# File lib/math_ml/latex.rb, line 304 def expand_command(com, params, opt=nil) return nil unless @commands.has_key?(com) c = @commands[com] opt = c.option if c.option && !opt params.unshift(opt) if c.option raise ParseError.new("Need more parameter.") if params.size < c.num c.body.gsub(/(#{MBEC}*?)\#(\d+)/) do $1.to_s << params[$2.to_i-1] end end