GitHub - levinalex/tablemaker: Create nested HTML tables without manually keeping track of colspan/rowspan.

HTML table generator that allows arbitrary nested cell subdivisions and applies colspan/rowspan as needed.

Including the gem in your Rails project will give you a new view helper make_table

Usage

= make_table(class: 'foo') do |t|
  - t.row do
    - t.th("A")
    - t.th("B")
    - t.th("C")
  - t.row do
    - t.column do
      - t.td("E")
      - t.td("F)
  - t.td(style: 'background: green') do
    %p cell content

this will generate this output:

source:

<table class='foo'>
  <tr>
    <td>A</td>
    <td>B</td>
    <td>C</td>
  </tr>
  <tr>
    <td>E</td>
    <td style='background: green' rowspan='2' colspan='2'>
      <p>cell centent</p>
    </td>
  </tr>
  <tr>
    <td>F</td>
  </tr>
</table>

Examples outside Rails

A very basic table:

# +---+---+
# | A | B |
# +---+---+
# | C | D |
# +---+---+
#
@table2 = Tablemaker.column do |c|
  c.row do |r|
    r.cell("A")
    r.cell("B")
  end
  c.row do |r|
    @c2 = r.cell("C")
    @d2 = r.cell("D")
  end
end

# but you can also start with columns and construct the table left-to-right. this produces the exact same result:
#
Tablemaker.row do |r|
  r.column do |c|
    c.cell("A")
    c.cell("C")
  end
  r.column do |c|
    c.cell("B")
    c.cell("D")
  end
end

A more advanced example:

# +---+---+---+
# |   | B |   |
# |   +---+ C |
# |   | D |   |
# | A +---+---+
# |   |   | F |
# |   | E +---+
# |   |   | G |
# +---+---+---+
#
@table = Tablemaker.row do |t|
  t.cell("A")
  t.column do |r|
    r.row do |c|
      c.column do |rr|
        rr.cell("B")
        rr.cell("D")
      end
      c.cell("C")
    end
    r.row do |c|
      c.cell("E")
      c.column do |rr|
        rr.cell("F")
        rr.cell("G")
      end
    end
  end
end

this will generate the following output:

A	B	D
		E
	C	F
		G

Tablemaker keeps track of all the rowspan/colspan attributes required to generate a valid HTML table