Python ast.Load() Examples

def visit_Expr(self, node):
        newnode = ast.copy_location(ast.Expr(
                value = ast.Call(
                    func = ast.Attribute(
                        value = ast.Name(id='__swirlypy_recorder__',
                                    ctx=ast.Load()),
                                    attr="record",
                                    ctx=ast.Load()),
                                    args=[node.value],
                                    keywords=[],
                                    starargs=None,
                                    kwargs=None
                        )
                    ),
                node)
        ast.fix_missing_locations(newnode)
        return newnode 

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 __init__(
            self,
            keys: t.List[ast.expr],
            values: t.List[ast.expr],
            ctx: t.Union[ast.Store, ast.Load],
            lineno=None,
            col_offset=None,
    ):
        super().__init__()
        self.keys = keys
        self.values = values
        self.ctx = ctx
        if lineno:
            self.lineno = lineno
        if col_offset:
            self.col_offset = col_offset 

def visit_Attribute(self, node, **kwargs):
        attr = node.attr
        value = node.value

        ctx = node.ctx
        if isinstance(ctx, ast.Load):
            # resolve the value
            resolved = self.visit(value).value
            try:
                v = getattr(resolved, attr)
                name = self.env.add_tmp(v)
                return self.term_type(name, self.env)
            except AttributeError:
                # something like datetime.datetime where scope is overridden
                if isinstance(value, ast.Name) and value.id == attr:
                    return resolved

        raise ValueError("Invalid Attribute context {name}"
                         .format(name=ctx.__name__)) 

def NAME(self, node):
        """
        Handle occurrence of Name (which can be a load/store/delete access.)
        """
        # Locate the name in locals / function / globals scopes.
        if isinstance(node.ctx, (ast.Load, ast.AugLoad)):
            self.handleNodeLoad(node)
            if (node.id == 'locals' and isinstance(self.scope, FunctionScope)
                    and isinstance(node.parent, ast.Call)):
                # we are doing locals() call in current scope
                self.scope.usesLocals = True
        elif isinstance(node.ctx, (ast.Store, ast.AugStore)):
            self.handleNodeStore(node)
        elif isinstance(node.ctx, ast.Del):
            self.handleNodeDelete(node)
        else:
            # must be a Param context -- this only happens for names in function
            # arguments, but these aren't dispatched through here
            raise RuntimeError("Got impossible expression context: %r" % (node.ctx,)) 

def visit_Attribute(self, node, **kwargs):
        attr = node.attr
        value = node.value

        ctx = node.ctx.__class__
        if ctx == ast.Load:
            # resolve the value
            resolved = self.visit(value)

            # try to get the value to see if we are another expression
            try:
                resolved = resolved.value
            except (AttributeError):
                pass

            try:
                return self.term_type(getattr(resolved, attr), self.env)
            except AttributeError:

                # something like datetime.datetime where scope is overriden
                if isinstance(value, ast.Name) and value.id == attr:
                    return resolved

        raise ValueError("Invalid Attribute context {0}".format(ctx.__name__)) 

def visit_Attribute(self, node, **kwargs):
        attr = node.attr
        value = node.value

        ctx = node.ctx
        if isinstance(ctx, ast.Load):
            # resolve the value
            resolved = self.visit(value).value
            try:
                v = getattr(resolved, attr)
                name = self.env.add_tmp(v)
                return self.term_type(name, self.env)
            except AttributeError:
                # something like datetime.datetime where scope is overridden
                if isinstance(value, ast.Name) and value.id == attr:
                    return resolved

        raise ValueError("Invalid Attribute context {0}".format(ctx.__name__)) 

def make_annotation(node=None, buffer='outside', content=None, cell_type='code', lineno=None):
    """Return a ast.Expr that looks like

    ```
    __cell__('make-cell', [content, buffer, cell_type])
    ```

    """
    content = astor.to_source(node).strip() if node else content
    lineno = str(node.lineno) if hasattr(node, 'lineno') else str(-1) if not lineno else str(lineno)
    call = ast.Call(
        func=ast.Name(id='__cell__', ctx=ast.Load()),
        args=[
            ast.Str(s=content),
            ast.Str(s=f'{buffer}'),
            ast.Str(s=cell_type),
            ast.Str(s=lineno),
        ],
        keywords=[]
    )
    return ast.Expr(call) 

def visit_Return(self, return_):
        """Convert returns into assignment/exception pairs

        Since the body of this function will be in the global namespace we
        can't have any returns. An acceptable alternative is to set a variable
        called 'RETURN' and then immediately raise an exception.

        >>> self = NamespacePromoter(buffer='foo')
        >>> code = '''
        ...
        ... return 5
        ...
        ... '''
        >>> tree = ast.parse(code)
        >>> return_, = tree.body

        """
        nodes = [
            ast.Assign(targets=[ast.Name(id='RETURN', ctx=ast.Store())], value=return_.value, lineno=return_.lineno),
            ast.Raise(exc=ast.Call(func=ast.Name(id='Exception', ctx=ast.Load()), args=[ast.Str(s='return')], keywords=[]), cause=None),
        ]
        return nodes 

def visit_Attribute(self, node, **kwargs):
        attr = node.attr
        value = node.value

        ctx = node.ctx.__class__
        if ctx == ast.Load:
            # resolve the value
            resolved = self.visit(value)

            # try to get the value to see if we are another expression
            try:
                resolved = resolved.value
            except (AttributeError):
                pass

            try:
                return self.term_type(getattr(resolved, attr), self.env)
            except AttributeError:

                # something like datetime.datetime where scope is overridden
                if isinstance(value, ast.Name) and value.id == attr:
                    return resolved

        raise ValueError("Invalid Attribute context {name}"
                         .format(name=ctx.__name__)) 

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 visit(self, node) -> Any:
        if isinstance(node, ast.Name):
            if isinstance(node.ctx, ast.Load):
                self.loaded.add(node.id)
            elif isinstance(node.ctx, ast.Store):
                self.stored.add(node.id)
        elif isinstance(node, ast.Return):
            self.has_return = True
        # We must keep track of importer name in order to avoid considering as variable
        # names:
        elif isinstance(node, ast.Import):
            self.imported.update([ n.name for n in node.names])
        elif isinstance(node, ast.ImportFrom):
            self.imported.update([ n.name for n in node.names])

        self.generic_visit(node) 

def test_noflattening(self):
        'Tests where nothing should be flattened'
        corresp = [(["a + b", "b + a"],
                   ast.BinOp(ast.Name('a', ast.Load()),
                             ast.Add(),
                             ast.Name('b', ast.Load()))),
                   (["c*d", "d*c"],
                    ast.BinOp(ast.Name('c', ast.Load()),
                              ast.Mult(),
                              ast.Name('d', ast.Load()))),
                   (["a + c*d", "d*c + a"],
                    ast.BinOp(ast.Name('a', ast.Load()), ast.Add(),
                              ast.BinOp(ast.Name('c', ast.Load()), ast.Mult(),
                                        ast.Name('d', ast.Load()))))]
        for refstring, result in corresp:
            self.generic_flattening(refstring, result) 

def visit_Rep0N(self, node: parsing.Rep0N) -> [ast.stmt]:
        """Generates python code for a clause repeated 0 or more times.

        #If all clauses can be inlined
        while clause:
            pass

        while True:
            <code for the clause>
        """
        cl_ast = self.visit(node.pt)
        if isinstance(cl_ast, ast.expr):
            return [ast.While(cl_ast, [ast.Pass()], [])]
        self.in_loop += 1
        clause = self._clause(self.visit(node.pt))
        self.in_loop -= 1
        return [ast.While(ast.Name('True', ast.Load()), clause, [])] 

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_attributes(self):
        # assert True, "bad"
        assert0 = ast.Assert()
        self.assertFalse(hasattr(assert0, 'lineno'))
        self.assertFalse(hasattr(assert0, 'col_offset'))
        assert1 = ast.Assert(ast.Name('True', ast.Load()), ast.Str('bad'))
        self.assertFalse(hasattr(assert1, 'lineno'))
        self.assertFalse(hasattr(assert1, 'col_offset'))
        try:
            tmp=assert1.lineno
        except Exception as e:
            self.assertTrue(isinstance(e,AttributeError))
        try:
            tmp=assert1.col_offset
        except Exception as e:
            self.assertTrue(isinstance(e,AttributeError))
        assert2 = ast.Assert(ast.Name('True', ast.Load()), ast.Str('bad'),2,3)
        self.assertEqual(assert2.lineno,2)
        self.assertEqual(assert2.col_offset,3) 

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 visit_Attribute(self, node, **kwargs):
        attr = node.attr
        value = node.value

        ctx = node.ctx.__class__
        if ctx == ast.Load:
            # resolve the value
            resolved = self.visit(value)

            # try to get the value to see if we are another expression
            try:
                resolved = resolved.value
            except (AttributeError):
                pass

            try:
                return self.term_type(getattr(resolved, attr), self.env)
            except AttributeError:

                # something like datetime.datetime where scope is overridden
                if isinstance(value, ast.Name) and value.id == attr:
                    return resolved

        raise ValueError("Invalid Attribute context {name}"
                         .format(name=ctx.__name__)) 

def visit_Attribute(self, node, **kwargs):
        attr = node.attr
        value = node.value

        ctx = node.ctx
        if isinstance(ctx, ast.Load):
            # resolve the value
            resolved = self.visit(value).value
            try:
                v = getattr(resolved, attr)
                name = self.env.add_tmp(v)
                return self.term_type(name, self.env)
            except AttributeError:
                # something like datetime.datetime where scope is overridden
                if isinstance(value, ast.Name) and value.id == attr:
                    return resolved

        raise ValueError("Invalid Attribute context {name}"
                         .format(name=ctx.__name__)) 

def pop_format_context(self, expl_expr):
        """Format the %-formatted string with current format context.

        The expl_expr should be an ast.Str instance constructed from
        the %-placeholders created by .explanation_param().  This will
        add the required code to format said string to .expl_stmts and
        return the ast.Name instance of the formatted string.

        """
        current = self.stack.pop()
        if self.stack:
            self.explanation_specifiers = self.stack[-1]
        keys = [ast.Str(key) for key in current.keys()]
        format_dict = ast.Dict(keys, list(current.values()))
        form = ast.BinOp(expl_expr, ast.Mod(), format_dict)
        name = "@py_format" + str(next(self.variable_counter))
        if self.enable_assertion_pass_hook:
            self.format_variables.append(name)
        self.expl_stmts.append(ast.Assign([ast.Name(name, ast.Store())], form))
        return ast.Name(name, ast.Load()) 

def __exit_scope(self) -> ast.stmt:
        """Create the appropriate scope exiting statement.

        The documentation only shows one level and always uses
        'return False' in examples.

        'raise AltFalse()' within a try.
        'break' within a loop.
        'return False' otherwise.
        """
        if self.in_optional:
            return ast.Pass()
        if self.in_try:
            return ast.Raise(
                ast.Call(ast.Name('AltFalse', ast.Load()), [], [], None, None),
                None)
        if self.in_loop:
            return ast.Break()
        return ast.Return(ast.Name('False', ast.Load()))

    #TODO(bps): find a better name to describe what this does 

def visit_Hook(self, node: parsing.Hook) -> ast.expr:
        """Generates python code calling a hook.

        self.evalHook('hookname', self.ruleNodes[-1])
        """
        return ast.Call(
            ast.Attribute(
                ast.Name('self', ast.Load()), 'evalHook', ast.Load()),
            [
                ast.Str(node.name),
                ast.Subscript(
                    ast.Attribute(
                        ast.Name('self', ast.Load()), 'ruleNodes', ast.Load()),
                    ast.Index(ast.UnaryOp(ast.USub(), ast.Num(1))),
                    ast.Load())],
            [],
            None,
            None) 

def pop_format_context(self, expl_expr):
        """Format the %-formatted string with current format context.

        The expl_expr should be an ast.Str instance constructed from
        the %-placeholders created by .explanation_param().  This will
        add the required code to format said string to .expl_stmts and
        return the ast.Name instance of the formatted string.

        """
        current = self.stack.pop()
        if self.stack:
            self.explanation_specifiers = self.stack[-1]
        keys = [ast.Str(key) for key in current.keys()]
        format_dict = ast.Dict(keys, list(current.values()))
        form = ast.BinOp(expl_expr, ast.Mod(), format_dict)
        name = "@py_format" + str(next(self.variable_counter))
        if self.enable_assertion_pass_hook:
            self.format_variables.append(name)
        self.expl_stmts.append(ast.Assign([ast.Name(name, ast.Store())], form))
        return ast.Name(name, ast.Load()) 

def visit_BinOp(self, node):
        'Replace bitwise operation with function call'
        self.generic_visit(node)
        if isinstance(node.op, ast.BitAnd):
            return ast.Call(ast.Name('mand', ast.Load()),
                            [node.left, node.right], [], None, None)
        if isinstance(node.op, ast.BitOr):
            return ast.Call(ast.Name('mor', ast.Load()),
                            [node.left, node.right], [], None, None)
        if isinstance(node.op, ast.BitXor):
            return ast.Call(ast.Name('mxor', ast.Load()),
                            [node.left, node.right], [], None, None)
        if isinstance(node.op, ast.LShift):
            return ast.Call(ast.Name('mlshift', ast.Load()),
                            [node.left, node.right], [], None, None)
        if isinstance(node.op, ast.RShift):
            return ast.Call(ast.Name('mrshift', ast.Load()),
                            [node.left, node.right], [], None, None)
        return node 

def test_invalid_identitifer(self):
        m = ast.Module([ast.Expr(ast.Name(u"x", ast.Load()))])
        ast.fix_missing_locations(m)
        with self.assertRaises(TypeError) as cm:
            compile(m, "<test>", "exec")
        self.assertIn("identifier must be of type str", str(cm.exception)) 

def visit_Name(self, node: ast.Name) -> None:
        if self._is_six(node, SIX_SIMPLE_ATTRS):
            self.six_simple[_ast_to_offset(node)] = node

        if self._scope_stack:
            if isinstance(node.ctx, ast.Load):
                self._scope_stack[-1].reads.add(node.id)
            elif isinstance(node.ctx, (ast.Store, ast.Del)):
                self._scope_stack[-1].writes.add(node.id)
            else:
                raise AssertionError(node)

        self.generic_visit(node) 

def _make_fn(name, chain_fn, args, defaults):
    args_with_self = ['_self'] + list(args)
    arguments = [_ast.Name(id=arg, ctx=_ast.Load()) for arg in args_with_self]
    defs = [_ast.Name(id='_def{0}'.format(idx), ctx=_ast.Load()) for idx, _ in enumerate(defaults)]
    if _PY2:
        parameters = _ast.arguments(args=[_ast.Name(id=arg, ctx=_ast.Param()) for arg in args_with_self],
                                    defaults=defs)
    else:
        parameters = _ast.arguments(args=[_ast.arg(arg=arg) for arg in args_with_self],
                                    kwonlyargs=[],
                                    defaults=defs,
                                    kw_defaults=[])
    module_node = _ast.Module(body=[_ast.FunctionDef(name=name,
                                                     args=parameters,
                                                     body=[_ast.Return(value=_ast.Call(func=_ast.Name(id='_chain', ctx=_ast.Load()),
                                                                                       args=arguments,
                                                                                       keywords=[]))],
                                                     decorator_list=[])])
    module_node = _ast.fix_missing_locations(module_node)

    # compile the ast
    code = compile(module_node, '<string>', 'exec')

    # and eval it in the right context
    globals_ = {'_chain': chain_fn}
    locals_ = dict(('_def{0}'.format(idx), value) for idx, value in enumerate(defaults))
    eval(code, globals_, locals_)

    # extract our function from the newly created module
    return locals_[name]


########################################################################
# Produce a docstring for the class. 

def visit_For(self, loop):
        """Pure syntax rewrite of a for loop

        Unroll only the first iteration through the loop.

        >>> self = FirstPassForSimple('foo')

        """
        # loop = self.generic_visit(loop)

        # iter(loop.iter)
        iter_call = ast.Call(
            func=ast.Name(id='iter', ctx=ast.Load()),
            args=[ast.Name(id=loop.iter, ctx=ast.Load())],
            keywords=[]
        )

        # i = next(iter(loop.iter))
        get_first = ast.Assign(
            targets=[loop.target],
            value=ast.Call(
                func=ast.Name(id='next', ctx=ast.Load()),
                args=[iter_call],
                keywords=[]
            )
        )
        content = f'`for {astor.to_source(loop.target).strip()} in {astor.to_source(loop.iter).strip()} ...`'
        nodes = []
        nodes.append(make_annotation(buffer=self.buffer, content=content, cell_type='2', lineno=loop.lineno))
        nodes.append(ast.Expr(loop.iter))
        nodes.append(get_first)
        nodes.extend(loop.body)
        return nodes 

def visit_expr(self, node):
        # type: (ast.expr) -> ast.Call
        """
        each expression e gets wrapped like this:
            _treetrace_hidden_after_expr(_treetrace_hidden_before_expr(_tree_index), e)

        where the _treetrace_* functions are the corresponding methods with the
        TreeTracerBase and traced_file arguments already filled in (see _trace_methods_dict)
        """

        before_marker = ast.Call(
            func=ast.Name(id=self.before_name,
                          ctx=ast.Load()),
            args=[ast.Num(node._tree_index)],
            keywords=[],
        )

        ast.copy_location(before_marker, node)
        
        if isinstance(node, FormattedValue):
            arg = node
        else:
            arg = super(NodeVisitor, self).generic_visit(node)

        after_marker = ast.Call(
            func=ast.Name(id=self.after_name,
                          ctx=ast.Load()),
            args=[
                before_marker,
                arg,
            ],
            keywords=[],
        )
        ast.copy_location(after_marker, node)
        ast.fix_missing_locations(after_marker)

        return after_marker 

def test_invalid_identitifer(self):
        m = ast.Module([ast.Expr(ast.Name(u"x", ast.Load()))])
        ast.fix_missing_locations(m)
        with self.assertRaises(TypeError) as cm:
            compile(m, "<test>", "exec")
        self.assertIn("identifier must be of type str", str(cm.exception))