yorick/env.i

   1 require, "hash.i"
   2 require, "types.i"
   3
   4 struct Env {
   5   pointer outer
   6   Hash data
   7 }
   8
   9 func env_new(outer_ptr, binds=, exprs=)
  10 {
  11   env = Env(outer=outer_ptr, data=hash_new())
  12   for (i = 1; i <= numberof(binds); ++i) {
  13     if (binds(i)->val == "&") {
  14       rest_args = numberof(exprs) >= i ? exprs(i:) : []
  15       env_set, env, binds(i + 1)->val, MalList(val=&rest_args)
  16       break
  17     } else {
  18       env_set, env, binds(i)->val, *exprs(i)
  19     }
  20   }
  21   return env
  22 }
  23
  24 func env_find(env, key)
  25 {
  26   if (hash_has_key(env.data, key)) return env
  27   if (is_void(*env.outer)) return nil
  28   return env_find(*env.outer, key)
  29 }
  30
  31 func env_get(env, key)
  32 {
  33   found_env = env_find(env, key)
  34   if (is_void(found_env)) return MalError(message=("'" + key + "' not found"))
  35   return hash_get(found_env.data, key)
  36 }
  37
  38 func env_set(&env, key, val)
  39 {
  40   d = env.data
  41   hash_set, d, key, val
  42   env.data = d
  43   return val
  44 }