mdtable: Clean up Markdown tables in code comments and Markdown files

mdtable.rb

#!/usr/bin/env ruby

require 'find'

def parse_cells(row)
  row.split('|').map(&:strip)[1..-1]
end

def header?(cells)
  cells.all? { |cell| cell =~ /^:?\-+:?$/ }
end
def build_table(table, commented, indent, header)
  widths = [0]*table.first.size
  table.each do |row|
    row.each_with_index do |cell, col|
      widths[col] = cell.size if widths[col] < cell.size
    end
  end
  
  string = ""
  
  first_row = header ? table.shift : ['']*table.first.size
  render_preamble string, indent, commented
  render_row first_row, string, widths
  render_preamble string, indent, commented
  render_header header, string, widths
  
  table.each do |row|
    render_preamble string, indent, commented
    render_row row, string, widths
  end
  
  string
end

def render_preamble(string, indent, commented)
  string << ' '*indent
  string << '# ' if commented
  string << '|'
end

def render_row(row, string, widths)
  row.zip(widths).each do |(cell, width)|
    string << ' ' << cell.ljust(width, ' ') << ' ' << '|'
  end
  string << "\n"
end

def render_header(header, string, widths)
  header ||= [:left]*widths.size
  header.zip(widths).each do |(align, width)|
    string << ':' if align == :left
    string << '-'*(width + (align == :center ? 2 : 1))
    string << ':' if align == :right
    string << '|'
  end
  string << "\n"
end

def process_file(file, comments_only=nil)
  output = ""
  table = nil
  commented = nil
  indent = nil
  header = nil
  output = String.new
  
  file.each_line do |line|
    rx = if comments_only
      /^(\s*)# (\|(.+?\|)+)\s*$/
    elsif comments_only == false
      /^(\s*)(\|(.+?\|)+)\s*$/
    elsif comments_only.nil?
      /^(\s*)(?:# )?(\|(.+?\|)+)\s*$/
    end
    
    if line =~ rx
      table ||= []
      commented = line.strip[0, 1] == '#'
      indent ||= $1.size
    
      cells = parse_cells($2)
      if header?(cells)
        header ||= cells.map do |cell|
          if cell[0, 1] == ':' then :left
          elsif cell[-1, 1] == ':' then :right
          else :center end
        end
      else
        table << cells
      end
    elsif table
      output << build_table(table, commented, indent, header) << line
      table = commented = indent = header = nil
    else
      output << line
    end
  end
  output
end

if ARGV.all? { |v| File.directory? v }
  ARGV.each do |dir|
    Find.find(File.join(Dir.getwd, dir)) do |path|
      if File.directory?(path) && path[0, 1] == '.' && path != '.'
        Find.prune
      elsif %w( .rb .md ).include?(File.extname(path)) && !File.symlink?(path)
        content = File.read(path)
        File.open(path, 'w') { |f| f.puts process_file(content, File.extname(path) == '.rb') }
      end
    end
  end
elsif ARGV.none? { |v| File.directory? v }
  puts process_file(ARGF)
else
  raise "Must provide a list of files or a list of directories"
end