Ruby module to generate HTML tables

maketable.rb

require 'cgi'
require 'date'

module MakeTable
extend self

  Tabletags = [%w[th td], "tr", "table"]

  CSS = <<EOS
  table,th,td {
    border-collapse:collapse;
    border:1px solid black;
  }
  th,td {
    padding:5px;
  }
EOS

  def maketag tree, tags, i=0, indent="  "
    if Array === tree
      tree = tree.map.with_index { |e,j|
        maketag e, tags[0...-1].map { |t| Array === t ? t[[j,t.size-1].min] : t }, i+1, indent
      }.join
    elsif tags.empty?
      raise "tag underflow"
    end
    pad = "\n" + indent * i
    # Use some whitespace heuristic to find out
    # if we wrapping raw text or formatted output
    # of an earlier invocations of maketag. Hacky,
    # but good for now.
    tree =  tree =~ /^\s|\n/ ?
         "#{tree}#{pad}" :
         CGI.escapeHTML(tree.to_s)
    tag = tags[-1]
    "#{pad}<#{tag}>#{tree}</#{tag.sub(/\s.*/, "")}>"
  end

  def normalize_row row, header
    row = row.values_at *header if Hash === row
    return row unless row.size == 2
    label, fields = row
    case fields
    when Array
      [label] + fields
    when Hash
      [label] + header[1..-1].map { |h| fields[h] }
    when String, Numeric, Time, Date, Symbol, false, true, nil
      row
    else
      [label] + header[1..-1].map { |h| fields.respond_to?(h) ? fields.send(h) : nil }
    end
  end

  def maketable rows, header, indentlevel:0, indent:"  ", standalone:false, css:CSS
    table = maketag [header] + rows.map{|r| normalize_row r, header}, Tabletags,
            indentlevel + (standalone ? 2 : 0), indent
    return table unless standalone

    maketag [
      [[css], ['style type="text/css" media="screen"', "head"]],
      [table, ["body"]]
    ].map { |td| maketag *(td + [indentlevel + 1, indent]) }.join, ["html"], indentlevel, indent
  end

end

class Array
  def wrep *a
    open("|w3m -dump -T text/html #{ENV["W3MOPTS"]}", "w"){|f|
      f << MakeTable.maketable(map.with_index{|e,i|[i,e]}, ["", a].flatten, standalone:true)
    }
  end
end