skew/env.sk

   1 class Env {
   2   const _outer Env
   3   var _data StringMap<MalVal> = {}
   4
   5   def new(outer Env) {
   6     _outer = outer
   7   }
   8
   9   def new(outer Env, binds List<MalVal>, exprs List<MalVal>) {
  10     _outer = outer
  11     for i in 0..binds.count {
  12       const name = (binds[i] as MalSymbol).val
  13       if name == "&" {
  14         const restName = (binds[i + 1] as MalSymbol).val
  15         _data[restName] = MalList.new(exprs.slice(i))
  16         break
  17       } else {
  18         _data[name] = exprs[i]
  19       }
  20     }
  21   }
  22
  23   def find(key MalSymbol) Env {
  24     if key.val in _data { return self }
  25     return _outer?.find(key)
  26   }
  27
  28   def get(key MalSymbol) MalVal {
  29     const env = find(key)
  30     if env == null { throw MalError.new("'" + key.val + "' not found") }
  31     return env._data[key.val]
  32   }
  33
  34   def set(key MalSymbol, value MalVal) MalVal {
  35     _data[key.val] = value
  36     return value
  37   }
  38 }