Contents

class Spreadshit
  require "spreadshit/cell"
  require "spreadshit/formula"
  require "spreadshit/functions"

  def initialize(parser = Formula.new, functions = Functions.new)
    @cells = Hash.new { |hash, key| hash[key] = Cell.new }
    @parser = parser
    @functions = functions
  end

  def [](address)
    @cells[address.to_sym].value
  end

  def []=(address, value)
    @cells[address.to_sym].update(value) { parse(value) }
  end

  def cell_at(address)
    @cells[address.to_sym]
  end

  private

  def parse(value)
    if value.to_s.start_with? "="
      eval @parser.parse(value[1..-1])
    else
      value
    end
  end

  def eval(expression, refs = Set.new)
    case expression
    when Formula::Literal
      expression.content
    when Formula::Addition
      @functions.add(eval(expression.left, refs), eval(expression.right, refs))
    when Formula::Subtraction
      @functions.minus(eval(expression.left, refs), eval(expression.right, refs))
    when Formula::Multiplication
      @functions.multiply(eval(expression.left, refs), eval(expression.right, refs))
    when Formula::Division
      @functions.divide(eval(expression.left, refs), eval(expression.right, refs))
    when Formula::Function
      @functions.send(expression.name.downcase, *expression.arguments.map { |arg| eval arg, refs })
    when Formula::Reference
      if refs.include? expression.address
        "CYCLIC"
      else
        refs << expression.address
        self[expression.address]
      end
    when Formula::Range
      expand_range(expression.top, expression.bottom).map { |ref| eval ref, refs }
    end
  end

  def expand_range(top, bottom)
    cols = top.col..bottom.col
    rows = top.row..bottom.row
    cols.flat_map do |col|
      rows.map { |row| Formula::Reference.new(col, row) }
    end
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
spreadshit-0.1.1	lib/spreadshit.rb