parameters: (self, env, vars_lst)
return_statement: return ret
docstring: Hashes configuration set variables::
  
  			def build(bld):
  				bld.hash_env_vars(bld.env, ['CXX', 'CC'])
  
  		This method uses an internal cache.
  
  		:param env: Configuration Set
  		:type env: :py:class:`waflib.ConfigSet.ConfigSet`
  		:param vars_lst: list of variables
  		:type vars_list: list of string
docstring_summary: Hashes configuration set variables::
docstring_tokens: Hashes configuration set variables ::
function: def hash_env_vars(self, env, vars_lst):
  		"""
  		Hashes configuration set variables::
  
  			def build(bld):
  				bld.hash_env_vars(bld.env, ['CXX', 'CC'])
  
  		This method uses an internal cache.
  
  		:param env: Configuration Set
  		:type env: :py:class:`waflib.ConfigSet.ConfigSet`
  		:param vars_lst: list of variables
  		:type vars_list: list of string
  		"""
  
  		if not env.table:
  			env = env.parent
  			if not env:
  				return Utils.SIG_NIL
  
  		idx = str(id(env)) + str(vars_lst)
  		try:
  			cache = self.cache_env
  		except AttributeError:
  			cache = self.cache_env = {}
  		else:
  			try:
  				return self.cache_env[idx]
  			except KeyError:
  				pass
  
  		lst = [env[a] for a in vars_lst]
  		cache[idx] = ret = Utils.h_list(lst)
  		Logs.debug('envhash: %s %r', Utils.to_hex(ret), lst)
  		return ret
function_tokens: def hash_env_vars ( self , env , vars_lst ) : if not env . table : env = env . parent if not env : return Utils . SIG_NIL idx = str ( id ( env ) ) + str ( vars_lst ) try : cache = self . cache_env except AttributeError : cache = self . cache_env = { } else : try : return self . cache_env [ idx ] except KeyError : pass lst = [ env [ a ] for a in vars_lst ] cache [ idx ] = ret = Utils . h_list ( lst ) Logs . debug ( 'envhash: %s %r' , Utils . to_hex ( ret ) , lst ) return ret