gistfile1.js

start
  = (d:die _ { return d })*

number
  = [0-9]

nonzero
  = [1-9]

diesize
  = 'd' int:integer                     { return int; }

modifier
  = '+' int:integer                     { return int; }
  / '-' int:integer                     { return -1 * int; }

die
  = cnt:integer? sz:diesize mod:modifier?   { return { count: cnt || 1, size: sz, adjust: mod || 0 }; }

integer
  = nz:nonzero num:number*              { return parseInt(nz + num.join(''), 10); }

// optional whitespace
_  = [ \t\r\n]*