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#############################################################################
##
## Copyright (C) 2020 The Qt Company Ltd.
## Contact: https://www.qt.io/licensing/
##
## This file is part of the Qt for Python project.
##
## $QT_BEGIN_LICENSE:LGPL$
## Commercial License Usage
## Licensees holding valid commercial Qt licenses may use this file in
## accordance with the commercial license agreement provided with the
## Software or, alternatively, in accordance with the terms contained in
## a written agreement between you and The Qt Company. For licensing terms
## and conditions see https://www.qt.io/terms-conditions. For further
## information use the contact form at https://www.qt.io/contact-us.
##
## GNU Lesser General Public License Usage
## Alternatively, this file may be used under the terms of the GNU Lesser
## General Public License version 3 as published by the Free Software
## Foundation and appearing in the file LICENSE.LGPL3 included in the
## packaging of this file. Please review the following information to
## ensure the GNU Lesser General Public License version 3 requirements
## will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
##
## GNU General Public License Usage
## Alternatively, this file may be used under the terms of the GNU
## General Public License version 2.0 or (at your option) the GNU General
## Public license version 3 or any later version approved by the KDE Free
## Qt Foundation. The licenses are as published by the Free Software
## Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
## included in the packaging of this file. Please review the following
## information to ensure the GNU General Public License requirements will
## be met: https://www.gnu.org/licenses/gpl-2.0.html and
## https://www.gnu.org/licenses/gpl-3.0.html.
##
## $QT_END_LICENSE$
##
#############################################################################
"""AST visitor printing out C++"""
import ast
import sys
import tokenize
import warnings
from .formatter import (CppFormatter, format_for_loop, format_literal,
format_reference, format_start_function_call,
write_import, write_import_from)
from .nodedump import debug_format_node
class ConvertVisitor(ast.NodeVisitor, CppFormatter):
"""AST visitor printing out C++
Note on implementation:
- Any visit_XXX() overridden function should call self.generic_visit(node)
to continue visiting
- When controlling the visiting manually (cf visit_Call()),
self.visit(child) needs to be called since that dispatches to
visit_XXX(). This is usually done to prevent undesired output
for example from references of calls, etc.
"""
debug = False
def __init__(self, file_name, output_file):
ast.NodeVisitor.__init__(self)
CppFormatter.__init__(self, output_file)
self._file_name = file_name
self._class_scope = [] # List of class names
self._stack = [] # nodes
self._debug_indent = 0
@staticmethod
def create_ast(filename):
"""Create an Abstract Syntax Tree on which a visitor can be run"""
node = None
with tokenize.open(filename) as file:
node = ast.parse(file.read(), mode="exec")
return node
def generic_visit(self, node):
parent = self._stack[-1] if self._stack else None
if self.debug:
self._debug_enter(node, parent)
self._stack.append(node)
try:
super().generic_visit(node)
except Exception as e:
line_no = node.lineno if hasattr(node, 'lineno') else -1
error_message = str(e)
message = f'{self._file_name}:{line_no}: Error "{error_message}"'
warnings.warn(message)
self._output_file.write(f'\n// {error_message}\n')
del self._stack[-1]
if self.debug:
self._debug_leave(node)
def visit_Add(self, node):
self.generic_visit(node)
self._output_file.write(' + ')
def visit_Assign(self, node):
self._output_file.write('\n')
self.INDENT()
line_no = node.lineno if hasattr(node, 'lineno') else -1
for target in node.targets:
if isinstance(target, ast.Tuple):
w = f"{self._file_name}:{line_no}: List assignment not handled."
warnings.warn(w)
elif isinstance(target, ast.Subscript):
w = f"{self._file_name}:{line_no}: Subscript assignment not handled."
warnings.warn(w)
else:
self._output_file.write(format_reference(target))
self._output_file.write(' = ')
self.visit(node.value)
self._output_file.write(';\n')
def visit_Attribute(self, node):
"""Format a variable reference (cf visit_Name)"""
self._output_file.write(format_reference(node))
def visit_BinOp(self, node):
# Parentheses are not exposed, so, every binary operation needs to
# be enclosed by ().
self._output_file.write('(')
self.generic_visit(node)
self._output_file.write(')')
def visit_BitAnd(self, node):
self.generic_visit(node)
self._output_file.write(" & ")
def visit_BitOr(self, node):
self.generic_visit(node)
self._output_file.write(" | ")
def visit_Call(self, node):
self._output_file.write(format_start_function_call(node))
# Manually do visit(), skip the children of func
for i, arg in enumerate(node.args):
if i > 0:
self._output_file.write(', ')
self.visit(arg)
self._output_file.write(')')
def visit_ClassDef(self, node):
# Manually do visit() to skip over base classes
# and annotations
self._class_scope.append(node.name)
self.write_class_def(node)
self.indent()
for b in node.body:
self.visit(b)
self.dedent()
self.indent_line('};')
del self._class_scope[-1]
def visit_Eq(self, node):
self.generic_visit(node)
self._output_file.write(" == ")
def visit_Expr(self, node):
self._output_file.write('\n')
self.INDENT()
self.generic_visit(node)
self._output_file.write(';\n')
def visit_Gt(self, node):
self.generic_visit(node)
self._output_file.write(" > ")
def visit_GtE(self, node):
self.generic_visit(node)
self._output_file.write(" >= ")
def visit_For(self, node):
# Manually do visit() to get the indentation right.
# TODO: what about orelse?
self.indent_line(format_for_loop(node))
self.indent()
for b in node.body:
self.visit(b)
self.dedent()
self.indent_line('}')
def visit_FunctionDef(self, node):
class_context = self._class_scope[-1] if self._class_scope else None
self.write_function_def(node, class_context)
self.indent()
self.generic_visit(node)
self.dedent()
self.indent_line('}')
def visit_If(self, node):
# Manually do visit() to get the indentation right. Note:
# elsif() is modelled as nested if.
self.indent_string('if (')
self.visit(node.test)
self._output_file.write(') {\n')
self.indent()
for b in node.body:
self.visit(b)
self.dedent()
self.indent_string('}')
if node.orelse:
self._output_file.write(' else {\n')
self.indent()
for b in node.orelse:
self.visit(b)
self.dedent()
self.indent_string('}')
self._output_file.write('\n')
def visit_Import(self, node):
write_import(self._output_file, node)
def visit_ImportFrom(self, node):
write_import_from(self._output_file, node)
def visit_List(self, node):
# Manually do visit() to get separators right
self._output_file.write('{')
for i, el in enumerate(node.elts):
if i > 0:
self._output_file.write(', ')
self.visit(el)
self._output_file.write('}')
def visit_LShift(self, node):
self.generic_visit(node)
self._output_file.write(" << ")
def visit_Lt(self, node):
self.generic_visit(node)
self._output_file.write(" < ")
def visit_LtE(self, node):
self.generic_visit(node)
self._output_file.write(" <= ")
def visit_Mult(self, node):
self.generic_visit(node)
self._output_file.write(' * ')
def visit_Name(self, node):
"""Format a variable reference (cf visit_Attribute)"""
self._output_file.write(format_reference(node))
def visit_NameConstant(self, node):
self.generic_visit(node)
if node.value is None:
self._output_file.write('nullptr')
elif not node.value:
self._output_file.write('false')
else:
self._output_file.write('true')
def visit_Not(self, node):
self.generic_visit(node)
self._output_file.write("!")
def visit_NotEq(self, node):
self.generic_visit(node)
self._output_file.write(" != ")
def visit_Num(self, node):
self.generic_visit(node)
self._output_file.write(format_literal(node))
def visit_RShift(self, node):
self.generic_visit(node)
self._output_file.write(" >> ")
def visit_Str(self, node):
self.generic_visit(node)
self._output_file.write(format_literal(node))
def visit_UnOp(self, node):
self.generic_visit(node)
def _debug_enter(self, node, parent=None):
message = '{}>generic_visit({})'.format(' ' * self ._debug_indent,
debug_format_node(node))
if parent:
message += ', parent={}'.format(debug_format_node(parent))
message += '\n'
sys.stderr.write(message)
self._debug_indent += 1
def _debug_leave(self, node):
self._debug_indent -= 1
message = '{}<generic_visit({})\n'.format(' ' * self ._debug_indent,
type(node).__name__)
sys.stderr.write(message)
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