Backport PR #14601: Deprecate inputtransformer since 7.0

IPython/core/inputtransformer.py

@@ -1,544 +1,577
 """DEPRECATED: Input transformer classes to support IPython special syntax.
 
 This module was deprecated in IPython 7.0, in favour of inputtransformer2.
 
 This includes the machinery to recognise and transform ``%magic`` commands,
 ``!system`` commands, ``help?`` querying, prompt stripping, and so forth.
 """
 import abc
 import functools
 import re
 import tokenize
+import warnings
 from tokenize import untokenize, TokenError
 from io import StringIO
 
 from IPython.core.splitinput import LineInfo
 from IPython.utils import tokenutil
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 # The escape sequences that define the syntax transformations IPython will
 # apply to user input.  These can NOT be just changed here: many regular
 # expressions and other parts of the code may use their hardcoded values, and
 # for all intents and purposes they constitute the 'IPython syntax', so they
 # should be considered fixed.
 
 ESC_SHELL  = '!'     # Send line to underlying system shell
 ESC_SH_CAP = '!!'    # Send line to system shell and capture output
 ESC_HELP   = '?'     # Find information about object
 ESC_HELP2  = '??'    # Find extra-detailed information about object
 ESC_MAGIC  = '%'     # Call magic function
 ESC_MAGIC2 = '%%'    # Call cell-magic function
 ESC_QUOTE  = ','     # Split args on whitespace, quote each as string and call
 ESC_QUOTE2 = ';'     # Quote all args as a single string, call
 ESC_PAREN  = '/'     # Call first argument with rest of line as arguments
 
 ESC_SEQUENCES = [ESC_SHELL, ESC_SH_CAP, ESC_HELP ,\
                  ESC_HELP2, ESC_MAGIC, ESC_MAGIC2,\
                  ESC_QUOTE, ESC_QUOTE2, ESC_PAREN ]
 
 
 class InputTransformer(metaclass=abc.ABCMeta):
     """Abstract base class for line-based input transformers."""
     
+    def __init__(self):
+        warnings.warn(
+            "`InputTransformer` has been deprecated since IPython 7.0"
+            " and emit a warnig since IPython 8.31, it"
+            " will be removed in the future",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+
     @abc.abstractmethod
     def push(self, line):
         """Send a line of input to the transformer, returning the transformed
         input or None if the transformer is waiting for more input.
 
         Must be overridden by subclasses.
 
         Implementations may raise ``SyntaxError`` if the input is invalid. No
         other exceptions may be raised.
         """
         pass
     
     @abc.abstractmethod
     def reset(self):
         """Return, transformed any lines that the transformer has accumulated,
         and reset its internal state.
 
         Must be overridden by subclasses.
         """
         pass
     
     @classmethod
     def wrap(cls, func):
         """Can be used by subclasses as a decorator, to return a factory that
         will allow instantiation with the decorated object.
         """
         @functools.wraps(func)
         def transformer_factory(**kwargs):
             return cls(func, **kwargs)  # type: ignore [call-arg]
 
         return transformer_factory
 
 class StatelessInputTransformer(InputTransformer):
     """Wrapper for a stateless input transformer implemented as a function."""
     def __init__(self, func):
+        super().__init__()
+        warnings.warn(
+            "`StatelessInputTransformer` has been deprecated since IPython 7.0"
+            " and emit a warnig since IPython 8.31, it"
+            " will be removed in the future",
+            DeprecationWarning,
+            stacklevel=2,
+        )
         self.func = func
     
     def __repr__(self):
         return "StatelessInputTransformer(func={0!r})".format(self.func)
     
     def push(self, line):
         """Send a line of input to the transformer, returning the
         transformed input."""
         return self.func(line)
     
     def reset(self):
         """No-op - exists for compatibility."""
         pass
 
 class CoroutineInputTransformer(InputTransformer):
     """Wrapper for an input transformer implemented as a coroutine."""
     def __init__(self, coro, **kwargs):
         # Prime it
+        super().__init__()
+        warnings.warn(
+            "`CoroutineInputTransformer` has been deprecated since IPython 7.0"
+            " and emit a warnig since IPython 8.31, it"
+            " will be removed in the future",
+            DeprecationWarning,
+            stacklevel=2,
+        )
         self.coro = coro(**kwargs)
         next(self.coro)
     
     def __repr__(self):
         return "CoroutineInputTransformer(coro={0!r})".format(self.coro)
     
     def push(self, line):
         """Send a line of input to the transformer, returning the
         transformed input or None if the transformer is waiting for more
         input.
         """
         return self.coro.send(line)
     
     def reset(self):
         """Return, transformed any lines that the transformer has
         accumulated, and reset its internal state.
         """
         return self.coro.send(None)
 
 class TokenInputTransformer(InputTransformer):
     """Wrapper for a token-based input transformer.
     
     func should accept a list of tokens (5-tuples, see tokenize docs), and
     return an iterable which can be passed to tokenize.untokenize().
     """
     def __init__(self, func):
+        warnings.warn(
+            "`CoroutineInputTransformer` has been deprecated since IPython 7.0"
+            " and emit a warnig since IPython 8.31, it"
+            " will be removed in the future",
+            DeprecationWarning,
+            stacklevel=2,
+        )
         self.func = func
         self.buf = []
         self.reset_tokenizer()
 
     def reset_tokenizer(self):
         it = iter(self.buf)
         self.tokenizer = tokenutil.generate_tokens_catch_errors(it.__next__)
 
     def push(self, line):
         self.buf.append(line + '\n')
         if all(l.isspace() for l in self.buf):
             return self.reset()
 
         tokens = []
         stop_at_NL = False
         try:
             for intok in self.tokenizer:
                 tokens.append(intok)
                 t = intok[0]
                 if t == tokenize.NEWLINE or (stop_at_NL and t == tokenize.NL):
                     # Stop before we try to pull a line we don't have yet
                     break
                 elif t == tokenize.ERRORTOKEN:
                     stop_at_NL = True
         except TokenError:
             # Multi-line statement - stop and try again with the next line
             self.reset_tokenizer()
             return None
         
         return self.output(tokens)
     
     def output(self, tokens):
         self.buf.clear()
         self.reset_tokenizer()
         return untokenize(self.func(tokens)).rstrip('\n')
     
     def reset(self):
         l = ''.join(self.buf)
         self.buf.clear()
         self.reset_tokenizer()
         if l:
             return l.rstrip('\n')
 
 class assemble_python_lines(TokenInputTransformer):
     def __init__(self):
-        super(assemble_python_lines, self).__init__(None)
+        super().__init__(None)
     
     def output(self, tokens):
         return self.reset()
 
 @CoroutineInputTransformer.wrap
 def assemble_logical_lines():
     r"""Join lines following explicit line continuations (\)"""
     line = ''
     while True:
         line = (yield line)
         if not line or line.isspace():
             continue
         
         parts = []
         while line is not None:
             if line.endswith('\\') and (not has_comment(line)):
                 parts.append(line[:-1])
                 line = (yield None) # Get another line
             else:
                 parts.append(line)
                 break
         
         # Output
         line = ''.join(parts)
 
 # Utilities
 def _make_help_call(target: str, esc: str, lspace: str) -> str:
     """Prepares a pinfo(2)/psearch call from a target name and the escape
     (i.e. ? or ??)"""
     method  = 'pinfo2' if esc == '??' \
                 else 'psearch' if '*' in target \
                 else 'pinfo'
     arg = " ".join([method, target])
     #Prepare arguments for get_ipython().run_line_magic(magic_name, magic_args)
     t_magic_name, _, t_magic_arg_s = arg.partition(' ')
     t_magic_name = t_magic_name.lstrip(ESC_MAGIC)
     return "%sget_ipython().run_line_magic(%r, %r)" % (
         lspace,
         t_magic_name,
         t_magic_arg_s,
     )
 
 
 # These define the transformations for the different escape characters.
 def _tr_system(line_info: LineInfo):
     "Translate lines escaped with: !"
     cmd = line_info.line.lstrip().lstrip(ESC_SHELL)
     return '%sget_ipython().system(%r)' % (line_info.pre, cmd)
 
 
 def _tr_system2(line_info: LineInfo):
     "Translate lines escaped with: !!"
     cmd = line_info.line.lstrip()[2:]
     return '%sget_ipython().getoutput(%r)' % (line_info.pre, cmd)
 
 
 def _tr_help(line_info: LineInfo):
     "Translate lines escaped with: ?/??"
     # A naked help line should just fire the intro help screen
     if not line_info.line[1:]:
         return 'get_ipython().show_usage()'
 
     return _make_help_call(line_info.ifun, line_info.esc, line_info.pre)
 
 
 def _tr_magic(line_info: LineInfo):
     "Translate lines escaped with: %"
     tpl = '%sget_ipython().run_line_magic(%r, %r)'
     if line_info.line.startswith(ESC_MAGIC2):
         return line_info.line
     cmd = ' '.join([line_info.ifun, line_info.the_rest]).strip()
     #Prepare arguments for get_ipython().run_line_magic(magic_name, magic_args)
     t_magic_name, _, t_magic_arg_s = cmd.partition(' ')
     t_magic_name = t_magic_name.lstrip(ESC_MAGIC)
     return tpl % (line_info.pre, t_magic_name, t_magic_arg_s)
 
 
 def _tr_quote(line_info: LineInfo):
     "Translate lines escaped with: ,"
     return '%s%s("%s")' % (line_info.pre, line_info.ifun,
                          '", "'.join(line_info.the_rest.split()) )
 
 
 def _tr_quote2(line_info: LineInfo):
     "Translate lines escaped with: ;"
     return '%s%s("%s")' % (line_info.pre, line_info.ifun,
                            line_info.the_rest)
 
 
 def _tr_paren(line_info: LineInfo):
     "Translate lines escaped with: /"
     return '%s%s(%s)' % (line_info.pre, line_info.ifun,
                          ", ".join(line_info.the_rest.split()))
 
 tr = { ESC_SHELL  : _tr_system,
        ESC_SH_CAP : _tr_system2,
        ESC_HELP   : _tr_help,
        ESC_HELP2  : _tr_help,
        ESC_MAGIC  : _tr_magic,
        ESC_QUOTE  : _tr_quote,
        ESC_QUOTE2 : _tr_quote2,
        ESC_PAREN  : _tr_paren }
 
 @StatelessInputTransformer.wrap
 def escaped_commands(line: str):
     """Transform escaped commands - %magic, !system, ?help + various autocalls."""
     if not line or line.isspace():
         return line
     lineinf = LineInfo(line)
     if lineinf.esc not in tr:
         return line
     
     return tr[lineinf.esc](lineinf)
 
 _initial_space_re = re.compile(r'\s*')
 
 _help_end_re = re.compile(r"""(%{0,2}
                               (?!\d)[\w*]+            # Variable name
                               (\.(?!\d)[\w*]+)*       # .etc.etc
                               )
                               (\?\??)$                # ? or ??
                               """,
                               re.VERBOSE)
 
 # Extra pseudotokens for multiline strings and data structures
 _MULTILINE_STRING = object()
 _MULTILINE_STRUCTURE = object()
 
 def _line_tokens(line):
     """Helper for has_comment and ends_in_comment_or_string."""
     readline = StringIO(line).readline
     toktypes = set()
     try:
         for t in tokenutil.generate_tokens_catch_errors(readline):
             toktypes.add(t[0])
     except TokenError as e:
         # There are only two cases where a TokenError is raised.
         if 'multi-line string' in e.args[0]:
             toktypes.add(_MULTILINE_STRING)
         else:
             toktypes.add(_MULTILINE_STRUCTURE)
     return toktypes
 
 def has_comment(src):
     """Indicate whether an input line has (i.e. ends in, or is) a comment.
 
     This uses tokenize, so it can distinguish comments from # inside strings.
 
     Parameters
     ----------
     src : string
         A single line input string.
 
     Returns
     -------
     comment : bool
         True if source has a comment.
     """
     return (tokenize.COMMENT in _line_tokens(src))
 
 def ends_in_comment_or_string(src):
     """Indicates whether or not an input line ends in a comment or within
     a multiline string.
 
     Parameters
     ----------
     src : string
         A single line input string.
 
     Returns
     -------
     comment : bool
         True if source ends in a comment or multiline string.
     """
     toktypes = _line_tokens(src)
     return (tokenize.COMMENT in toktypes) or (_MULTILINE_STRING in toktypes)
         
 
 @StatelessInputTransformer.wrap
 def help_end(line: str):
     """Translate lines with ?/?? at the end"""
     m = _help_end_re.search(line)
     if m is None or ends_in_comment_or_string(line):
         return line
     target = m.group(1)
     esc = m.group(3)
     match = _initial_space_re.match(line)
     assert match is not None
     lspace = match.group(0)
 
     return _make_help_call(target, esc, lspace)
 
 
 @CoroutineInputTransformer.wrap
 def cellmagic(end_on_blank_line: bool = False):
     """Captures & transforms cell magics.
 
     After a cell magic is started, this stores up any lines it gets until it is
     reset (sent None).
     """
     tpl = 'get_ipython().run_cell_magic(%r, %r, %r)'
     cellmagic_help_re = re.compile(r'%%\w+\?')
     line = ''
     while True:
         line = (yield line)
         # consume leading empty lines
         while not line:
             line = (yield line)
         
         if not line.startswith(ESC_MAGIC2):
             # This isn't a cell magic, idle waiting for reset then start over
             while line is not None:
                 line = (yield line)
             continue
         
         if cellmagic_help_re.match(line):
             # This case will be handled by help_end
             continue
         
         first = line
         body = []
         line = (yield None)
         while (line is not None) and \
                                 ((line.strip() != '') or not end_on_blank_line):
             body.append(line)
             line = (yield None)
         
         # Output
         magic_name, _, first = first.partition(' ')
         magic_name = magic_name.lstrip(ESC_MAGIC2)
         line = tpl % (magic_name, first, u'\n'.join(body))
 
 
 def _strip_prompts(prompt_re, initial_re=None, turnoff_re=None):
     """Remove matching input prompts from a block of input.
 
     Parameters
     ----------
     prompt_re : regular expression
         A regular expression matching any input prompt (including continuation)
     initial_re : regular expression, optional
         A regular expression matching only the initial prompt, but not continuation.
         If no initial expression is given, prompt_re will be used everywhere.
         Used mainly for plain Python prompts, where the continuation prompt
         ``...`` is a valid Python expression in Python 3, so shouldn't be stripped.
 
     Notes
     -----
     If `initial_re` and `prompt_re differ`,
     only `initial_re` will be tested against the first line.
     If any prompt is found on the first two lines,
     prompts will be stripped from the rest of the block.
     """
     if initial_re is None:
         initial_re = prompt_re
     line = ''
     while True:
         line = (yield line)
         
         # First line of cell
         if line is None:
             continue
         out, n1 = initial_re.subn('', line, count=1)
         if turnoff_re and not n1:
             if turnoff_re.match(line):
                 # We're in e.g. a cell magic; disable this transformer for
                 # the rest of the cell.
                 while line is not None:
                     line = (yield line)
                 continue
 
         line = (yield out)
         
         if line is None:
             continue
         # check for any prompt on the second line of the cell,
         # because people often copy from just after the first prompt,
         # so we might not see it in the first line.
         out, n2 = prompt_re.subn('', line, count=1)
         line = (yield out)
         
         if n1 or n2:
             # Found a prompt in the first two lines - check for it in
             # the rest of the cell as well.
             while line is not None:
                 line = (yield prompt_re.sub('', line, count=1))
         
         else:
             # Prompts not in input - wait for reset
             while line is not None:
                 line = (yield line)
 
 @CoroutineInputTransformer.wrap
 def classic_prompt():
     """Strip the >>>/... prompts of the Python interactive shell."""
     # FIXME: non-capturing version (?:...) usable?
     prompt_re = re.compile(r'^(>>>|\.\.\.)( |$)')
     initial_re = re.compile(r'^>>>( |$)')
     # Any %magic/!system is IPython syntax, so we needn't look for >>> prompts
     turnoff_re = re.compile(r'^[%!]')
     return _strip_prompts(prompt_re, initial_re, turnoff_re)
 
 @CoroutineInputTransformer.wrap
 def ipy_prompt():
     """Strip IPython's In [1]:/...: prompts."""
     # FIXME: non-capturing version (?:...) usable?
     prompt_re = re.compile(r'^(In \[\d+\]: |\s*\.{3,}: ?)')
     # Disable prompt stripping inside cell magics
     turnoff_re = re.compile(r'^%%')
     return _strip_prompts(prompt_re, turnoff_re=turnoff_re)
 
 
 @CoroutineInputTransformer.wrap
 def leading_indent():
     """Remove leading indentation.
 
     If the first line starts with a spaces or tabs, the same whitespace will be
     removed from each following line until it is reset.
     """
     space_re = re.compile(r'^[ \t]+')
     line = ''
     while True:
         line = (yield line)
         
         if line is None:
             continue
         
         m = space_re.match(line)
         if m:
             space = m.group(0)
             while line is not None:
                 if line.startswith(space):
                     line = line[len(space):]
                 line = (yield line)
         else:
             # No leading spaces - wait for reset
             while line is not None:
                 line = (yield line)
 
 
 _assign_pat = \
 r'''(?P<lhs>(\s*)
     ([\w\.]+)                # Initial identifier
     (\s*,\s*
         \*?[\w\.]+)*         # Further identifiers for unpacking
     \s*?,?                   # Trailing comma
     )
     \s*=\s*
 '''
 
 assign_system_re = re.compile(r'{}!\s*(?P<cmd>.*)'.format(_assign_pat), re.VERBOSE)
 assign_system_template = '%s = get_ipython().getoutput(%r)'
 @StatelessInputTransformer.wrap
 def assign_from_system(line):
     """Transform assignment from system commands (e.g. files = !ls)"""
     m = assign_system_re.match(line)
     if m is None:
         return line
     
     return assign_system_template % m.group('lhs', 'cmd')
 
 assign_magic_re = re.compile(r'{}%\s*(?P<cmd>.*)'.format(_assign_pat), re.VERBOSE)
 assign_magic_template = '%s = get_ipython().run_line_magic(%r, %r)'
 @StatelessInputTransformer.wrap
 def assign_from_magic(line):
     """Transform assignment from magic commands (e.g. a = %who_ls)"""
     m = assign_magic_re.match(line)
     if m is None:
         return line
     #Prepare arguments for get_ipython().run_line_magic(magic_name, magic_args)
     m_lhs, m_cmd = m.group('lhs', 'cmd')
     t_magic_name, _, t_magic_arg_s = m_cmd.partition(' ')
     t_magic_name = t_magic_name.lstrip(ESC_MAGIC)
     return assign_magic_template % (m_lhs, t_magic_name, t_magic_arg_s)

docs/source/config/inputtransforms.rst

@@ -1,90 +1,90
 
 ===========================
 Custom input transformation
 ===========================
 
 IPython extends Python syntax to allow things like magic commands, and help with
 the ``?`` syntax. There are several ways to customise how the user's input is
 processed into Python code to be executed.
 
 These hooks are mainly for other projects using IPython as the core of their
 interactive interface. Using them carelessly can easily break IPython!
 
 String based transformations
 ============================
 
-.. currentmodule:: IPython.core.inputtransforms
+.. currentmodule:: IPython.core.inputtransformers2
 
 When the user enters code, it is first processed as a string. By the
 end of this stage, it must be valid Python syntax.
 
 .. versionchanged:: 7.0
 
    The API for string and token-based transformations has been completely
    redesigned. Any third party code extending input transformation will need to
    be rewritten. The new API is, hopefully, simpler.
 
 String based transformations are functions which accept a list of strings:
 each string is a single line of the input cell, including its line ending.
 The transformation function should return output in the same structure.
 
 These transformations are in two groups, accessible as attributes of
 the :class:`~IPython.core.interactiveshell.InteractiveShell` instance.
 Each group is a list of transformation functions.
 
 * ``input_transformers_cleanup`` run first on input, to do things like stripping
   prompts and leading indents from copied code. It may not be possible at this
   stage to parse the input as valid Python code.
 * Then IPython runs its own transformations to handle its special syntax, like
   ``%magics`` and ``!system`` commands. This part does not expose extension
   points.
 * ``input_transformers_post`` run as the last step, to do things like converting
   float literals into decimal objects. These may attempt to parse the input as
   Python code.  
 
 These transformers may raise :exc:`SyntaxError` if the input code is invalid, but
 in most cases it is clearer to pass unrecognised code through unmodified and let
 Python's own parser decide whether it is valid.
 
 For example, imagine we want to obfuscate our code by reversing each line, so
 we'd write ``)5(f =+ a`` instead of ``a += f(5)``. Here's how we could swap it
 back the right way before IPython tries to run it::
 
     def reverse_line_chars(lines):
         new_lines = []
         for line in lines:
             chars = line[:-1]  # the newline needs to stay at the end
             new_lines.append(chars[::-1] + '\n')
         return new_lines
 
 To start using this::
 
     ip = get_ipython()
     ip.input_transformers_cleanup.append(reverse_line_chars)
 
 .. versionadded:: 7.17
 
     input_transformers can now have an attribute ``has_side_effects`` set to
     `True`, which will prevent the transformers from being ran when IPython is
     trying to guess whether the user input is complete. 
 
 
 
 AST transformations
 ===================
 
 After the code has been parsed as Python syntax, you can use Python's powerful
 *Abstract Syntax Tree* tools to modify it. Subclass :class:`ast.NodeTransformer`,
 and add an instance to ``shell.ast_transformers``.
 
 This example wraps integer literals in an ``Integer`` class, which is useful for
 mathematical frameworks that want to handle e.g. ``1/3`` as a precise fraction::
 
 
     class IntegerWrapper(ast.NodeTransformer):
         """Wraps all integers in a call to Integer()"""
         def visit_Num(self, node):
             if isinstance(node.value, int):
                 return ast.Call(func=ast.Name(id='Integer', ctx=ast.Load()),
                                 args=[node], keywords=[])
             return node