ascii table generating class

table_format.rb

# Should really make a note here:
# This class currently only accepts arrays of data that has separators, rather than being a two-dimensional array. This will be fixed at some point.
# It will also not take a single string, or other types of collections. This will also be fixed at some point (in that case, table headings would have to be revamped to allow key->value pairings.
# - Mark

# -*- coding: utf-8 -*-
require 'active_support/core_ext/object/blank'

module Helpers
  # Formats a supplied array into a list or table.
  # @author Mark Seymour ('Azure') (mark.seymour.ns@gmail.com)
  # 
  # @param [Array] The source array.
  # @param [Hash] params Options for generating the table.
  # @option params [String] :splitchars ('\t') Characters to split each individual item on.
  # @option params [Regexp] :regexp (nil) A Regexp to split each individual item on. If one is supplied, then :splitchars is ignored.
  # @option params [Array] :justify ([:left]) Changes the justification of individual table items. If there are more headers set than column justifications, the default will be used. Valid options are :left or :right.
  # @option params [Array] :headers ([]) Sets the names for the table column headers. If left unset, no headers will be generated.
  # @option params [Integer] :gutter (4) Sets the gutter size between columns and optionally the left gutter.
  # @option params [Boolean] :left_gutter (false) Generates a gutter on the left side of the generated table, equal to the same length as column gutters.
  # @option params [Boolean] :display_indices (false) Shows the index #+1 of the row.
  # @option params [Boolean] :display_noitems (true) Displays a notice if there are no items to show.
  # @option params [String] :noitems_msg ("There is nothing to show.") Sets the message for display_noitems.
  # @option params [Boolean] :display_eot (true) Displays a notice at the end of the table.
  # @option params [String] :eot_msg ("End of results.") Sets the message for display_eot.
  # @todo Have the ability to output either an array or string (params[:array]?)
  # @return [String] The formatted string with line endings.
  def Helpers.table_format array, params={}
    params = {
      splitchars: "\t", 
      regexp: nil,
      justify: [:left], # :left, :right
      headers: [], # ary (ex: ["a","b","c"])
      gutter: 4,
      left_gutter: false,
      display_indices: false,
      display_noitems: true,
      noitems_msg: "There is nothing to show.",
      display_eot: true,
      eot_msg: "End of results."
    }.merge!(params)
    
    source = array.dup # We cannot be altering our original object now, can we?

    # We use the str.tr method if our regexp param is nil.
    # Otherwise, we just use regexp.
    source.map! {|e| params[:regexp].nil? ? e.tr(params[:splitchars], "\t").split("\t") : e.match(params[:regexp])[1..-1].map {|e| e.nil? ? "" : e; } }

    # calculating the maximum length of each column
    column_lengths = []
   
   # optional index
    if params[:display_indices]
      params[:justify].unshift(:right)
      params[:headers].unshift("#")
      source.each_with_index.map {|e,i| e.unshift(i.succ)}
    end

    source.dup.unshift(params[:headers]).each {|e| 
      e.each_with_index {|item,index| 
        column_lengths[index] = [] if column_lengths[index].blank?
        column_lengths[index] << item.size 
      }
    }
    column_lengths.map! {|e| e.sort.last }

    data = []

    # Generating table headers
    if !params[:headers].blank?
      # Generating the headers, separators, etc.
      s_header = []
      s_separator = s_header.dup
      params[:headers].each_with_index {|e,i|
        s_header << "%#{"-" if params[:justify][i] == :left || params[:justify][i].nil?}#{column_lengths[i]}s" % e.to_s
        s_separator << "-"*column_lengths[i]
      }
      data << s_header.join(" "*params[:gutter]) << s_separator.join(" "*params[:gutter])
    end

    # Generating formatted table rows
    source.each {|e|
      line = []
      e.each_with_index {|item,index|
        line << "%#{"-" if params[:justify][index] == :left || params[:justify][index].nil?}#{column_lengths[index]}s" % item.to_s
      }
      data << line.join(" "*params[:gutter])
    }

    # Adding noitems_msg if there are well... no items.
    if source.empty? && params[:display_noitems] then data << params[:noitems_msg] end
    
    # Adding EOT message
    if params[:display_eot]
      data << "-" * params[:eot_msg].length
      data << params[:eot_msg]
    end

    # Adding a gutter to the left side
    if params[:left_gutter] === true then data.map! {|e| " "*params[:gutter] + e } end
    
    data.join("\n")
  end
end

=begin
my_array = ["column 1 r1 aa\tcolumn 2 r1 aaa\tcolumn 3 r1 aaaa",
            "column 1 r2 bbbb\tcolumn 2 r2 b\tcolumn 3 r2 bbbbbbbbb",
            "column 1 r3\tcolumn 2 r3 ffffffffff\tcolumn 3 r3 fff"]

puts Helpers.table_format my_array, justify: [:right,:left,:right], gutter: 2, headers: ["column 1","column 2","column3"], display_indices: true
=end