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**Objectives**

Research and validate the flexibility of PyPy by building key middleware
features into the language itself.

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**Description of work**

**Task 1**

Analyze and implement security models at the language level.  Implement
the "RExec" restricted execution model.  (It was removed from the official
Python implementation because it was too hard to maintain.)

**Task 2**

Analyze and implement distributed execution models at the language level.
Implement network-transparent execution of Python programs.  (Typical
libraries require programs to be aware of the remote execution model.)

**Task 3**

Analyze and implement persistence at the language level.  Implement an
orthogonally persistent object space for Python programs.  (Persistence
is never fully orthogonal without advanced language support.)

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**Deliverables**

- D12.1 A PyPy version which supports secure restricted execution of arbitrary Python programs

- D12.2 A PyPy version which supports distributed execution of arbitrary Python programs

- D12.3 A PyPy version which supports persistent execution of arbitrary Python programs

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**Milestones and Expected Result**

- M4 Validation of the flexibility of PyPy with respect to key middleware requirements

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