python/env.py

   1 # Environment
   2
   3 class Env():
   4     def __init__(self, outer=None, binds=None, exprs=None):
   5         self.data = {}
   6         self.outer = outer or None
   7
   8         if binds:
   9             for i in range(len(binds)):
  10                 if binds[i] == "&":
  11                     self.data[binds[i+1]] = exprs[i:]
  12                     break
  13                 else:
  14                     self.data[binds[i]] = exprs[i]
  15
  16     def find(self, key):
  17         if key in self.data: return self
  18         elif self.outer:     return self.outer.find(key)
  19         else:                return None
  20
  21     def set(self, key, value):
  22         self.data[key] = value
  23         return value
  24
  25     def get(self, key):
  26         env = self.find(key)
  27         if not env: raise Exception("'" + key + "' not found")
  28         return env.data[key]