| AbsoluteProgress | A progress reporter counting progress in absolute units |
| AbstractProgress | The abstract progress reporter |
| EmptyClass | |
| Executable | A generic executable object |
| Expression | Evaluation of Expressions |
| ExpressionContext | Represents the context of an expression evaluation |
| GlobPattern | A glob pattern matcher |
| Interpreter | A generalization of script interpreters |
| Logger | A logger |
| Progress | A progress reporter |
| Recipe | A facility for providing reproducible recipes |
| RelativeProgress | A progress reporter counting progress in relative units |
| Timer | A timer (stop watch) |
| Value | Encapsulates a value (preferably a plain data type) in an object |