RST Reader

```
% pandoc -f rst -t native
=====  =====  ======
   Inputs     Output
------------  ------
  A      B    A or B
=====  =====  ======
False  False  False
True   False  True
False  True   True
True   True   True
=====  =====  ======

Table with trailing whitespaces to ensure they don't interfere with col span parsing.

===============  ============  =====================  
Full column header
---------------------------------------------------- 
Header One       Header Two    Header 3
===============  ============  =====================   
Row              With col span 2 on the right
---------------  -----------------------------------   
Full column row
----------------------------------------------------
Row with         Col spans     For visual separation
---------------  ------------  ---------------------  
Row with col span 2            On the left
-----------------------------  ---------------------
Final row
===============  ============  =====================
^D
[ Table
    ( "" , [] , [] )
    (Caption Nothing [])
    [ ( AlignDefault , ColWidthDefault )
    , ( AlignDefault , ColWidthDefault )
    , ( AlignDefault , ColWidthDefault )
    ]
    (TableHead
       ( "" , [] , [] )
       [ Row
           ( "" , [] , [] )
           [ Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 2)
               [ Plain [ Str "Inputs" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "Output" ] ]
           ]
       , Row
           ( "" , [] , [] )
           [ Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "A" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "B" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "A" , Space , Str "or" , Space , Str "B" ]
               ]
           ]
       ])
    [ TableBody
        ( "" , [] , [] )
        (RowHeadColumns 0)
        []
        [ Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "False" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "False" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "False" ] ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "True" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "False" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "True" ] ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "False" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "True" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "True" ] ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "True" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "True" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "True" ] ]
            ]
        ]
    ]
    (TableFoot ( "" , [] , [] ) [])
, Para
    [ Str "Table"
    , Space
    , Str "with"
    , Space
    , Str "trailing"
    , Space
    , Str "whitespaces"
    , Space
    , Str "to"
    , Space
    , Str "ensure"
    , Space
    , Str "they"
    , Space
    , Str "don't"
    , Space
    , Str "interfere"
    , Space
    , Str "with"
    , Space
    , Str "col"
    , Space
    , Str "span"
    , Space
    , Str "parsing."
    ]
, Table
    ( "" , [] , [] )
    (Caption Nothing [])
    [ ( AlignDefault , ColWidthDefault )
    , ( AlignDefault , ColWidthDefault )
    , ( AlignDefault , ColWidthDefault )
    ]
    (TableHead
       ( "" , [] , [] )
       [ Row
           ( "" , [] , [] )
           [ Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 3)
               [ Plain
                   [ Str "Full"
                   , Space
                   , Str "column"
                   , Space
                   , Str "header"
                   ]
               ]
           ]
       , Row
           ( "" , [] , [] )
           [ Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "Header" , Space , Str "One" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "Header" , Space , Str "Two" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "Header" , Space , Str "3" ] ]
           ]
       ])
    [ TableBody
        ( "" , [] , [] )
        (RowHeadColumns 0)
        []
        [ Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "Row" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 2)
                [ Plain
                    [ Str "With"
                    , Space
                    , Str "col"
                    , Space
                    , Str "span"
                    , Space
                    , Str "2"
                    , Space
                    , Str "on"
                    , Space
                    , Str "the"
                    , Space
                    , Str "right"
                    ]
                ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 3)
                [ Plain
                    [ Str "Full"
                    , Space
                    , Str "column"
                    , Space
                    , Str "row"
                    ]
                ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "Row" , Space , Str "with" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "Col" , Space , Str "spans" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain
                    [ Str "For"
                    , Space
                    , Str "visual"
                    , Space
                    , Str "separation"
                    ]
                ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 2)
                [ Plain
                    [ Str "Row"
                    , Space
                    , Str "with"
                    , Space
                    , Str "col"
                    , Space
                    , Str "span"
                    , Space
                    , Str "2"
                    ]
                ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain
                    [ Str "On"
                    , Space
                    , Str "the"
                    , Space
                    , Str "left"
                    ]
                ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "Final" , Space , Str "row" ] ]
            , Cell
                ( "" , [] , [] ) AlignDefault (RowSpan 1) (ColSpan 1) []
            , Cell
                ( "" , [] , [] ) AlignDefault (RowSpan 1) (ColSpan 1) []
            ]
        ]
    ]
    (TableFoot ( "" , [] , [] ) [])
]
```

RST Writer
```
% pandoc -f native -t rst
[ Table
    ( "" , [] , [] )
    (Caption Nothing [])
    [ ( AlignDefault , ColWidthDefault )
    , ( AlignDefault , ColWidthDefault )
    , ( AlignDefault , ColWidthDefault )
    ]
    (TableHead
       ( "" , [] , [] )
       [ Row
           ( "" , [] , [] )
           [ Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 2)
               [ Plain [ Str "Inputs" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "Output" ] ]
           ]
       , Row
           ( "" , [] , [] )
           [ Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "A" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "B" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "A" , Space , Str "or" , Space , Str "B" ]
               ]
           ]
       ])
    [ TableBody
        ( "" , [] , [] )
        (RowHeadColumns 0)
        []
        [ Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "False" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "False" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "False" ] ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "True" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "False" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "True" ] ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "False" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "True" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "True" ] ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "True" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "True" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "True" ] ]
            ]
        ]
    ]
    (TableFoot ( "" , [] , [] ) [])
, Table
    ( "" , [] , [] )
    (Caption Nothing [])
    [ ( AlignDefault , ColWidthDefault )
    , ( AlignDefault , ColWidthDefault )
    , ( AlignDefault , ColWidthDefault )
    ]
    (TableHead
       ( "" , [] , [] )
       [ Row
           ( "" , [] , [] )
           [ Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 3)
               [ Plain
                   [ Str "Full"
                   , Space
                   , Str "column"
                   , Space
                   , Str "header"
                   ]
               ]
           ]
       , Row
           ( "" , [] , [] )
           [ Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "Header" , Space , Str "One" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "Header" , Space , Str "Two" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "Header" , Space , Str "3" ] ]
           ]
       ])
    [ TableBody
        ( "" , [] , [] )
        (RowHeadColumns 0)
        []
        [ Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "Row" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 2)
                [ Plain
                    [ Str "With"
                    , Space
                    , Str "col"
                    , Space
                    , Str "span"
                    , Space
                    , Str "2"
                    , Space
                    , Str "on"
                    , Space
                    , Str "the"
                    , Space
                    , Str "right"
                    ]
                ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 3)
                [ Plain
                    [ Str "Full"
                    , Space
                    , Str "column"
                    , Space
                    , Str "row"
                    ]
                ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 2)
                [ Plain
                    [ Str "Row"
                    , Space
                    , Str "with"
                    , Space
                    , Str "col"
                    , Space
                    , Str "span"
                    , Space
                    , Str "2"
                    ]
                ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain
                    [ Str "On"
                    , Space
                    , Str "the"
                    , Space
                    , Str "left"
                    ]
                ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "Final" , Space , Str "row" ] ]
            , Cell
                ( "" , [] , [] ) AlignDefault (RowSpan 1) (ColSpan 1) []
            , Cell
                ( "" , [] , [] ) AlignDefault (RowSpan 1) (ColSpan 1) []
            ]
        ]
    ]
    (TableFoot
      ( "" , [] , [] ) 
      [ Row
          ( "" , [] , [] )
          [ Cell
              ( "" , [] , [] )
              AlignDefault
              (RowSpan 1)
              (ColSpan 1)
              [ Plain [ Str "Footer" , Space , Str "Row" ] ]
          , Cell
              ( "" , [] , [] )
              AlignDefault
              (RowSpan 1)
              (ColSpan 1)
              [ Plain [ Str "at" , Space , Str "the" ] ]
          , Cell
              ( "" , [] , [] )
              AlignDefault
              (RowSpan 1)
              (ColSpan 1)
              [ Plain [ Str "bottom" ] ]
          ]
      ])
]
^D
====== ===== ======
Inputs       Output
------------ ------
A      B     A or B
====== ===== ======
False  False False
True   False True
False  True  True
True   True  True
====== ===== ======

=================== ============================ ===========
Full column header                               
------------------------------------------------------------
Header One          Header Two                   Header 3
=================== ============================ ===========
Row                 With col span 2 on the right 
------------------- ----------------------------------------
Full column row                                  
------------------------------------------------------------
Row with col span 2                              On the left
------------------------------------------------ -----------
Final row                                        
Footer Row          at the                       bottom
=================== ============================ ===========
```