A seriously (if I may say so) kick-ass implementation of a dice notation reader in coffeescript.

dice.coffee

##
A seriously (if I may say so) kick-ass implementation of a dice notation reader in coffeescript. 
Careful, it evals code, keep your strings clean before feeding them to this baby! (and adds a "d" method to Number)
##
Number::d = ( v )->
    [1..@].reduce ( a )-> 
        a + ( Math.floor( Math.random()*v ) + 1 )
    , 0
    
Dice = ( dice )->
    unless @ instanceof Dice then return new Dice(dice) 
    @src = dice.replace( /x/gi, '*' )
               .replace( /d(\%|00)(\D|$)/g, "d100$2" )
               .replace( /d(\d+)/g, "d($1)" )
               .replace( /(\d+|\))d/g, "($1).d" )
               .replace( /\d+/g, ( n )-> n.replace /^0+/g, '' )
               .replace( /\(\)/g, '' ) 
    # console.log @src
    @dice = new Function( 'd','n', "return function(){ return #{@src};}")
            .apply null, [
                ( v )-> (1).d( v )
            ]
    @roll = ( repeats )->
        repeats||=1
        value = 0
        while repeats > 0
            value += @dice()
            repeats--
        value
    return @

module.exports = Dice

# example:
#   console.log Dice('1d6+3').roll()