On Jul 10, 12:40 pm, eliben <[EMAIL PROTECTED]> wrote: > Hello, > > I'm building a parser in Python, and while pondering on the design of > my ASTs had the idea to see what Python uses. I quickly got to the > compiler.ast module, and understood it's automatically generated. So I > went to the source, ast.txt and tools/compiler/astgen.py, where I was > this unexpected message: > > """Generate ast module from specification > > This script generates the ast module from a simple specification, > which makes it easy to accomodate changes in the grammar. This > approach would be quite reasonable if the grammar changed often. > Instead, it is rather complex to generate the appropriate code. And > the Node interface has changed more often than the grammar. > """ > > Now, to me the design of the AST in Python looks quite elegant, > especially from the point of view of the AST's user (using Visitors to > walk the AST). And astgen.py looks like a nice approach to generate > tons of boilerplate code. > So, my questions: > 1) Is the compiler.ast module really employed during the compilation > of Python into .pyc files ?
No, the comment refers to the builtin _ast module. The compiler package is a compiler for Python written in Python. > 2) What is the meaning of the comment in astgen.py ? Are the Python > maintainers unhappy with the design of the AST ?3 Node, I think, is talking about a node in the parse tree. (AST is generated from another parse tree.) See PEP 339 for details. > 3) What other approach would be recommended to generate a very > detailed AST hierarchy, if the one in astgen.py is dissapointing ? astgen.py contains things that are specific to writing Python's AST C code. Have a look at spark.py in the Parser dir. It is what astgen.py is based on. > > Thanks in advance > Eli -- http://mail.python.org/mailman/listinfo/python-list
