\item The design of the bytecode compiler has changed a great deal, no

longer generating bytecode by traversing the parse tree. Instead

the parse tree is converted to an abstract syntax tree (or AST), and it is

the abstract syntax tree that's traversed to produce the bytecode.

No documentation has been written for the AST code yet. To start

learning about it, read the definition of the various AST nodes in

\file{Parser/Python.asdl}. A Python script reads this file and

generates a set of C structure definitions in

\file{Include/Python-ast.h}. The \cfunction{PyParser_ASTFromString()}

and \cfunction{PyParser_ASTFromFile()}, defined in

\file{Include/pythonrun.h}, take Python source as input and return the

root of an AST representing the contents. This AST can then be turned

into a code object by \cfunction{PyAST_Compile()}. For more

information, read the source code, and then ask questions on

python-dev.

The AST code was developed under Jeremy Hylton's management, and

implemented by (in alphabetical order) Brett Cannon, Nick Coghlan,

Grant Edwards, John Ehresman, Kurt Kaiser, Neal Norwitz, Tim Peters,

Armin Rigo, and Neil Schemenauer, plus the participants in a number of

AST sprints at conferences such as PyCon.