scala/env.scala

   1 import types._list
   2
   3 import scala.collection.mutable
   4
   5 object env {
   6   class Env(outer: Env = null,
   7             binds: Iterator[Any] = null,
   8             exprs: Iterator[Any] = null) {
   9     val data: mutable.Map[Symbol, Any] = mutable.Map()
  10     if (binds != null && exprs != null) {
  11       binds.foreach(b => {
  12         val k = b.asInstanceOf[Symbol]
  13         if (k == '&) {
  14           data(binds.next().asInstanceOf[Symbol]) = _list(exprs.toSeq:_*)
  15         } else {
  16           data(k) = exprs.next()
  17         }
  18       })
  19     }
  20
  21     def find(key: Symbol): Env = {
  22         if (data.contains(key)) {
  23             this
  24         } else if (outer != null) {
  25             outer.find(key)
  26         } else {
  27             null
  28         }
  29     }
  30     def set(key: Symbol, value: Any): Any = {
  31         data(key) = value
  32         value
  33     }
  34     def get(key: Symbol): Any = {
  35         val env = find(key)
  36         if (env == null) throw new Exception("'" + key.name + "' not found")
  37         env.data(key)
  38     }
  39   }
  40 }
  41
  42 // vim:ts=2:sw=2