3. A Generated Code Interpreter

In this chapter we start afresh on a second model run-time system in sub-project rt2. We use the knowledge gained writing the code in sub-project rt1 to bank some architectural concepts (that will hopefully prove enduring) but take a different approach to implementation.

• 3.1. Introduction
  • 3.1.1. Concepts Banked
  • 3.1.2. Concepts to be Explored
• 3.2. An Interpreter for CPython Byte Code
  • 3.2.1. PyObject as an Interface
  • 3.2.2. Basic types int, float and str
  • 3.2.3. Objects for bytes and tuple
  • 3.2.4. Implementing dict
  • 3.2.5. A Python exception as a Java Throwable
  • 3.2.6. Runtime Support: Py
  • 3.2.7. Implementing code
  • 3.2.8. Implementing frame
  • 3.2.9. The frame as an Interpreter
  • 3.2.10. Program Examples
    • Help from the CPython Compiler
    • Some Homemade Magic
• 3.3. Type and Arithmetic Operations
  • 3.3.1. Representing a Python Class
  • 3.3.2. A Unary Operation UNARY_NEGATIVE
  • 3.3.3. A Binary Operation BINARY_ADD
  • 3.3.4. How we Fill the Slots
• 3.4. Sequences and Indexing
  • 3.4.1. Tuple Creation and Indexing
  • 3.4.2. List Creation and Indexing
• 3.5. Built-in Inheritance
  • 3.5.1. The Example of bool
  • 3.5.2. Inheritance will not be Free
    • Python gives us a Break
    • Choices in the Implementation of Inheritance
  • 3.5.3. A Simplified MRO
  • 3.5.4. Hints from the C Implementation
  • 3.5.5. A bool Implementation
  • 3.5.6. Exceptions and Inheritance
• 3.6. Comparison and Loops
  • 3.6.1. Motivating Example
  • 3.6.2. Branch instructions
  • 3.6.3. Rich Comparison
• 3.7. Refactoring for evo3
  • 3.7.1. Static Factory Methods in Py
  • 3.7.2. Some Re-naming
  • 3.7.3. Re-working PyType
    • Untangling the Type Initialisation
    • Flattening the Slot-function Table
    • Manipulation of Slots and PyType.flags
    • Inheritance of Slot Functions
  • 3.7.4. Lightweight EmptyException
  • 3.7.5. Type Cast in the Method Handle
• 3.8. Function Definition and Call
  • 3.8.1. Calling a Function
    • The “Simple” Call
    • The “Classic” Call
    • The Simple (“Vector”) Call
  • 3.8.2. Defining a Function in Java
    • A Specialised Callable
    • A Function in a Module
    • CPython PyMethodDef and PyCFunctionObject
    • Java MethodDef and PyJavaFunction
  • 3.8.3. Defining a Function in Python
    • Definition site
    • Classic call site
    • Processing a classic call
    • Processing a vector call
    • Possibilities for Optimisation
      • Fast path in simple cases
      • Possibility of using MethodHandle
• 3.9. Refactoring for evo4
  • 3.9.1. Another Re-work of Core Types
    • Motivation
    • Scope
  • 3.9.2. Slot Functions
    • A Java Approach the Slot Table
    • Defining Comparison Operations
    • Defining __getitem__ and similar
  • 3.9.3. Java Signatures of Slots
• 3.10. Access to Attributes
  • 3.10.1. Exploration
    • Slots for Attribute Access
      • Candidate getAttr
    • A Custom Class with Attribute Access
    • The Instance Dictionary
      • Interface PyObjectDict
      • Read-only Dictionary (PyType)
  • 3.10.2. The Mechanism of Attribute Access
    • __getattribute__ and __getattr__
      • A Java Approach
    • Descriptors in Concept
    • Implementing object.__getattribute__
    • Implementing object.__setattr__
    • Implementing object.__delattr__
    • Implementing type.__getattribute__
    • Implementing type.__setattr__
    • Implementing type.__delattr__
  • 3.10.3. A Glance up the Mountain
• 3.11. Attributes Defined in Java
  • 3.11.1. Access to Attributes: A Trivial Case
    • Motivating Example
    • Creating an Instance with __new__
  • 3.11.2. Class and Instance Improvements
    • Orientation
    • __call__ in PyType
    • Slots tp_new and tp_init
    • __new__ in PyLong
    • __new__ in PyType (Provisional)
  • 3.11.3. Descriptors in Class Creation (Java)
  • 3.11.4. Integrating the Parts
    • Defining a Simple Class
• 3.12. Attributes Defined in Python
  • 3.12.1. Access to Attributes: A Trivial Case
    • Motivating Example
    • Creating an Instance with __new__
  • 3.12.2. Class and Instance Improvements
    • Orientation
    • __call__ in PyType
    • Slots tp_new and tp_init
    • __new__ in PyType (Provisional)
    • The Instance Dictionary
      • Support in PyObject
      • Read-only Dictionary (PyType)
  • 3.12.3. Descriptors in Class Creation (Python)
  • 3.12.4. Integrating the Parts
    • Defining a Simple Class
    • A First Approximation to __build_class__