| Class | Description | 
|---|---|
| BlockEnvironment | |
| DebugEnvironment | 
 Read-only environment based on a frame descriptor used to give debugger code access to the
 lexical environment it's to be evaluated in. 
 | 
| Environment | |
| Environment.VarRef | |
| EvalEnvironment | |
| FunctionEnvironment | |
| GlobalEnvironment | |
| WithEnvironment | 
 This environment stores "with" blocks. 
 |