[Python-checkins] r64015 - in python/trunk: Doc/library/_ast.rst Doc/library/language.rst Lib/test/test_ast.py
georg.brandl
python-checkins at python.org
Sat Jun 7 18:04:02 CEST 2008
Author: georg.brandl
Date: Sat Jun 7 18:04:01 2008
New Revision: 64015
Log:
Revert unwanted changes.
Added:
python/trunk/Doc/library/_ast.rst
Modified:
python/trunk/Doc/library/language.rst
python/trunk/Lib/test/test_ast.py
Added: python/trunk/Doc/library/_ast.rst
==============================================================================
--- (empty file)
+++ python/trunk/Doc/library/_ast.rst Sat Jun 7 18:04:01 2008
@@ -0,0 +1,85 @@
+.. _ast:
+
+Abstract Syntax Trees
+=====================
+
+.. module:: _ast
+ :synopsis: Abstract Syntax Tree classes.
+
+.. sectionauthor:: Martin v. Löwis <martin at v.loewis.de>
+
+
+.. versionadded:: 2.5
+
+The ``_ast`` module helps Python applications to process trees of the Python
+abstract syntax grammar. The abstract syntax itself might change with each
+Python release; this module helps to find out programmatically what the current
+grammar looks like.
+
+An abstract syntax tree can be generated by passing :data:`_ast.PyCF_ONLY_AST`
+as a flag to the :func:`compile` builtin function. The result will be a tree of
+objects whose classes all inherit from :class:`_ast.AST`.
+
+A modified abstract syntax tree can be compiled into a Python code object using
+the built-in :func:`compile` function.
+
+The actual classes are derived from the ``Parser/Python.asdl`` file, which is
+reproduced below. There is one class defined for each left-hand side symbol in
+the abstract grammar (for example, ``_ast.stmt`` or ``_ast.expr``). In addition,
+there is one class defined for each constructor on the right-hand side; these
+classes inherit from the classes for the left-hand side trees. For example,
+``_ast.BinOp`` inherits from ``_ast.expr``. For production rules with
+alternatives (aka "sums"), the left-hand side class is abstract: only instances
+of specific constructor nodes are ever created.
+
+Each concrete class has an attribute ``_fields`` which gives the names of all
+child nodes.
+
+Each instance of a concrete class has one attribute for each child node, of the
+type as defined in the grammar. For example, ``_ast.BinOp`` instances have an
+attribute ``left`` of type ``_ast.expr``. Instances of ``_ast.expr`` and
+``_ast.stmt`` subclasses also have lineno and col_offset attributes. The lineno
+is the line number of source text (1 indexed so the first line is line 1) and
+the col_offset is the utf8 byte offset of the first token that generated the
+node. The utf8 offset is recorded because the parser uses utf8 internally.
+
+If these attributes are marked as optional in the grammar (using a question
+mark), the value might be ``None``. If the attributes can have zero-or-more
+values (marked with an asterisk), the values are represented as Python lists.
+All possible attributes must be present and have valid values when compiling an
+AST with :func:`compile`.
+
+The constructor of a class ``_ast.T`` parses their arguments as follows:
+
+* If there are positional arguments, there must be as many as there are items in
+ ``T._fields``; they will be assigned as attributes of these names.
+* If there are keyword arguments, they will set the attributes of the same names
+ to the given values.
+
+For example, to create and populate a ``UnaryOp`` node, you could use ::
+
+ node = _ast.UnaryOp()
+ node.op = _ast.USub()
+ node.operand = _ast.Num()
+ node.operand.n = 5
+ node.operand.lineno = 0
+ node.operand.col_offset = 0
+ node.lineno = 0
+ node.col_offset = 0
+
+or the more compact ::
+
+ node = _ast.UnaryOp(_ast.USub(), _ast.Num(5, lineno=0, col_offset=0),
+ lineno=0, col_offset=0)
+
+
+
+Abstract Grammar
+----------------
+
+The module defines a string constant ``__version__`` which is the decimal
+subversion revision number of the file shown below.
+
+The abstract grammar is currently defined as follows:
+
+.. literalinclude:: ../../Parser/Python.asdl
Modified: python/trunk/Doc/library/language.rst
==============================================================================
--- python/trunk/Doc/library/language.rst (original)
+++ python/trunk/Doc/library/language.rst Sat Jun 7 18:04:01 2008
@@ -15,7 +15,7 @@
.. toctree::
parser.rst
- ast.rst
+ _ast.rst
symbol.rst
token.rst
keyword.rst
Modified: python/trunk/Lib/test/test_ast.py
==============================================================================
--- python/trunk/Lib/test/test_ast.py (original)
+++ python/trunk/Lib/test/test_ast.py Sat Jun 7 18:04:01 2008
@@ -1,6 +1,6 @@
import sys, itertools, unittest
from test import test_support
-import ast
+import _ast
def to_tuple(t):
if t is None or isinstance(t, (basestring, int, long, complex)):
@@ -123,9 +123,9 @@
class AST_Tests(unittest.TestCase):
def _assert_order(self, ast_node, parent_pos):
- if not isinstance(ast_node, ast.AST) or ast_node._fields is None:
+ if not isinstance(ast_node, _ast.AST) or ast_node._fields is None:
return
- if isinstance(ast_node, (ast.expr, ast.stmt, ast.excepthandler)):
+ if isinstance(ast_node, (_ast.expr, _ast.stmt, _ast.excepthandler)):
node_pos = (ast_node.lineno, ast_node.col_offset)
self.assert_(node_pos >= parent_pos)
parent_pos = (ast_node.lineno, ast_node.col_offset)
@@ -142,29 +142,29 @@
(single_tests, single_results, "single"),
(eval_tests, eval_results, "eval")):
for i, o in itertools.izip(input, output):
- ast_tree = compile(i, "?", kind, ast.PyCF_ONLY_AST)
+ ast_tree = compile(i, "?", kind, _ast.PyCF_ONLY_AST)
self.assertEquals(to_tuple(ast_tree), o)
self._assert_order(ast_tree, (0, 0))
def test_nodeclasses(self):
- x = ast.BinOp(1, 2, 3, lineno=0)
+ x = _ast.BinOp(1, 2, 3, lineno=0)
self.assertEquals(x.left, 1)
self.assertEquals(x.op, 2)
self.assertEquals(x.right, 3)
self.assertEquals(x.lineno, 0)
# node raises exception when not given enough arguments
- self.assertRaises(TypeError, ast.BinOp, 1, 2)
+ self.assertRaises(TypeError, _ast.BinOp, 1, 2)
# can set attributes through kwargs too
- x = ast.BinOp(left=1, op=2, right=3, lineno=0)
+ x = _ast.BinOp(left=1, op=2, right=3, lineno=0)
self.assertEquals(x.left, 1)
self.assertEquals(x.op, 2)
self.assertEquals(x.right, 3)
self.assertEquals(x.lineno, 0)
# this used to fail because Sub._fields was None
- x = ast.Sub()
+ x = _ast.Sub()
def test_pickling(self):
import pickle
@@ -181,99 +181,8 @@
ast2 = mod.loads(mod.dumps(ast, protocol))
self.assertEquals(to_tuple(ast2), to_tuple(ast))
-
-class ASTHelpers_Test(unittest.TestCase):
-
- def test_parse(self):
- a = ast.parse('foo(1 + 1)')
- b = compile('foo(1 + 1)', '<unknown>', 'exec', ast.PyCF_ONLY_AST)
- self.assertEqual(ast.dump(a), ast.dump(b))
-
- def test_dump(self):
- node = ast.parse('spam(eggs, "and cheese")')
- self.assertEqual(ast.dump(node),
- "Module(body=[Expr(value=Call(func=Name(id='spam', ctx=Load()), "
- "args=[Name(id='eggs', ctx=Load()), Str(s='and cheese')], "
- "keywords=[], starargs=None, kwargs=None))])"
- )
- self.assertEqual(ast.dump(node, annotate_fields=False),
- "Module([Expr(Call(Name('spam', Load()), [Name('eggs', Load()), "
- "Str('and cheese')], [], None, None))])"
- )
- self.assertEqual(ast.dump(node, include_attributes=True),
- "Module(body=[Expr(value=Call(func=Name(id='spam', ctx=Load(), "
- "lineno=1, col_offset=0), args=[Name(id='eggs', ctx=Load(), "
- "lineno=1, col_offset=5), Str(s='and cheese', lineno=1, "
- "col_offset=11)], keywords=[], starargs=None, kwargs=None, "
- "lineno=1, col_offset=0), lineno=1, col_offset=0)])"
- )
-
- def test_copy_location(self):
- src = ast.parse('1 + 1', mode='eval')
- src.body.right = ast.copy_location(ast.Num(2), src.body.right)
- self.assertEqual(ast.dump(src, include_attributes=True),
- 'Expression(body=BinOp(left=Num(n=1, lineno=1, col_offset=0), '
- 'op=Add(), right=Num(n=2, lineno=1, col_offset=4), lineno=1, '
- 'col_offset=0))'
- )
-
- def test_fix_missing_locations(self):
- src = ast.parse('write("spam")')
- src.body.append(ast.Expr(ast.Call(ast.Name('spam', ast.Load()),
- [ast.Str('eggs')], [], None, None)))
- self.assertEqual(src, ast.fix_missing_locations(src))
- self.assertEqual(ast.dump(src, include_attributes=True),
- "Module(body=[Expr(value=Call(func=Name(id='write', ctx=Load(), "
- "lineno=1, col_offset=0), args=[Str(s='spam', lineno=1, "
- "col_offset=6)], keywords=[], starargs=None, kwargs=None, "
- "lineno=1, col_offset=0), lineno=1, col_offset=0), "
- "Expr(value=Call(func=Name(id='spam', ctx=Load(), lineno=1, "
- "col_offset=0), args=[Str(s='eggs', lineno=1, col_offset=0)], "
- "keywords=[], starargs=None, kwargs=None, lineno=1, "
- "col_offset=0), lineno=1, col_offset=0)])"
- )
-
- def test_increment_lineno(self):
- src = ast.parse('1 + 1', mode='eval')
- self.assertEqual(ast.increment_lineno(src, n=3), src)
- self.assertEqual(ast.dump(src, include_attributes=True),
- 'Expression(body=BinOp(left=Num(n=1, lineno=4, col_offset=0), '
- 'op=Add(), right=Num(n=1, lineno=4, col_offset=4), lineno=4, '
- 'col_offset=0))'
- )
-
- def test_iter_fields(self):
- node = ast.parse('foo()', mode='eval')
- d = dict(ast.iter_fields(node.body))
- self.assertEqual(d.pop('func').id, 'foo')
- self.assertEqual(d, {'keywords': [], 'kwargs': None,
- 'args': [], 'starargs': None})
-
- def test_iter_child_nodes(self):
- node = ast.parse("spam(23, 42, eggs='leek')", mode='eval')
- self.assertEqual(len(list(ast.iter_child_nodes(node.body))), 4)
- iterator = ast.iter_child_nodes(node.body)
- self.assertEqual(next(iterator).id, 'spam')
- self.assertEqual(next(iterator).n, 23)
- self.assertEqual(next(iterator).n, 42)
- self.assertEqual(ast.dump(next(iterator)),
- "keyword(arg='eggs', value=Str(s='leek'))"
- )
-
- def test_get_docstring(self):
- node = ast.parse('def foo():\n """line one\n line two"""')
- self.assertEqual(ast.get_docstring(node.body[0]),
- 'line one\n line two')
-
- def test_literal_eval(self):
- self.assertEqual(ast.literal_eval('[1, 2, 3]'), [1, 2, 3])
- self.assertEqual(ast.literal_eval('{"foo": 42}'), {"foo": 42})
- self.assertEqual(ast.literal_eval('(True, False, None)'), (True, False, None))
- self.assertRaises(ValueError, ast.literal_eval, 'foo()')
-
-
def test_main():
- test_support.run_unittest(AST_Tests, ASTHelpers_Test)
+ test_support.run_unittest(AST_Tests)
def main():
if __name__ != '__main__':
More information about the Python-checkins
mailing list