# -*- coding: utf-8 -*-
"""Back-port compiler for Python 3.8 assignment expressions."""
import argparse
import os
import pathlib
import re
import sys
import traceback
from typing import Dict, Generator, List, Optional, Union
import f2format
import parso.python.tree
import parso.tree
import tbtrim
from bpc_utils import (BaseContext, BPCSyntaxError, Config, TaskLock, archive_files,
detect_encoding, detect_files, detect_indentation, detect_linesep,
first_non_none, get_parso_grammar_versions, map_tasks, parse_boolean_state,
parse_indentation, parse_linesep, parse_positive_integer, parso_parse,
recover_files)
from bpc_utils import Linesep
from typing_extensions import Literal, TypedDict, final
__all__ = ['main', 'walrus', 'convert']
# version string
__version__ = '0.1.5'
###############################################################################
# Types for annotation
ScopeKeyword = Literal['global', 'nonlocal']
class WalrusConfig(Config):
indentation = '' # type: str
linesep = '\n' # type: Literal[Linesep]
pep8 = True # type: bool
filename = None # Optional[str]
source_version = None # Optional[str]
FunctionEntry = TypedDict('FunctionEntry', {
'name': str,
'uuid': str,
'scope_keyword': ScopeKeyword,
})
LambdaEntry = TypedDict('LambdaEntry', {
'param': str,
'suite': str,
'uuid': str,
})
###############################################################################
# Auxiliaries
#: Get supported source versions.
#:
#: .. seealso:: :func:`bpc_utils.get_parso_grammar_versions`
WALRUS_SOURCE_VERSIONS = get_parso_grammar_versions(minimum='3.8')
# option default values
#: Default value for the ``quiet`` option.
_default_quiet = False
#: Default value for the ``concurrency`` option.
_default_concurrency = None # auto detect
#: Default value for the ``do_archive`` option.
_default_do_archive = True
#: Default value for the ``archive_path`` option.
_default_archive_path = 'archive'
#: Default value for the ``source_version`` option.
_default_source_version = WALRUS_SOURCE_VERSIONS[-1]
#: Default value for the ``linesep`` option.
_default_linesep = None # auto detect
#: Default value for the ``indentation`` option.
_default_indentation = None # auto detect
#: Default value for the ``pep8`` option.
_default_pep8 = True
# option getter utility functions
# option value precedence is: explicit value (CLI/API arguments) > environment variable > default value
[docs]def _get_quiet_option(explicit: Optional[bool] = None) -> Optional[bool]:
"""Get the value for the ``quiet`` option.
Args:
explicit (Optional[bool]): the value explicitly specified by user,
:data:`None` if not specified
Returns:
bool: the value for the ``quiet`` option
:Environment Variables:
:envvar:`WALRUS_QUIET` -- the value in environment variable
See Also:
:data:`_default_quiet`
"""
# We need short circuit evaluation, so first_non_none(a, b, c) does not work here
# with PEP 505 we can simply write a ?? b ?? c
def _option_layers() -> Generator[Optional[bool], None, None]:
yield explicit
yield parse_boolean_state(os.getenv('WALRUS_QUIET'))
yield _default_quiet
return first_non_none(_option_layers())
[docs]def _get_concurrency_option(explicit: Optional[int] = None) -> Optional[int]:
"""Get the value for the ``concurrency`` option.
Args:
explicit (Optional[int]): the value explicitly specified by user,
:data:`None` if not specified
Returns:
Optional[int]: the value for the ``concurrency`` option;
:data:`None` means *auto detection* at runtime
:Environment Variables:
:envvar:`WALRUS_CONCURRENCY` -- the value in environment variable
See Also:
:data:`_default_concurrency`
"""
return parse_positive_integer(explicit or os.getenv('WALRUS_CONCURRENCY') or _default_concurrency)
[docs]def _get_do_archive_option(explicit: Optional[bool] = None) -> Optional[bool]:
"""Get the value for the ``do_archive`` option.
Args:
explicit (Optional[bool]): the value explicitly specified by user,
:data:`None` if not specified
Returns:
bool: the value for the ``do_archive`` option
:Environment Variables:
:envvar:`WALRUS_DO_ARCHIVE` -- the value in environment variable
See Also:
:data:`_default_do_archive`
"""
def _option_layers() -> Generator[Optional[bool], None, None]:
yield explicit
yield parse_boolean_state(os.getenv('WALRUS_DO_ARCHIVE'))
yield _default_do_archive
return first_non_none(_option_layers())
[docs]def _get_archive_path_option(explicit: Optional[str] = None) -> str:
"""Get the value for the ``archive_path`` option.
Args:
explicit (Optional[str]): the value explicitly specified by user,
:data:`None` if not specified
Returns:
str: the value for the ``archive_path`` option
:Environment Variables:
:envvar:`WALRUS_ARCHIVE_PATH` -- the value in environment variable
See Also:
:data:`_default_archive_path`
"""
return explicit or os.getenv('WALRUS_ARCHIVE_PATH') or _default_archive_path
[docs]def _get_source_version_option(explicit: Optional[str] = None) -> Optional[str]:
"""Get the value for the ``source_version`` option.
Args:
explicit (Optional[str]): the value explicitly specified by user,
:data:`None` if not specified
Returns:
str: the value for the ``source_version`` option
:Environment Variables:
:envvar:`WALRUS_SOURCE_VERSION` -- the value in environment variable
See Also:
:data:`_default_source_version`
"""
return explicit or os.getenv('WALRUS_SOURCE_VERSION') or _default_source_version
[docs]def _get_linesep_option(explicit: Optional[str] = None) -> Optional[Linesep]:
r"""Get the value for the ``linesep`` option.
Args:
explicit (Optional[str]): the value explicitly specified by user,
:data:`None` if not specified
Returns:
Optional[Literal['\\n', '\\r\\n', '\\r']]: the value for the ``linesep`` option;
:data:`None` means *auto detection* at runtime
:Environment Variables:
:envvar:`WALRUS_LINESEP` -- the value in environment variable
See Also:
:data:`_default_linesep`
"""
return parse_linesep(explicit or os.getenv('WALRUS_LINESEP') or _default_linesep)
[docs]def _get_indentation_option(explicit: Optional[Union[str, int]] = None) -> Optional[str]:
"""Get the value for the ``indentation`` option.
Args:
explicit (Optional[Union[str, int]]): the value explicitly specified by user,
:data:`None` if not specified
Returns:
Optional[str]: the value for the ``indentation`` option;
:data:`None` means *auto detection* at runtime
:Environment Variables:
:envvar:`WALRUS_INDENTATION` -- the value in environment variable
See Also:
:data:`_default_indentation`
"""
return parse_indentation(explicit or os.getenv('WALRUS_INDENTATION') or _default_indentation)
[docs]def _get_pep8_option(explicit: Optional[bool] = None) -> Optional[bool]:
"""Get the value for the ``pep8`` option.
Args:
explicit (Optional[bool]): the value explicitly specified by user,
:data:`None` if not specified
Returns:
bool: the value for the ``pep8`` option
:Environment Variables:
:envvar:`WALRUS_PEP8` -- the value in environment variable
See Also:
:data:`_default_pep8`
"""
def _option_layers() -> Generator[Optional[bool], None, None]:
yield explicit
yield parse_boolean_state(os.getenv('WALRUS_PEP8'))
yield _default_pep8
return first_non_none(_option_layers())
###############################################################################
# Traceback Trimming (tbtrim)
# root path
ROOT = pathlib.Path(__file__).resolve().parent
def predicate(filename: str) -> bool:
return pathlib.Path(filename).parent == ROOT
tbtrim.set_trim_rule(predicate, strict=True, target=BPCSyntaxError)
###############################################################################
# Main Conversion Implementation
# walrus wrapper template
NAME_TEMPLATE = '''\
if False:
%(indentation)s%(name_list)s = NotImplemented
'''.splitlines() # `str.splitlines` will remove trailing newline
CALL_TEMPLATE = '_walrus_wrapper_%(name)s_%(uuid)s(%(expr)s)'
FUNC_TEMPLATE = '''\
def _walrus_wrapper_%(name)s_%(uuid)s(expr):
%(indentation)s"""Wrapper function for assignment expression."""
%(indentation)s%(scope_keyword)s %(name)s
%(indentation)s%(name)s = expr
%(indentation)sreturn %(name)s
'''.splitlines() # `str.splitlines` will remove trailing newline
# special template for lambda
LAMBDA_CALL_TEMPLATE = '_walrus_wrapper_lambda_%(uuid)s'
LAMBDA_FUNC_TEMPLATE = '''\
def _walrus_wrapper_lambda_%(uuid)s(%(param)s):
%(indentation)s"""Wrapper function for lambda definitions."""
%(indentation)s%(suite)s
'''.splitlines() # `str.splitlines` will remove trailing newline
# special templates for ClassVar
CLS_TEMPLATE = "(__import__('builtins').locals().__setitem__(%(name)r, %(expr)s), %(name)s)[1]"
[docs]class Context(BaseContext):
"""General conversion context.
Args:
node (parso.tree.NodeOrLeaf): parso AST
config (Config): conversion configurations
Keyword Args:
indent_level (int): current indentation level
scope_keyword (Optional[Literal['global', 'nonlocal']]): scope keyword for wrapper function
context (Optional[List[str]]): global context (:term:`namespace`)
raw (bool): raw processing flag
Important:
``raw`` should be :data:`True` only if the ``node`` is in the clause of another *context*,
where the converted wrapper functions should be inserted.
Typically, only if ``node`` is an assignment expression (:token:`namedexpr_test`) node,
``raw`` will be set as :data:`True`, in consideration of nesting assignment expressions.
For the :class:`Context` class of :mod:`walrus` module,
it will process nodes with following methods:
* :token:`suite`
- :meth:`Context._process_suite_node`
- :meth:`ClassContext._process_suite_node`
* :token:`namedexpr_test`
- :meth:`Context._process_namedexpr_test`
- :meth:`ClassContext._process_namedexpr_test`
* :token:`global_stmt`
- :meth:`Context._process_global_stmt`
- :meth:`ClassContext._process_global_stmt`
* :token:`classdef`
- :meth:`Context._process_classdef`
* :token:`funcdef`
- :meth:`Context._process_funcdef`
* :token:`lambdef`
- :meth:`Context._process_lambdef`
* :token:`if_stmt`
- :meth:`Context._process_if_stmt`
* :token:`while_stmt`
- :meth:`Context._process_while_stmt`
* :token:`for_stmt`
- :meth:`Context._process_for_stmt`
* :token:`with_stmt`
- :meth:`Context._process_with_stmt`
* :token:`try_stmt`
- :meth:`Context._process_try_stmt`
* :token:`argument`
- :meth:`Context._process_argument`
* :token:`name`
- :meth:`ClassContext._process_defined_name`
* :token:`nonlocal_stmt`
- :meth:`ClassContext._process_nonlocal_stmt`
* :token:`stringliteral`
* :meth:`Context._process_strings`
* :meth:`Context._process_string_context`
* :meth:`ClassContext._process_strings`
* :meth:`ClassContext._process_string_context`
* :token:`f_string`
* :meth:`Context._process_fstring`
* :meth:`ClassContext._process_fstring`
"""
@final
@property
def lambdef(self) -> List[LambdaEntry]:
"""Lambda definitions (:attr:`self._lamb <walrus.Context._lamb>`).
:rtype: List[LambdaEntry]
"""
return self._lamb
@final
@property
def variables(self) -> List[str]:
"""Assignment expression variable records (:attr:`self._vars <walrus.Context._vars>`).
The variables are the *left-hand-side* variable name of the assignment expressions.
:rtype: List[str]
"""
return self._vars
@final
@property
def functions(self) -> List[FunctionEntry]:
"""Assignment expression wrapper function records (:attr:`self._func <walrus.ontext._func>`).
:rtype: List[FunctionEntry]
"""
return self._func
@final
@property
def global_stmt(self) -> List[str]:
"""List of variables declared in the :token:`global <global_stmt>` statements.
If current root node (:attr:`self._root <walrus.Context._root>`) is a function definition
(:class:`parso.python.tree.Function`), then returns an empty list; else returns
:attr:`self._context <walrus.Context._context>`.
:rtype: List[str]
"""
if self._root.type == 'funcdef':
return []
return self._context
def __init__(self, node: parso.tree.NodeOrLeaf, config: WalrusConfig, *,
indent_level: int = 0, scope_keyword: Optional[ScopeKeyword] = None,
context: Optional[List[str]] = None, raw: bool = False):
if scope_keyword is None:
scope_keyword = self.determine_scope_keyword(node)
if context is None:
context = []
#: Literal['global', 'nonlocal']:
#: The :token:`global <global_stmt>` / :token:`nonlocal <nonlocal_stmt>` keyword.
self._scope_keyword = scope_keyword # type: ScopeKeyword
#: List[str]: Variable names in :token:`global <global_stmt>` statements.
self._context = list(context) # type: List[str]
#: List[str]: Original *left-hand-side* variable names in assignment expressions.
self._vars = [] # type: List[str]
#: List[LambdaEntry]: Converted *lambda* expressions described as :class:`LambdaEntry`.
self._lamb = [] # type: List[LambdaEntry]
#: List[FunctionEntry]: Converted wrapper functions described as :class:`FunctionEntry`.
self._func = [] # type: List[FunctionEntry]
# call super init
super().__init__(node, config, indent_level=indent_level, raw=raw)
[docs] def _process_suite_node(self, node: parso.tree.NodeOrLeaf, func: bool = False,
raw: bool = False, cls_ctx: Optional[str] = None) -> None:
"""Process indented suite (:token:`suite` or others).
Args:
node (parso.tree.NodeOrLeaf): suite node
func (bool): if ``node`` is suite from function definition
raw (bool): raw processing flag
cls_ctx (Optional[str]): class name if ``node`` is in class context
This method first checks if ``node`` contains assignment expression.
If not, it will not perform any processing, rather just append the
original source code to context buffer.
If ``node`` contains assignment expression, then it will initialise another
:class:`Context` instance to perform the conversion process on such
``node``; whilst if ``cls_ctx`` is provided, then it will initialise a
:class:`ClassContext` instance instead.
Note:
If ``func`` is True, when initiating the :class:`Context` instance,
``scope_keyword`` will be set as ``'nonlocal'``, as in the wrapper function
it will refer the original *left-hand-side* variable from the outer
function scope rather than global namespace.
The method will keep *global* statements (:meth:`Context.global_stmt`)
from the temporary :class:`Context` (or :class:`ClassContext`) instance in the
current instance.
And if ``raw`` is set as :data:`True`, the method will keep records of converted wrapper
functions (:meth:`Context.functions`), converted *lambda* expressions (:meth:`Context.lambdef`)
and *left-hand-side* variable names (:meth:`Context.variables`) into current instance as well.
Important:
``raw`` should be :data:`True` only if the ``node`` is in the clause of another *context*,
where the converted wrapper functions should be inserted.
"""
if not self.has_expr(node):
self += node.get_code()
return
indent = self._indent_level + 1
self += self._linesep + self._indentation * indent
if func:
scope_keyword = 'nonlocal' # type: ScopeKeyword
else:
scope_keyword = self._scope_keyword
# process suite
if cls_ctx is None:
ctx = Context(node=node, config=self.config, # type: ignore[arg-type]
context=self._context, indent_level=indent,
scope_keyword=scope_keyword, raw=raw)
else:
ctx = ClassContext(cls_ctx=cls_ctx,
node=node, config=self.config, # type: ignore[arg-type]
context=self._context, indent_level=indent,
scope_keyword=scope_keyword, raw=raw)
self += ctx.string.lstrip()
# keep records
if raw:
self._lamb.extend(ctx.lambdef)
self._vars.extend(ctx.variables)
self._func.extend(ctx.functions)
self._context.extend(ctx.global_stmt)
[docs] def _process_string_context(self, node: parso.python.tree.PythonNode) -> None:
"""Process string contexts (:token:`stringliteral`).
Args:
node (parso.python.tree.PythonNode): string literals node
This method first checks if ``node`` contains assignment expression.
If not, it will not perform any processing, rather just append the
original source code to context buffer. Later it will check if
``node`` contains *debug f-string*. If not, it will process the
*regular* processing on each child of such ``node``.
See Also:
The method calls :meth:`f2format.Context.has_debug_fstring`
to detect *debug f-strings*.
Otherwise, it will initialise a new :class:`StringContext` instance
to perform the conversion process on such ``node``, which will first
use :mod:`f2format` to convert those formatted string literals.
Important:
When initialisation, ``raw`` parameter **must** be set to :data:`True`;
as the converted wrapper functions should be inserted in the *outer*
context, rather than the new :class:`StringContext` instance.
After conversion, the method will keep records of converted wrapper
functions (:meth:`Context.functions`), converted *lambda* expressions (:meth:`Context.lambdef`)
and *left-hand-side* variable names (:meth:`Context.variables`) into current instance as well.
"""
if not self.has_expr(node):
self += node.get_code()
return
if not f2format.Context.has_debug_fstring(node):
for child in node.children:
self._process(child)
return
# initialise new context
ctx = StringContext(node=node, config=self.config, context=self._context, # type: ignore[arg-type]
indent_level=self._indent_level, scope_keyword=self._scope_keyword, raw=True)
self += ctx.string
# keep record
self._lamb.extend(ctx.lambdef)
self._vars.extend(ctx.variables)
self._func.extend(ctx.functions)
self._context.extend(ctx.global_stmt)
[docs] def _process_namedexpr_test(self, node: parso.python.tree.PythonNode) -> None:
"""Process assignment expression (:token:`namedexpr_test`).
Args:
node (parso.python.tree.PythonNode): assignment expression node
This method converts the assignment expression into wrapper function
and extracts related records for inserting converted code.
* The *left-hand-side* variable name will be recorded in
:attr:`self._vars <walrus.Context._vars>`.
* The *right-hand-side* expression will be converted using another
:class:`Context` instance and replaced with a wrapper function call
rendered from :data:`CALL_TEMPLATE`; information described as
:class:`FunctionEntry` will be recorded into :attr:`self._func <walrus.Context._func>`.
"""
# split assignment expression
node_name, _, node_expr = node.children
name = node_name.value
nuid = self._uuid_gen.gen()
# calculate expression string
ctx = Context(node=node_expr, config=self.config, # type: ignore[arg-type]
context=self._context, indent_level=self._indent_level,
scope_keyword=self._scope_keyword, raw=True)
expr = ctx.string.strip()
self._vars.extend(ctx.variables)
self._func.extend(ctx.functions)
# replacing code
code = CALL_TEMPLATE % dict(name=name, uuid=nuid, expr=expr)
prefix, suffix = self.extract_whitespaces(node.get_code())
self += prefix + code + suffix
self._context.extend(ctx.global_stmt)
if name in self._context:
scope_keyword = 'global' # type: ScopeKeyword
else:
scope_keyword = self._scope_keyword
# keep records
self._vars.append(name)
self._func.append(dict(name=name, uuid=nuid, scope_keyword=scope_keyword))
[docs] def _process_global_stmt(self, node: parso.python.tree.GlobalStmt) -> None:
"""Process function definition (:token:`global_stmt`).
Args:
node (parso.python.tree.GlobalStmt): global statement node
This method records all variables declared in a *global* statement
into :attr:`self._context <walrus.Context._context>`.
"""
children = iter(node.children)
# <Keyword: global>
next(children)
# <Name: ...>
name = next(children)
self._context.append(name.value)
while True:
try:
# <Operator: ,>
next(children)
except StopIteration:
break
# <Name: ...>
name = next(children)
self._context.append(name.value)
# process code
self += node.get_code()
[docs] def _process_classdef(self, node: parso.python.tree.Class) -> None:
"""Process class definition (:token:`classdef`).
Args:
node (parso.python.tree.Class): class node
This method converts the whole class suite context with
:meth:`~Context._process_suite_node` through
:class:`ClassContext` respectively.
"""
# <Name: ...>
name = node.name
# <Keyword: class>
# <Name: ...>
# [<Operator: (>, PythonNode(arglist, [...]]), <Operator: )>]
# <Operator: :>
for child in node.children[:-1]:
self._process(child)
# PythonNode(suite, [...]) / PythonNode(simple_stmt, [...])
suite = node.children[-1]
self._process_suite_node(suite, cls_ctx=name.value)
[docs] def _process_funcdef(self, node: parso.python.tree.Function) -> None:
"""Process function definition (:token:`funcdef`).
Args:
node (parso.python.tree.Function): function node
This method converts the function suite with
:meth:`~Context._process_suite_node`.
"""
# 'def' NAME '(' PARAM ')' [ '->' NAME ] ':' SUITE
for child in node.children[:-1]:
self._process(child)
self._process_suite_node(node.children[-1], func=True)
[docs] def _process_lambdef(self, node: parso.python.tree.Lambda) -> None:
"""Process lambda definition (``lambdef``).
Args:
node (parso.python.tree.Lambda): lambda node
This method first checks if ``node`` contains assignment expressions.
If not, it will append the original source code directly to the buffer.
For *lambda* expressions with assignment expressions, this method
will extract the parameter list and initialise a :class:`LambdaContext`
instance to convert the lambda suite. Such information will be recorded
as :class:`LambdaEntry` in :attr:`self._lamb <Context._lamb>`.
.. note:: For :class:`LambdaContext`, ``scope_keyword`` should always be ``'nonlocal'``.
Then it will replace the original lambda expression with a wrapper function
call rendered from :data:`LAMBDA_CALL_TEMPLATE`.
"""
if not self.has_expr(node):
self += node.get_code()
return
children = iter(node.children)
# <Keyword: lambda>
next(children)
# vararglist
para_list = []
for child in children:
if child.type == 'operator' and child.value == ':':
break
para_list.append(child)
param = ''.join(map(lambda n: n.get_code(), para_list))
# test_nocond | test
indent = self._indent_level + 1
ctx = LambdaContext(node=next(children), config=self.config, # type: ignore[arg-type]
context=self._context, indent_level=indent,
scope_keyword='nonlocal')
suite = ctx.string.strip()
# keep record
nuid = self._uuid_gen.gen()
self._lamb.append(dict(param=param, suite=suite, uuid=nuid))
# replacing lambda
self += LAMBDA_CALL_TEMPLATE % dict(uuid=nuid)
[docs] def _process_if_stmt(self, node: parso.python.tree.IfStmt) -> None:
"""Process if statement (:token:`if_stmt`).
Args:
node (parso.python.tree.IfStmt): if node
This method processes each indented suite under the *if*, *elif*,
and *else* statements.
"""
children = iter(node.children)
# <Keyword: if>
self._process(next(children))
# namedexpr_test
self._process(next(children))
# <Operator: :>
self._process(next(children))
# suite
self._process_suite_node(next(children))
while True:
try:
# <Keyword: elif | else>
key = next(children)
except StopIteration:
break
self._process(key)
if key.value == 'elif':
# namedexpr_test
self._process(next(children))
# <Operator: :>
self._process(next(children))
# suite
self._process_suite_node(next(children))
continue
if key.value == 'else':
# <Operator: :>
self._process(next(children))
# suite
self._process_suite_node(next(children))
continue
[docs] def _process_while_stmt(self, node: parso.python.tree.WhileStmt) -> None:
"""Process while statement (:token:`while_stmt`).
Args:
node (parso.python.tree.WhileStmt): while node
This method processes the indented suite under the *while* and optional
*else* statements.
"""
children = iter(node.children)
# <Keyword: while>
self._process(next(children))
# namedexpr_test
self._process(next(children))
# <Operator: :>
self._process(next(children))
# suite
self._process_suite_node(next(children))
try:
key = next(children)
except StopIteration:
return
# <Keyword: else>
self._process(key)
# <Operator: :>
self._process(next(children))
# suite
self._process_suite_node(next(children))
[docs] def _process_for_stmt(self, node: parso.python.tree.ForStmt) -> None:
"""Process for statement (:token:`for_stmt`).
Args:
node (parso.python.tree.ForStmt): for node
This method processes the indented suite under the *for* and optional
*else* statements.
"""
children = iter(node.children)
# <Keyword: for>
self._process(next(children))
# exprlist
self._process(next(children))
# <Keyword: in>
self._process(next(children))
# testlist
self._process(next(children))
# <Operator: :>
self._process(next(children))
# suite
self._process_suite_node(next(children))
try:
key = next(children)
except StopIteration:
return
# <Keyword: else>
self._process(key)
# <Operator: :>
self._process(next(children))
# suite
self._process_suite_node(next(children))
[docs] def _process_with_stmt(self, node: parso.python.tree.WithStmt) -> None:
"""Process with statement (:token:`with_stmt`).
Args:
node (parso.python.tree.WithStmt): with node
This method processes the indented suite under the *with* statement.
"""
children = iter(node.children)
# <Keyword: with>
self._process(next(children))
while True:
# with_item | <Operator: ,>
item = next(children)
self._process(item)
# <Operator: :>
if item.type == 'operator' and item.value == ':':
break
# suite
self._process_suite_node(next(children))
[docs] def _process_try_stmt(self, node: parso.python.tree.TryStmt) -> None:
"""Process try statement (:token:`try_stmt`).
Args:
node (parso.python.tree.TryStmt): try node
This method processes the indented suite under the *try*, *except*,
*else*, and *finally* statements.
"""
children = iter(node.children)
while True:
try:
key = next(children)
except StopIteration:
break
# <Keyword: try | else | finally> | PythonNode(except_clause, [...]
self._process(key)
# <Operator: :>
self._process(next(children))
# suite
self._process_suite_node(next(children))
[docs] def _process_argument(self, node: parso.python.tree.PythonNode) -> None:
"""Process function argument (:token:`argument`).
Args:
node (parso.python.tree.PythonNode): argument node
This method processes arguments from function argument list.
"""
children = iter(node.children)
# test
test = next(children)
try:
# <Operator: :=>
op = next(children)
except StopIteration:
self._process(test)
return
if self.is_walrus(op):
self._process_namedexpr_test(node)
return
# not walrus
self._process(test)
self._process(op)
for child in children:
self._process(child)
[docs] def _process_strings(self, node: parso.python.tree.PythonNode) -> None:
"""Process concatenable strings (:token:`stringliteral`).
Args:
node (parso.python.tree.PythonNode): concatentable strings node
As in Python, adjacent string literals can be concatenated in certain
cases, as described in the `documentation`_. Such concatenable strings
may contain formatted string literals (:term:`f-string`) within its scope.
_documentation: https://docs.python.org/3/reference/lexical_analysis.html#string-literal-concatenation
"""
self._process_string_context(node)
[docs] def _process_fstring(self, node: parso.python.tree.PythonNode) -> None:
"""Process formatted strings (:token:`f_string`).
Args:
node (parso.python.tree.PythonNode): formatted strings node
"""
self._process_string_context(node)
[docs] def _concat(self) -> None:
"""Concatenate final string.
This method tries to inserted the recorded wrapper functions and variables
at the very location where starts to contain assignment expressions, i.e.
between the converted code as :attr:`self._prefix <Context._prefix>` and
:attr:`self._suffix <Context._suffix>`.
The inserted code include variable declaration rendered from
:data:`NAME_TEMPLATE`, wrapper function definitions rendered from
:data:`FUNC_TEMPLATE` and extracted *lambda* expressions rendered from
:data:`LAMBDA_FUNC_TEMPLATE`. If :attr:`self._pep8 <Context._pep8>` is
:data:`True`, it will insert the code in compliance with :pep:`8`.
"""
flag = any((self._vars, self._func, self._lamb)) # if have code to insert
# strip suffix comments
prefix, suffix = self.split_comments(self._suffix, self._linesep)
match = re.match(r'^(?P<linesep>(%s)*)' % self._linesep, suffix, flags=re.ASCII)
suffix_linesep = match.group('linesep') if match is not None else ''
# first, the prefix code
self._buffer += self._prefix + prefix + suffix_linesep
if flag and self._pep8 and self._buffer:
if (self._node_before_expr is not None
and self._node_before_expr.type in ('funcdef', 'classdef')
and self._indent_level == 0):
blank = 2
else:
blank = 1
self._buffer += self._linesep * self.missing_newlines(prefix=self._buffer, suffix='',
expected=blank, linesep=self._linesep)
# then, the variables and functions
indent = self._indentation * self._indent_level
if self._pep8:
linesep = self._linesep * (1 if self._indent_level > 0 else 2)
else:
linesep = ''
if self._vars:
name_list = ' = '.join(sorted(set(self._vars)))
self._buffer += indent + (
'%s%s' % (self._linesep, indent)
).join(NAME_TEMPLATE) % dict(indentation=self._indentation, name_list=name_list) + self._linesep
for func in sorted(self._func, key=lambda func: func['name']):
if self._buffer:
self._buffer += linesep
self._buffer += indent + (
'%s%s' % (self._linesep, indent)
).join(FUNC_TEMPLATE) % dict(indentation=self._indentation, **func) + self._linesep
for lamb in self._lamb:
if self._buffer:
self._buffer += linesep
self._buffer += indent + (
'%s%s' % (self._linesep, indent)
).join(LAMBDA_FUNC_TEMPLATE) % dict(indentation=self._indentation, **lamb) + self._linesep
# finally, the suffix code
if flag and self._pep8:
blank = 2 if self._indent_level == 0 else 1
self._buffer += self._linesep * self.missing_newlines(prefix=self._buffer, suffix=suffix,
expected=blank, linesep=self._linesep)
self._buffer += suffix.lstrip(self._linesep)
[docs] @final
@classmethod
def has_expr(cls, node: parso.tree.NodeOrLeaf) -> bool:
"""Check if node has assignment expression (:token:`namedexpr_test`).
Args:
node (parso.tree.NodeOrLeaf): parso AST
Returns:
bool: if ``node`` has assignment expression
"""
if cls.is_walrus(node):
return True
if hasattr(node, 'children'):
for child in node.children: # type: ignore[attr-defined]
if cls.has_expr(child):
return True
return False
# backward compatibility and auxiliary alias
has_walrus = has_expr
[docs] @final
@classmethod
def determine_scope_keyword(cls, node: parso.tree.NodeOrLeaf) -> ScopeKeyword:
"""Determine scope keyword based on node position.
Args:
node (parso.tree.NodeOrLeaf): parso AST
Returns:
Literal['global', 'nonlocal']: scope keyword
This method recursively perform the following checks on the parents
of ``node``:
* If current ``node`` is a module (:class:`parso.python.tree.Module`),
or a direct child of module then returns ``'global'``.
* If the direct parrent of current ``node`` is a function
(:class:`parso.python.tree.Function`) and/or class
(:class:`parso.python.tree.Class`) definition, then
returns ``'nonlocal'``.
"""
if isinstance(node, parso.python.tree.Module):
return 'global'
parent = node.parent # type: ignore[attr-defined]
if isinstance(parent, parso.python.tree.Module):
return 'global'
if parent.type in ['funcdef', 'classdef']:
return 'nonlocal'
return cls.determine_scope_keyword(parent)
[docs] @final
@staticmethod
def is_walrus(node: parso.tree.NodeOrLeaf) -> bool:
"""Check if ``node`` is assignment expression.
Args:
node (parso.tree.NodeOrLeaf): parso AST
Returns:
bool: if ``node`` is assignment expression
"""
if node.type == 'namedexpr_test':
return True
if node.type == 'operator' and node.value == ':=': # type: ignore[attr-defined]
return True
return False
[docs]class StringContext(Context):
"""String (f-string) conversion context.
This class is mainly used for converting **formatted string literals**.
Args:
node (parso.python.tree.PythonNode): parso AST
config (Config): conversion configurations
Keyword Args:
indent_level (int): current indentation level
scope_keyword (Literal['nonlocal']): scope keyword for wrapper function
context (Optional[List[str]]): global context (:term:`namespace`)
raw (Literal[True]): raw processing flag
Note:
* ``raw`` should always be :data:`True`.
As the conversion in :class:`Context` changes the original expression,
which may change the content of *debug f-string*.
"""
def __init__(self, node: parso.python.tree.PythonNode, config: WalrusConfig, *,
indent_level: int = 0, scope_keyword: Optional[ScopeKeyword] = None,
context: Optional[List[str]] = None, raw: Literal[True] = True):
# convert using f2format first
prefix, suffix = self.extract_whitespaces(node.get_code())
code = f2format.convert(node.get_code().strip())
node = parso_parse(code, filename=config.filename, version=config.source_version) # type: ignore[assignment]
# call super init
super().__init__(node, config, indent_level=indent_level,
scope_keyword=scope_keyword, context=context, raw=raw)
self._buffer = prefix + self._buffer + suffix
[docs]class LambdaContext(Context):
"""Lambda (suite) conversion context.
This class is mainly used for converting **lambda expressions**.
Args:
node (parso.python.tree.Lambda): parso AST
config (Config): conversion configurations
Keyword Args:
indent_level (int): current indentation level
scope_keyword (Literal['nonlocal']): scope keyword for wrapper function
context (Optional[List[str]]): global context (:term:`namespace`)
raw (Literal[False]): raw processing flag
Note:
* ``scope_keyword`` should always be ``'nonlocal'``.
* ``raw`` should always be :data:`False`.
"""
# pylint: disable=useless-super-delegation
def __init__(self, node: parso.tree.NodeOrLeaf, config: WalrusConfig, *,
indent_level: int = 0, scope_keyword: Optional[ScopeKeyword] = None,
context: Optional[List[str]] = None, raw: Literal[False] = False):
super().__init__(node, config, indent_level=indent_level,
scope_keyword=scope_keyword, context=context, raw=raw)
[docs] def _concat(self) -> None:
"""Concatenate final string.
Since conversion of *lambda* expressions doesn't involve inserting
points, this method first simply adds wrapper code to the buffer
(:data:`self._buffer <Context._buffer>`); then it adds a *return*
statement yielding the converted *lambda* suite stored in
:data:`self._prefix <Context._prefix>` and :data:`self._suffix <Context._suffix>`.
The wrapper code include variable declaration rendered from
:data:`NAME_TEMPLATE`, wrapper function definitions rendered from
:data:`FUNC_TEMPLATE` and extracted *lambda* expressions rendered from
:data:`LAMBDA_FUNC_TEMPLATE`. If :attr:`self._pep8 <Context._pep8>` is
:data:`True`, it will insert the code in compliance with :pep:`8`.
"""
flag = self.has_expr(self._root)
# first, the variables and functions
indent = self._indentation * self._indent_level
if self._pep8:
linesep = self._linesep * (1 if self._indent_level > 0 else 2)
else:
linesep = ''
if self._vars:
name_list = ' = '.join(sorted(set(self._vars)))
self._buffer += indent + (
'%s%s' % (self._linesep, indent)
).join(NAME_TEMPLATE) % dict(indentation=self._indentation, name_list=name_list) + self._linesep
for func in sorted(self._func, key=lambda func: func['name']):
if self._buffer:
self._buffer += linesep
self._buffer += indent + (
'%s%s' % (self._linesep, indent)
).join(FUNC_TEMPLATE) % dict(indentation=self._indentation, **func) + self._linesep
for lamb in self._lamb:
if self._buffer:
self._buffer += linesep
self._buffer += indent + (
'%s%s' % (self._linesep, indent)
).join(LAMBDA_FUNC_TEMPLATE) % dict(indentation=self._indentation, **lamb) + self._linesep
if flag and self._pep8:
blank = 2 if self._indent_level == 0 else 1
self._buffer += self._linesep * self.missing_newlines(prefix=self._buffer, suffix=self._prefix,
expected=blank, linesep=self._linesep)
# then, the `return` statement
self._buffer += indent + 'return'
# finally, the source code
self._buffer += self._prefix + self._suffix
[docs]class ClassContext(Context):
"""Class (suite) conversion context.
This class is mainly used for converting *:term:`class variable <class-variable>`*.
Args:
node (parso.python.tree.Class): parso AST
config (Config): conversion configurations
Keyword Args:
cls_ctx (str): class context name
cls_var (Dict[str, str]): mapping for assignment variable and its UUID
indent_level (int): current indentation level
scope_keyword (Optional[Literal['global', 'nonlocal']]): scope keyword for wrapper function
context (Optional[List[str]]): global context (:term:`namespace`)
raw (Literal[False]): raw context processing flag
external (Optional[Dict[str, Literal['global', 'nonlocal']]]):
mapping of :term:`class variable <class-variable>` declared in :token:`global <global_stmt>` and/or
:token:`nonlocal <nonlocal_stmt>` statements
Important:
``raw`` should be :data:`True` only if the ``node`` is in the clause of another *context*,
where the converted wrapper functions should be inserted.
Typically, only if ``node`` is an assignment expression (:token:`namedexpr_test`) node,
``raw`` will be set as :data:`True`, in consideration of nesting assignment expressions.
"""
@final
@property
def cls_var(self) -> Dict[str, str]:
"""Mapping for assignment variable and its UUID (:attr:`self._cls_var <walrus.Context._cls_var>`).
:rtype: Dict[str, str]
"""
return self._cls_var
@final
@property
def external_variables(self) -> Dict[str, ScopeKeyword]:
"""Assignment expression variable records (:attr:`self._ext_vars <walrus.ClassContext._ext_vars>`).
The variables are the *left-hand-side* variable name of the assignment expressions
for :term:`class variable <class-variable>` declared in :token:`global <global_stmt>` and/or
:token:`nonlocal <nonlocal_stmt>` statements.
:rtype: Dict[str, Literal['global', 'nonlocal']]
"""
return self._ext_vars
@final
@property
def external_functions(self) -> List[FunctionEntry]:
"""Assignment expression wrapper function records (:attr:`self._ext_func <walrus.ClassContext._ext_func>`)
for :term:`class variable <class-variable>` declared in :token:`global <global_stmt>` and/or
:token:`nonlocal <nonlocal_stmt>` statements.
:rtype: List[FunctionEntry]
"""
return self._ext_func
def __init__(self, node: parso.python.tree.Class, config: WalrusConfig, *,
cls_ctx: str, cls_var: Optional[Dict[str, str]] = None,
indent_level: int = 0, scope_keyword: Optional[ScopeKeyword] = None,
context: Optional[List[str]] = None, raw: bool = False,
external: Optional[Dict[str, ScopeKeyword]] = None):
if cls_var is None:
cls_var = {}
if external is None:
external = {}
#: bool: Raw context processing flag.
self._cls_raw = raw # type: bool
#: Dict[str, str]: Mapping for assignment variable and its UUID.
self._cls_var = cls_var # type: Dict[str, str]
#: str: Class context name.
self._cls_ctx = cls_ctx # type: str
#: Dict[str, Literal['global', 'nonlocal']]: Original
#: *left-hand-side* variable names in assignment expressions for
#: :term:`class variable <class-variable>` declared in
#: :token:`global <global_stmt>` and/or :token:`nonlocal <nonlocal_stmt>`
#: statements.
self._ext_vars = external # type: Dict[str, ScopeKeyword]
#: List[FunctionEntry]: Converted wrapper functions for :term:`class variable <class-variable>`
#: declared in :token:`global <global_stmt>` and/or :token:`nonlocal <nonlocal_stmt>`
#: statements described as :class:`FunctionEntry`.
self._ext_func = [] # type: List[FunctionEntry]
super().__init__(node=node, config=config, context=context,
indent_level=indent_level, scope_keyword=scope_keyword, raw=raw)
[docs] def _process_suite_node(self, node: parso.tree.NodeOrLeaf, func: bool = False,
raw: bool = False, cls_ctx: Optional[str] = None) -> None:
"""Process indented suite (:token:`suite` or others).
Args:
node (parso.tree.NodeOrLeaf): suite node
func (bool): if ``node`` is suite from function definition
raw (bool): raw processing flag
cls_ctx (Optional[str]): class name if ``node`` is in class context
This method first checks if ``node`` contains assignment expression.
If not, it will not perform any processing, rather just append the
original source code to context buffer.
If ``node`` contains assignment expression, then it will initialise another
:class:`ClassContext` instance to perform the conversion process on such
``node``; whilst if ``func`` is provided, then it will initialise a
:class:`Context` instance instead.
Note:
If ``func`` is True, when initiating the :class:`Context` instance,
``scope_keyword`` will be set as ``'nonlocal'``, as in the wrapper function
it will refer the original *left-hand-side* variable from the outer
function scope rather than global namespace.
The method will keep *global* statements (:meth:`Context.global_stmt`)
from the temporary :class:`Context` (or :class:`ClassContext`) instance in the
current instance.
And if ``raw`` is set as :data:`True`, the method will keep records of converted wrapper
functions (:meth:`Context.functions`), converted *lambda* expressions (:meth:`Context.lambdef`)
and *left-hand-side* variable names (:meth:`Context.variables`), class variable
(:meth:`ClassContext.cls_var`), external variables (:meth:`ClassContext.external_variables`),
wrapper functions for external variables (:meth:`ClassContext.external_functions`) into current
instance as well.
Important:
``raw`` should be :data:`True` only if the ``node`` is in the clause of another *context*,
where the converted wrapper functions should be inserted.
"""
if not self.has_expr(node):
self += node.get_code()
return
indent = self._indent_level + 1
self += self._linesep + self._indentation * indent
if cls_ctx is None:
cls_ctx = self._cls_ctx
cls_var = self._cls_var
if func:
scope_keyword = 'nonlocal' # type: ScopeKeyword
# process suite
ctx = Context(node=node, config=self.config, # type: ignore[arg-type]
context=self._context, indent_level=indent,
scope_keyword=scope_keyword, raw=raw)
else:
scope_keyword = self._scope_keyword
# process suite
ctx = ClassContext(node=node, config=self.config, # type: ignore[arg-type]
cls_ctx=cls_ctx, cls_var=cls_var,
context=self._context, indent_level=indent,
scope_keyword=scope_keyword, raw=raw, external=self._ext_vars)
self += ctx.string.lstrip()
# keep record
if raw:
self._lamb.extend(ctx.lambdef)
self._vars.extend(ctx.variables)
self._func.extend(ctx.functions)
if not func:
self._cls_var.update(ctx.cls_var) # type: ignore[attr-defined]
self._ext_vars.update(ctx.external_variables) # type: ignore[attr-defined]
self._ext_func.extend(ctx.external_functions) # type: ignore[attr-defined]
self._context.extend(ctx.global_stmt)
[docs] def _process_string_context(self, node: parso.python.tree.PythonNode) -> None:
"""Process string contexts (:token:`stringliteral`).
Args:
node (parso.python.tree.PythonNode): string literals node
This method first checks if ``node`` contains assignment expression.
If not, it will not perform any processing, rather just append the
original source code to context buffer.
If ``node`` contains assignment expression, then it will initialise a new
:class:`ClassStringContext` instance to perform the conversion process
on such ``node``, which will first use :mod:`f2format` to convert those
formatted string literals.
Important:
When initialisation, ``raw`` parameter **must** be set to :data:`True`;
as the converted wrapper functions should be inserted in the *outer*
context, rather than the new :class:`ClassStringContext` instance.
After conversion, the method will keep records of converted wrapper
functions (:attr:`Context.functions`), converted *lambda* expressions (:attr:`Context.lambdef`)
and *left-hand-side* variable names (:attr:`Context.variables`), class variable
(:attr:`ClassContext.cls_var`), external variables (:attr:`ClassContext.external_variables`),
wrapper functions for external variables (:attr:`ClassContext.external_functions`) into current
instance as well.
"""
if not self.has_expr(node):
self += node.get_code()
return
# initialise new context
ctx = ClassStringContext(node=node, config=self.config, # type: ignore[arg-type]
cls_ctx=self._cls_ctx, cls_var=self._cls_var,
context=self._context, indent_level=self._indent_level,
scope_keyword=self._scope_keyword, raw=True, external=self._ext_vars)
self += ctx.string
# keep record
self._lamb.extend(ctx.lambdef)
self._vars.extend(ctx.variables)
self._func.extend(ctx.functions)
self._cls_var.update(ctx.cls_var)
self._ext_vars.update(ctx.external_variables)
self._ext_func.extend(ctx.external_functions)
self._context.extend(ctx.global_stmt)
[docs] def _process_namedexpr_test(self, node: parso.python.tree.PythonNode) -> None:
"""Process assignment expression (:token:`namedexpr_test`).
Args:
node (parso.python.tree.PythonNode): assignment expression node
This method converts the assignment expression into wrapper function
and extracts related records for inserting converted code.
* The *left-hand-side* variable name will be recorded in
:attr:`self._vars <walrus.Context._vars>`; and its corresponding UUID will
be recorded in :attr:`self._cls_var <ClassContext._cls_var>`.
* The *right-hand-side* expression will be converted using another
:class:`ClassContext` instance and replaced with a wrapper tuple with
attribute setting from :data:`CLS_TEMPLATE`; information described as
:class:`FunctionEntry` will be recorded into :attr:`self._func <walrus.Context._func>`.
Important:
:class:`~walrus.ClassContext` will `mangle`_ *left-hand-side* variable name
through :meth:`self.mangle <bpc_utils.BaseContext.mangle>` when converting.
.. _mangle: https://docs.python.org/3/reference/expressions.html?highlight=mangling#atom-identifiers
For special :term:`class variable <class-variable>` declared in :token:`global <global_stmt>`
and/or :token:`nonlocal <nonlocal_stmt>` statements:
* The *left-hand-side* variable name will **NOT** be considered as *class variable*,
thus shall **NOT** be recorded.
* The expression will be replaced with a wrapper function call rendered from
:data:`CALL_TEMPLATE`; information described as :class:`FunctionEntry` will be
recorded into :attr:`self._ext_func <walrus.ClassContext._ext_func>` instead.
"""
# split assignment expression
node_name, _, node_expr = node.children
name = node_name.value
nuid = self._uuid_gen.gen()
# calculate expression string
ctx = ClassContext(node=node_expr, config=self.config, # type: ignore[arg-type]
cls_ctx=self._cls_ctx, cls_var=self._cls_var,
context=self._context, indent_level=self._indent_level,
scope_keyword=self._scope_keyword, raw=True,
external=self._ext_vars)
expr = ctx.string.strip()
self._lamb.extend(ctx.lambdef)
self._vars.extend(ctx.variables)
self._func.extend(ctx.functions)
self._context.extend(ctx.global_stmt)
self._cls_var.update(ctx.cls_var)
self._ext_vars.update(ctx.external_variables)
self._ext_func.extend(ctx.external_functions)
# if declared in global/nonlocal statements
external = name in self._ext_vars
# replacing code
if external:
code = CALL_TEMPLATE % dict(name=name, uuid=nuid, expr=expr)
else:
code = CLS_TEMPLATE % dict(name=self.mangle(self._cls_ctx, name), expr=expr)
prefix, suffix = self.extract_whitespaces(node.get_code())
self += prefix + code + suffix
if external:
self._ext_func.append(dict(name=name, uuid=nuid, scope_keyword=self._ext_vars[name]))
return
if name in self._context:
scope_keyword = 'global' # type: ScopeKeyword
else:
scope_keyword = self._scope_keyword
# keep records
self._vars.append(name)
self._func.append(dict(name=name, uuid=nuid, scope_keyword=scope_keyword))
self._cls_var[self.mangle(self._cls_ctx, name)] = nuid
[docs] def _process_defined_name(self, node: parso.python.tree.Name) -> None:
"""Process defined name (:token:`name`).
Args:
node (parso.python.tree.Name): defined name node
This method processes name of defined :term:`class variable <class-variable>`. The original
variable name will be recorded in :attr:`self._vars <walrus.Context._vars>`;
its corresponding UUID will be recorded in :attr:`self._cls_var <ClassContext._cls_var>`;
information described as :class:`FunctionEntry` will be recorded into
:attr:`self._func <walrus.Context._func>`.
Note:
If the *left-hand-side* variable was declared in :token:`global <global_stmt>`
and/or :token:`nonlocal <nonlocal_stmt>`, then it shall **NOT** be
considered as *class variable*.
"""
name = node.value
self += node.get_code()
# if declared in global/nonlocal statements
if name in self._ext_vars:
return
name = self.mangle(self._cls_ctx, name)
nuid = self._uuid_gen.gen()
self._vars.append(name)
self._func.append(dict(name=name, uuid=nuid, scope_keyword=self._scope_keyword))
self._cls_var[self.mangle(self._cls_ctx, name)] = nuid
[docs] def _process_expr_stmt(self, node: parso.python.tree.ExprStmt) -> None:
"""Process variable name (:token:`expr_stmt`).
Args:
node (parso.python.tree.ExprStmt): expression statement
This method processes expression statements in the class context.
It will search for *left-hand-side* variable names of defined
class variables and call :meth:`~ClassContext._process_defined_name`
to process such nodes.
"""
# right hand side expression
rhs = node.get_rhs()
for child in node.children:
if child == rhs:
self._process(child)
continue
if child.type == 'name':
self._process_defined_name(child)
continue
self += child.get_code()
[docs] def _process_global_stmt(self, node: parso.python.tree.GlobalStmt) -> None:
"""Process function definition (:token:`global_stmt`).
Args:
node (parso.python.tree.GlobalStmt): global statement node
This method records all variables declared in a *global* statement
into :attr:`self._context <walrus.Context._context>` and
:attr:`self._ext_vars <walrus.ClassContext._ext_vars>`.
"""
children = iter(node.children)
# <Keyword: global>
next(children)
# <Name: ...>
name = next(children)
self._context.append(name.value)
self._ext_vars[name.value] = 'global'
while True:
try:
# <Operator: ,>
next(children)
except StopIteration:
break
# <Name: ...>
name = next(children)
self._context.append(name.value)
self._ext_vars[name.value] = 'global'
# process code
self += node.get_code()
[docs] def _process_nonlocal_stmt(self, node: parso.python.tree.KeywordStatement) -> None:
"""Process function definition (:token:`nonlocal_stmt`).
Args:
node (parso.python.tree.KeywordStatement): nonlocal statement node
This method records all variables declared in a *nonlocal* statement
into :attr:`self._ext_vars <walrus.ClassContext._ext_vars>`.
"""
children = iter(node.children)
# <Keyword: nonlocal>
next(children)
# <Name: ...>
name = next(children)
self._ext_vars[name.value] = 'nonlocal'
while True:
try:
# <Operator: ,>
next(children)
except StopIteration:
break
# <Name: ...>
name = next(children)
self._ext_vars[name.value] = 'nonlocal'
# process code
self += node.get_code()
[docs] def _concat(self) -> None:
"""Concatenate final string.
This method tries to inserted the recorded wrapper functions and variables
at the very location where starts to contain assignment expressions, i.e.
between the converted code as :attr:`self._prefix <Context._prefix>` and
:attr:`self._suffix <Context._suffix>`.
For special :term:`class variable <class-variable>` declared in :token:`global <global_stmt>`
and/or :token:`nonlocal <nonlocal_stmt>` statements, when assigning to
to such variables, i.e. they are on *left-hand-side* of assignment
expressions, the expressions will be assigned with a wrapper function
rendered from :data:`FUNC_TEMPLATE`.
"""
flag = self.has_expr(self._root)
# strip suffix comments
prefix, suffix = self.split_comments(self._suffix, self._linesep)
match = re.match(r'^(?P<linesep>(%s)*)' % self._linesep, suffix, flags=re.ASCII)
suffix_linesep = match.group('linesep') if match is not None else ''
# first, the prefix code
self._buffer += self._prefix + prefix + suffix_linesep
# then, the class and functions
indent = self._indentation * self._indent_level
linesep = self._linesep
if flag and self._pep8:
if (self._node_before_expr is not None
and self._node_before_expr.type in ('funcdef', 'classdef')
and self._indent_level == 0):
blank = 2
else:
blank = 1
self._buffer += self._linesep * self.missing_newlines(prefix=self._buffer, suffix='',
expected=blank, linesep=self._linesep)
for index, func in enumerate(sorted(self._ext_func, key=lambda func: func['name'])):
if index > 0:
self._buffer += linesep
self._buffer += indent + (
'%s%s' % (self._linesep, indent)
).join(FUNC_TEMPLATE) % dict(indentation=self._indentation, cls=self._cls_ctx, **func) + linesep
for lamb in self._lamb:
if self._buffer:
self._buffer += linesep
self._buffer += indent + (
'%s%s' % (self._linesep, indent)
).join(LAMBDA_FUNC_TEMPLATE) % dict(indentation=self._indentation, **lamb) + linesep
# finally, the suffix code
if flag and self._pep8:
blank = 2 if self._indent_level == 0 else 1
self._buffer += self._linesep * self.missing_newlines(prefix=self._buffer, suffix=suffix,
expected=blank, linesep=self._linesep)
self._buffer += suffix.lstrip(self._linesep)
[docs]class ClassStringContext(ClassContext):
"""String (f-string) conversion context.
This class is mainly used for converting **formatted string literals**
inside a class suite (:term:`ClassVar <class-variable>`).
Args:
node (parso.python.tree.PythonNode): parso AST
config (Config): conversion configurations
Keyword Args:
cls_ctx (str): class context name
cls_var (Dict[str, str]): mapping for assignment variable and its UUID
indent_level (int): current indentation level
scope_keyword (Optional[Literal['global', 'nonlocal']]): scope keyword for wrapper function
context (Optional[List[str]]): global context (:term:`namespace`)
raw (Literal[True]): raw context processing flag
external (Optional[Dict[str, Literal['global', 'nonlocal']]]):
mapping of :term:`class variable <class-variable>` declared in :token:`global <global_stmt>` and/or
:token:`nonlocal <nonlocal_stmt>` statements
Note:
``raw`` should always be :data:`True`.
As the conversion in :class:`ClassContext` introduced quotes (``'``)
into the converted code, it may cause conflicts on the string parsing
if the assignment expression was inside a formatted string literal.
Therefore, we will use :mod:`f2format` ahead to convert such formatted
string literals into normal :func:`str.format` calls then convert any assignment
expressions it may contain.
"""
def __init__(self, node: parso.python.tree.PythonNode, config: WalrusConfig, *,
cls_ctx: str, cls_var: Optional[Dict[str, str]] = None,
indent_level: int = 0, scope_keyword: Optional[ScopeKeyword] = None,
context: Optional[List[str]] = None, raw: Literal[True] = True,
external: Optional[Dict[str, ScopeKeyword]] = None):
# convert using f2format first
prefix, suffix = self.extract_whitespaces(node.get_code())
code = f2format.convert(node.get_code().strip())
node = parso_parse(code, filename=config.filename, version=config.source_version) # type: ignore[assignment]
# call super init
super().__init__(node=node, config=config, cls_ctx=cls_ctx, cls_var=cls_var, # type: ignore[arg-type]
context=context, indent_level=indent_level, scope_keyword=scope_keyword,
raw=raw, external=external)
self._buffer = prefix + self._buffer + suffix
###############################################################################
# Public Interface
[docs]def convert(code: Union[str, bytes], filename: Optional[str] = None, *,
source_version: Optional[str] = None, linesep: Optional[Linesep] = None,
indentation: Optional[Union[int, str]] = None, pep8: Optional[bool] = None) -> str:
"""Convert the given Python source code string.
Args:
code (Union[str, bytes]): the source code to be converted
filename (Optional[str]): an optional source file name to provide a context in case of error
Keyword Args:
source_version (Optional[str]): parse the code as this Python version (uses the latest version by default)
linesep (Optional[:data:`~bpc_utils.Linesep`]): line separator of code (``LF``, ``CRLF``, ``CR``)
(auto detect by default)
indentation (Optional[Union[int, str]]): code indentation style, specify an integer for the number of spaces,
or ``'t'``/``'tab'`` for tabs (auto detect by default)
pep8 (Optional[bool]): whether to make code insertion :pep:`8` compliant
:Environment Variables:
- :envvar:`WALRUS_SOURCE_VERSION` -- same as the ``source_version`` argument and the ``--source-version`` option
in CLI
- :envvar:`WALRUS_LINESEP` -- same as the `linesep` `argument` and the ``--linesep`` option in CLI
- :envvar:`WALRUS_INDENTATION` -- same as the ``indentation`` argument and the ``--indentation`` option in CLI
- :envvar:`WALRUS_PEP8` -- same as the ``pep8`` argument and the ``--no-pep8`` option in CLI (logical negation)
Returns:
str: converted source code
"""
# parse source string
source_version = _get_source_version_option(source_version)
module = parso_parse(code, filename=filename, version=source_version)
# get linesep, indentation and pep8 options
linesep = _get_linesep_option(linesep)
indentation = _get_indentation_option(indentation)
if linesep is None:
linesep = detect_linesep(code)
if indentation is None:
indentation = detect_indentation(code)
pep8 = _get_pep8_option(pep8)
# pack conversion configuration
config = Config(linesep=linesep, indentation=indentation, pep8=pep8,
filename=filename, source_version=source_version)
# convert source string
result = Context(module, config).string # type: ignore[arg-type]
# return conversion result
return result
[docs]def walrus(filename: str, *, source_version: Optional[str] = None, linesep: Optional[Linesep] = None,
indentation: Optional[Union[int, str]] = None, pep8: Optional[bool] = None,
quiet: Optional[bool] = None, dry_run: bool = False) -> None:
"""Convert the given Python source code file. The file will be overwritten.
Args:
filename (str): the file to convert
Keyword Args:
source_version (Optional[str]): parse the code as this Python version (uses the latest version by default)
linesep (Optional[:data:`~bpc_utils.Linesep`]): line separator of code (``LF``, ``CRLF``, ``CR``)
(auto detect by default)
indentation (Optional[Union[int, str]]): code indentation style, specify an integer for the number of spaces,
or ``'t'``/``'tab'`` for tabs (auto detect by default)
pep8 (Optional[bool]): whether to make code insertion :pep:`8` compliant
quiet (Optional[bool]): whether to run in quiet mode
dry_run (bool): if :data:`True`, only print the name of the file to convert but do not perform any conversion
:Environment Variables:
- :envvar:`WALRUS_SOURCE_VERSION` -- same as the ``source-version`` argument and the ``--source-version`` option
in CLI
- :envvar:`WALRUS_LINESEP` -- same as the ``linesep`` argument and the ``--linesep`` option in CLI
- :envvar:`WALRUS_INDENTATION` -- same as the ``indentation`` argument and the ``--indentation`` option in CLI
- :envvar:`WALRUS_PEP8` -- same as the ``pep8`` argument and the ``--no-pep8`` option in CLI (logical negation)
- :envvar:`WALRUS_QUIET` -- same as the ``quiet`` argument and the ``--quiet`` option in CLI
"""
quiet = _get_quiet_option(quiet)
if not quiet:
with TaskLock():
print('Now converting: %r' % filename, file=sys.stderr)
if dry_run:
return
# read file content
with open(filename, 'rb') as file:
content = file.read()
# detect source code encoding
try:
encoding = detect_encoding(content)
except SyntaxError as e:
raise BPCSyntaxError('failed to detect encoding for source file %r: %s' % (filename, e)) from None
# do the dirty things
result = convert(content, filename=filename, source_version=source_version,
linesep=linesep, indentation=indentation, pep8=pep8)
# overwrite the file with conversion result
with open(filename, 'w', encoding=encoding, newline='') as file:
file.write(result)
###############################################################################
# CLI & Entry Point
# option values display
# these values are only intended for argparse help messages
# this shows default values by default, environment variables may override them
__cwd__ = os.getcwd()
__walrus_quiet__ = 'quiet mode' if _get_quiet_option() else 'non-quiet mode'
__walrus_concurrency__ = _get_concurrency_option() or 'auto detect'
__walrus_do_archive__ = 'will do archive' if _get_do_archive_option() else 'will not do archive'
__walrus_archive_path__ = os.path.join(__cwd__, _get_archive_path_option())
__walrus_source_version__ = _get_source_version_option()
__walrus_linesep__ = {
'\n': 'LF',
'\r\n': 'CRLF',
'\r': 'CR',
None: 'auto detect'
}[_get_linesep_option()]
__walrus_indentation__ = _get_indentation_option()
if __walrus_indentation__ is None:
__walrus_indentation__ = 'auto detect'
elif __walrus_indentation__ == '\t':
__walrus_indentation__ = 'tab'
else:
__walrus_indentation__ = '%d spaces' % len(__walrus_indentation__)
__walrus_pep8__ = 'will conform to PEP 8' if _get_pep8_option() else 'will not conform to PEP 8'
[docs]def get_parser() -> argparse.ArgumentParser:
"""Generate CLI parser.
Returns:
argparse.ArgumentParser: CLI parser for walrus
"""
parser = argparse.ArgumentParser(prog='walrus',
usage='walrus [options] <Python source files and directories...>',
description='Back-port compiler for Python 3.8 assignment expressions.')
parser.add_argument('-V', '--version', action='version', version=__version__)
parser.add_argument('-q', '--quiet', action='store_true', default=None,
help='run in quiet mode (current: %s)' % __walrus_quiet__)
parser.add_argument('-C', '--concurrency', action='store', type=int, metavar='N',
help='the number of concurrent processes for conversion (current: %s)' % __walrus_concurrency__)
parser.add_argument('--dry-run', action='store_true',
help='list the files to be converted without actually performing conversion and archiving')
parser.add_argument('-s', '--simple', action='store', nargs='?', dest='simple_args', const='', metavar='FILE',
help='this option tells the program to operate in "simple mode"; '
'if a file name is provided, the program will convert the file but print conversion '
'result to standard output instead of overwriting the file; '
'if no file names are provided, read code for conversion from standard input and print '
'conversion result to standard output; '
'in "simple mode", no file names shall be provided via positional arguments')
archive_group = parser.add_argument_group(title='archive options',
description="backup original files in case there're any issues")
archive_group.add_argument('-na', '--no-archive', action='store_false', dest='do_archive', default=None,
help='do not archive original files (current: %s)' % __walrus_do_archive__)
archive_group.add_argument('-k', '--archive-path', action='store', default=__walrus_archive_path__, metavar='PATH',
help='path to archive original files (current: %(default)s)')
archive_group.add_argument('-r', '--recover', action='store', dest='recover_file', metavar='ARCHIVE_FILE',
help='recover files from a given archive file')
archive_group.add_argument('-r2', action='store_true', help='remove the archive file after recovery')
archive_group.add_argument('-r3', action='store_true', help='remove the archive file after recovery, '
'and remove the archive directory if it becomes empty')
convert_group = parser.add_argument_group(title='convert options', description='conversion configuration')
convert_group.add_argument('-vs', '-vf', '--source-version', '--from-version', action='store', metavar='VERSION',
default=__walrus_source_version__, choices=WALRUS_SOURCE_VERSIONS,
help='parse source code as this Python version (current: %(default)s)')
convert_group.add_argument('-l', '--linesep', action='store',
help='line separator (LF, CRLF, CR) to read '
'source files (current: %s)' % __walrus_linesep__)
convert_group.add_argument('-t', '--indentation', action='store', metavar='INDENT',
help='code indentation style, specify an integer for the number of spaces, '
"or 't'/'tab' for tabs (current: %s)" % __walrus_indentation__)
convert_group.add_argument('-n8', '--no-pep8', action='store_false', dest='pep8', default=None,
help='do not make code insertion PEP 8 compliant (current: %s)' % __walrus_pep8__)
parser.add_argument('files', action='store', nargs='*', metavar='<Python source files and directories...>',
help='Python source files and directories to be converted')
return parser
def do_walrus(filename: str, **kwargs: object) -> None:
"""Wrapper function to catch exceptions."""
try:
walrus(filename, **kwargs) # type: ignore[arg-type]
except Exception: # pylint: disable=broad-except
with TaskLock():
print('Failed to convert file: %r' % filename, file=sys.stderr)
traceback.print_exc()
[docs]def main(argv: Optional[List[str]] = None) -> int:
"""Entry point for walrus.
Args:
argv (Optional[List[str]]): CLI arguments
Returns:
int: program exit code
:Environment Variables:
- :envvar:`WALRUS_QUIET` -- same as the ``--quiet`` option in CLI
- :envvar:`WALRUS_CONCURRENCY` -- same as the ``--concurrency`` option in CLI
- :envvar:`WALRUS_DO_ARCHIVE` -- same as the ``--no-archive`` option in CLI (logical negation)
- :envvar:`WALRUS_ARCHIVE_PATH` -- same as the ``--archive-path`` option in CLI
- :envvar:`WALRUS_SOURCE_VERSION` -- same as the ``--source-version`` option in CLI
- :envvar:`WALRUS_LINESEP` -- same as the ``--linesep`` option in CLI
- :envvar:`WALRUS_INDENTATION` -- same as the ``--indentation`` option in CLI
- :envvar:`WALRUS_PEP8` -- same as the ``--no-pep8`` option in CLI (logical negation)
"""
parser = get_parser()
args = parser.parse_args(argv)
options = {
'source_version': args.source_version,
'linesep': args.linesep,
'indentation': args.indentation,
'pep8': args.pep8,
}
# check if running in simple mode
if args.simple_args is not None:
if args.files:
parser.error('no Python source files or directories shall be given as positional arguments in simple mode')
if not args.simple_args: # read from stdin
code = sys.stdin.read()
else: # read from file
filename = args.simple_args
options['filename'] = filename
with open(filename, 'rb') as file:
code = file.read()
sys.stdout.write(convert(code, **options)) # print conversion result to stdout
return 0
# get options
quiet = _get_quiet_option(args.quiet)
processes = _get_concurrency_option(args.concurrency)
do_archive = _get_do_archive_option(args.do_archive)
archive_path = _get_archive_path_option(args.archive_path)
# check if doing recovery
if args.recover_file:
recover_files(args.recover_file)
if not args.quiet:
print('Recovered files from archive: %r' % args.recover_file, file=sys.stderr)
# TODO: maybe implement deletion in bpc-utils?
if args.r2 or args.r3:
os.remove(args.recover_file)
if args.r3:
archive_dir = os.path.dirname(os.path.realpath(args.recover_file))
if not os.listdir(archive_dir):
os.rmdir(archive_dir)
return 0
# fetch file list
if not args.files:
parser.error('no Python source files or directories are given')
filelist = sorted(detect_files(args.files))
# terminate if no valid Python source files detected
if not filelist:
if not args.quiet:
# TODO: maybe use parser.error?
print('Warning: no valid Python source files found in %r' % args.files, file=sys.stderr)
return 1
# make archive
if do_archive and not args.dry_run:
archive_files(filelist, archive_path)
# process files
options.update({
'quiet': quiet,
'dry_run': args.dry_run,
})
map_tasks(do_walrus, filelist, kwargs=options, processes=processes)
return 0
if __name__ == '__main__':
sys.exit(main())
