← Back
Editing: inputsplitter.py
"""DEPRECATED: Input handling and transformation machinery. This module was deprecated in IPython 7.0, in favour of inputtransformer2. The first class in this module, :class:`InputSplitter`, is designed to tell when input from a line-oriented frontend is complete and should be executed, and when the user should be prompted for another line of code instead. The name 'input splitter' is largely for historical reasons. A companion, :class:`IPythonInputSplitter`, provides the same functionality but with full support for the extended IPython syntax (magics, system calls, etc). The code to actually do these transformations is in :mod:`IPython.core.inputtransformer`. :class:`IPythonInputSplitter` feeds the raw code to the transformers in order and stores the results. For more details, see the class docstrings below. """ from warnings import warn warn('IPython.core.inputsplitter is deprecated since IPython 7 in favor of `IPython.core.inputtransformer2`', DeprecationWarning) # Copyright (c) IPython Development Team. # Distributed under the terms of the Modified BSD License. import ast import codeop import io import re import sys import tokenize import warnings from IPython.core.inputtransformer import (leading_indent, classic_prompt, ipy_prompt, cellmagic, assemble_logical_lines, help_end, escaped_commands, assign_from_magic, assign_from_system, assemble_python_lines, ) # These are available in this module for backwards compatibility. from IPython.core.inputtransformer import (ESC_SHELL, ESC_SH_CAP, ESC_HELP, ESC_HELP2, ESC_MAGIC, ESC_MAGIC2, ESC_QUOTE, ESC_QUOTE2, ESC_PAREN, ESC_SEQUENCES) #----------------------------------------------------------------------------- # Utilities #----------------------------------------------------------------------------- # FIXME: These are general-purpose utilities that later can be moved to the # general ward. Kept here for now because we're being very strict about test # coverage with this code, and this lets us ensure that we keep 100% coverage # while developing. # compiled regexps for autoindent management dedent_re = re.compile('|'.join([ r'^\s+raise(\s.*)?$', # raise statement (+ space + other stuff, maybe) r'^\s+raise\([^\)]*\).*$', # wacky raise with immediate open paren r'^\s+return(\s.*)?$', # normal return (+ space + other stuff, maybe) r'^\s+return\([^\)]*\).*$', # wacky return with immediate open paren r'^\s+pass\s*$', # pass (optionally followed by trailing spaces) r'^\s+break\s*$', # break (optionally followed by trailing spaces) r'^\s+continue\s*$', # continue (optionally followed by trailing spaces) ])) ini_spaces_re = re.compile(r'^([ \t\r\f\v]+)') # regexp to match pure comment lines so we don't accidentally insert 'if 1:' # before pure comments comment_line_re = re.compile(r'^\s*\#') def num_ini_spaces(s): """Return the number of initial spaces in a string. Note that tabs are counted as a single space. For now, we do *not* support mixing of tabs and spaces in the user's input. Parameters ---------- s : string Returns ------- n : int """ ini_spaces = ini_spaces_re.match(s) if ini_spaces: return ini_spaces.end() else: return 0 # Fake token types for partial_tokenize: INCOMPLETE_STRING = tokenize.N_TOKENS IN_MULTILINE_STATEMENT = tokenize.N_TOKENS + 1 # The 2 classes below have the same API as TokenInfo, but don't try to look up # a token type name that they won't find. class IncompleteString: type = exact_type = INCOMPLETE_STRING def __init__(self, s, start, end, line): self.s = s self.start = start self.end = end self.line = line class InMultilineStatement: type = exact_type = IN_MULTILINE_STATEMENT def __init__(self, pos, line): self.s = '' self.start = self.end = pos self.line = line def partial_tokens(s): """Iterate over tokens from a possibly-incomplete string of code. This adds two special token types: INCOMPLETE_STRING and IN_MULTILINE_STATEMENT. These can only occur as the last token yielded, and represent the two main ways for code to be incomplete. """ readline = io.StringIO(s).readline token = tokenize.TokenInfo(tokenize.NEWLINE, '', (1, 0), (1, 0), '') try: for token in tokenize.generate_tokens(readline): yield token except tokenize.TokenError as e: # catch EOF error lines = s.splitlines(keepends=True) end = len(lines), len(lines[-1]) if 'multi-line string' in e.args[0]: l, c = start = token.end s = lines[l-1][c:] + ''.join(lines[l:]) yield IncompleteString(s, start, end, lines[-1]) elif 'multi-line statement' in e.args[0]: yield InMultilineStatement(end, lines[-1]) else: raise def find_next_indent(code): """Find the number of spaces for the next line of indentation""" tokens = list(partial_tokens(code)) if tokens[-1].type == tokenize.ENDMARKER: tokens.pop() if not tokens: return 0 while (tokens[-1].type in {tokenize.DEDENT, tokenize.NEWLINE, tokenize.COMMENT}): tokens.pop() if tokens[-1].type == INCOMPLETE_STRING: # Inside a multiline string return 0 # Find the indents used before prev_indents = [0] def _add_indent(n): if n != prev_indents[-1]: prev_indents.append(n) tokiter = iter(tokens) for tok in tokiter: if tok.type in {tokenize.INDENT, tokenize.DEDENT}: _add_indent(tok.end[1]) elif (tok.type == tokenize.NL): try: _add_indent(next(tokiter).start[1]) except StopIteration: break last_indent = prev_indents.pop() # If we've just opened a multiline statement (e.g. 'a = ['), indent more if tokens[-1].type == IN_MULTILINE_STATEMENT: if tokens[-2].exact_type in {tokenize.LPAR, tokenize.LSQB, tokenize.LBRACE}: return last_indent + 4 return last_indent if tokens[-1].exact_type == tokenize.COLON: # Line ends with colon - indent return last_indent + 4 if last_indent: # Examine the last line for dedent cues - statements like return or # raise which normally end a block of code. last_line_starts = 0 for i, tok in enumerate(tokens): if tok.type == tokenize.NEWLINE: last_line_starts = i + 1 last_line_tokens = tokens[last_line_starts:] names = [t.string for t in last_line_tokens if t.type == tokenize.NAME] if names and names[0] in {'raise', 'return', 'pass', 'break', 'continue'}: # Find the most recent indentation less than the current level for indent in reversed(prev_indents): if indent < last_indent: return indent return last_indent def last_blank(src): """Determine if the input source ends in a blank. A blank is either a newline or a line consisting of whitespace. Parameters ---------- src : string A single or multiline string. """ if not src: return False ll = src.splitlines()[-1] return (ll == '') or ll.isspace() last_two_blanks_re = re.compile(r'\n\s*\n\s*$', re.MULTILINE) last_two_blanks_re2 = re.compile(r'.+\n\s*\n\s+$', re.MULTILINE) def last_two_blanks(src): """Determine if the input source ends in two blanks. A blank is either a newline or a line consisting of whitespace. Parameters ---------- src : string A single or multiline string. """ if not src: return False # The logic here is tricky: I couldn't get a regexp to work and pass all # the tests, so I took a different approach: split the source by lines, # grab the last two and prepend '###\n' as a stand-in for whatever was in # the body before the last two lines. Then, with that structure, it's # possible to analyze with two regexps. Not the most elegant solution, but # it works. If anyone tries to change this logic, make sure to validate # the whole test suite first! new_src = '\n'.join(['###\n'] + src.splitlines()[-2:]) return (bool(last_two_blanks_re.match(new_src)) or bool(last_two_blanks_re2.match(new_src)) ) def remove_comments(src): """Remove all comments from input source. Note: comments are NOT recognized inside of strings! Parameters ---------- src : string A single or multiline input string. Returns ------- String with all Python comments removed. """ return re.sub('#.*', '', src) def get_input_encoding(): """Return the default standard input encoding. If sys.stdin has no encoding, 'ascii' is returned.""" # There are strange environments for which sys.stdin.encoding is None. We # ensure that a valid encoding is returned. encoding = getattr(sys.stdin, 'encoding', None) if encoding is None: encoding = 'ascii' return encoding #----------------------------------------------------------------------------- # Classes and functions for normal Python syntax handling #----------------------------------------------------------------------------- class InputSplitter(object): r"""An object that can accumulate lines of Python source before execution. This object is designed to be fed python source line-by-line, using :meth:`push`. It will return on each push whether the currently pushed code could be executed already. In addition, it provides a method called :meth:`push_accepts_more` that can be used to query whether more input can be pushed into a single interactive block. This is a simple example of how an interactive terminal-based client can use this tool:: isp = InputSplitter() while isp.push_accepts_more(): indent = ' '*isp.indent_spaces prompt = '>>> ' + indent line = indent + raw_input(prompt) isp.push(line) print 'Input source was:\n', isp.source_reset(), """ # A cache for storing the current indentation # The first value stores the most recently processed source input # The second value is the number of spaces for the current indentation # If self.source matches the first value, the second value is a valid # current indentation. Otherwise, the cache is invalid and the indentation # must be recalculated. _indent_spaces_cache = None, None # String, indicating the default input encoding. It is computed by default # at initialization time via get_input_encoding(), but it can be reset by a # client with specific knowledge of the encoding. encoding = '' # String where the current full source input is stored, properly encoded. # Reading this attribute is the normal way of querying the currently pushed # source code, that has been properly encoded. source = '' # Code object corresponding to the current source. It is automatically # synced to the source, so it can be queried at any time to obtain the code # object; it will be None if the source doesn't compile to valid Python. code = None # Private attributes # List with lines of input accumulated so far _buffer = None # Command compiler _compile = None # Boolean indicating whether the current block is complete _is_complete = None # Boolean indicating whether the current block has an unrecoverable syntax error _is_invalid = False def __init__(self): """Create a new InputSplitter instance. """ self._buffer = [] self._compile = codeop.CommandCompiler() self.encoding = get_input_encoding() def reset(self): """Reset the input buffer and associated state.""" self._buffer[:] = [] self.source = '' self.code = None self._is_complete = False self._is_invalid = False def source_reset(self): """Return the input source and perform a full reset. """ out = self.source self.reset() return out def check_complete(self, source): """Return whether a block of code is ready to execute, or should be continued This is a non-stateful API, and will reset the state of this InputSplitter. Parameters ---------- source : string Python input code, which can be multiline. Returns ------- status : str One of 'complete', 'incomplete', or 'invalid' if source is not a prefix of valid code. indent_spaces : int or None The number of spaces by which to indent the next line of code. If status is not 'incomplete', this is None. """ self.reset() try: self.push(source) except SyntaxError: # Transformers in IPythonInputSplitter can raise SyntaxError, # which push() will not catch. return 'invalid', None else: if self._is_invalid: return 'invalid', None elif self.push_accepts_more(): return 'incomplete', self.get_indent_spaces() else: return 'complete', None finally: self.reset() def push(self, lines:str) -> bool: """Push one or more lines of input. This stores the given lines and returns a status code indicating whether the code forms a complete Python block or not. Any exceptions generated in compilation are swallowed, but if an exception was produced, the method returns True. Parameters ---------- lines : string One or more lines of Python input. Returns ------- is_complete : boolean True if the current input source (the result of the current input plus prior inputs) forms a complete Python execution block. Note that this value is also stored as a private attribute (``_is_complete``), so it can be queried at any time. """ assert isinstance(lines, str) self._store(lines) source = self.source # Before calling _compile(), reset the code object to None so that if an # exception is raised in compilation, we don't mislead by having # inconsistent code/source attributes. self.code, self._is_complete = None, None self._is_invalid = False # Honor termination lines properly if source.endswith('\\\n'): return False try: with warnings.catch_warnings(): warnings.simplefilter('error', SyntaxWarning) self.code = self._compile(source, symbol="exec") # Invalid syntax can produce any of a number of different errors from # inside the compiler, so we have to catch them all. Syntax errors # immediately produce a 'ready' block, so the invalid Python can be # sent to the kernel for evaluation with possible ipython # special-syntax conversion. except (SyntaxError, OverflowError, ValueError, TypeError, MemoryError, SyntaxWarning): self._is_complete = True self._is_invalid = True else: # Compilation didn't produce any exceptions (though it may not have # given a complete code object) self._is_complete = self.code is not None return self._is_complete def push_accepts_more(self): """Return whether a block of interactive input can accept more input. This method is meant to be used by line-oriented frontends, who need to guess whether a block is complete or not based solely on prior and current input lines. The InputSplitter considers it has a complete interactive block and will not accept more input when either: * A SyntaxError is raised * The code is complete and consists of a single line or a single non-compound statement * The code is complete and has a blank line at the end If the current input produces a syntax error, this method immediately returns False but does *not* raise the syntax error exception, as typically clients will want to send invalid syntax to an execution backend which might convert the invalid syntax into valid Python via one of the dynamic IPython mechanisms. """ # With incomplete input, unconditionally accept more # A syntax error also sets _is_complete to True - see push() if not self._is_complete: #print("Not complete") # debug return True # The user can make any (complete) input execute by leaving a blank line last_line = self.source.splitlines()[-1] if (not last_line) or last_line.isspace(): #print("Blank line") # debug return False # If there's just a single line or AST node, and we're flush left, as is # the case after a simple statement such as 'a=1', we want to execute it # straight away. if self.get_indent_spaces() == 0: if len(self.source.splitlines()) <= 1: return False try: code_ast = ast.parse(u''.join(self._buffer)) except Exception: #print("Can't parse AST") # debug return False else: if len(code_ast.body) == 1 and \ not hasattr(code_ast.body[0], 'body'): #print("Simple statement") # debug return False # General fallback - accept more code return True def get_indent_spaces(self): sourcefor, n = self._indent_spaces_cache if sourcefor == self.source: return n # self.source always has a trailing newline n = find_next_indent(self.source[:-1]) self._indent_spaces_cache = (self.source, n) return n # Backwards compatibility. I think all code that used .indent_spaces was # inside IPython, but we can leave this here until IPython 7 in case any # other modules are using it. -TK, November 2017 indent_spaces = property(get_indent_spaces) def _store(self, lines, buffer=None, store='source'): """Store one or more lines of input. If input lines are not newline-terminated, a newline is automatically appended.""" if buffer is None: buffer = self._buffer if lines.endswith('\n'): buffer.append(lines) else: buffer.append(lines+'\n') setattr(self, store, self._set_source(buffer)) def _set_source(self, buffer): return u''.join(buffer) class IPythonInputSplitter(InputSplitter): """An input splitter that recognizes all of IPython's special syntax.""" # String with raw, untransformed input. source_raw = '' # Flag to track when a transformer has stored input that it hasn't given # back yet. transformer_accumulating = False # Flag to track when assemble_python_lines has stored input that it hasn't # given back yet. within_python_line = False # Private attributes # List with lines of raw input accumulated so far. _buffer_raw = None def __init__(self, line_input_checker=True, physical_line_transforms=None, logical_line_transforms=None, python_line_transforms=None): super(IPythonInputSplitter, self).__init__() self._buffer_raw = [] self._validate = True if physical_line_transforms is not None: self.physical_line_transforms = physical_line_transforms else: self.physical_line_transforms = [ leading_indent(), classic_prompt(), ipy_prompt(), cellmagic(end_on_blank_line=line_input_checker), ] self.assemble_logical_lines = assemble_logical_lines() if logical_line_transforms is not None: self.logical_line_transforms = logical_line_transforms else: self.logical_line_transforms = [ help_end(), escaped_commands(), assign_from_magic(), assign_from_system(), ] self.assemble_python_lines = assemble_python_lines() if python_line_transforms is not None: self.python_line_transforms = python_line_transforms else: # We don't use any of these at present self.python_line_transforms = [] @property def transforms(self): "Quick access to all transformers." return self.physical_line_transforms + \ [self.assemble_logical_lines] + self.logical_line_transforms + \ [self.assemble_python_lines] + self.python_line_transforms @property def transforms_in_use(self): """Transformers, excluding logical line transformers if we're in a Python line.""" t = self.physical_line_transforms[:] if not self.within_python_line: t += [self.assemble_logical_lines] + self.logical_line_transforms return t + [self.assemble_python_lines] + self.python_line_transforms def reset(self): """Reset the input buffer and associated state.""" super(IPythonInputSplitter, self).reset() self._buffer_raw[:] = [] self.source_raw = '' self.transformer_accumulating = False self.within_python_line = False for t in self.transforms: try: t.reset() except SyntaxError: # Nothing that calls reset() expects to handle transformer # errors pass def flush_transformers(self): def _flush(transform, outs): """yield transformed lines always strings, never None transform: the current transform outs: an iterable of previously transformed inputs. Each may be multiline, which will be passed one line at a time to transform. """ for out in outs: for line in out.splitlines(): # push one line at a time tmp = transform.push(line) if tmp is not None: yield tmp # reset the transform tmp = transform.reset() if tmp is not None: yield tmp out = [] for t in self.transforms_in_use: out = _flush(t, out) out = list(out) if out: self._store('\n'.join(out)) def raw_reset(self): """Return raw input only and perform a full reset. """ out = self.source_raw self.reset() return out def source_reset(self): try: self.flush_transformers() return self.source finally: self.reset() def push_accepts_more(self): if self.transformer_accumulating: return True else: return super(IPythonInputSplitter, self).push_accepts_more() def transform_cell(self, cell): """Process and translate a cell of input. """ self.reset() try: self.push(cell) self.flush_transformers() return self.source finally: self.reset() def push(self, lines:str) -> bool: """Push one or more lines of IPython input. This stores the given lines and returns a status code indicating whether the code forms a complete Python block or not, after processing all input lines for special IPython syntax. Any exceptions generated in compilation are swallowed, but if an exception was produced, the method returns True. Parameters ---------- lines : string One or more lines of Python input. Returns ------- is_complete : boolean True if the current input source (the result of the current input plus prior inputs) forms a complete Python execution block. Note that this value is also stored as a private attribute (_is_complete), so it can be queried at any time. """ assert isinstance(lines, str) # We must ensure all input is pure unicode # ''.splitlines() --> [], but we need to push the empty line to transformers lines_list = lines.splitlines() if not lines_list: lines_list = [''] # Store raw source before applying any transformations to it. Note # that this must be done *after* the reset() call that would otherwise # flush the buffer. self._store(lines, self._buffer_raw, 'source_raw') transformed_lines_list = [] for line in lines_list: transformed = self._transform_line(line) if transformed is not None: transformed_lines_list.append(transformed) if transformed_lines_list: transformed_lines = '\n'.join(transformed_lines_list) return super(IPythonInputSplitter, self).push(transformed_lines) else: # Got nothing back from transformers - they must be waiting for # more input. return False def _transform_line(self, line): """Push a line of input code through the various transformers. Returns any output from the transformers, or None if a transformer is accumulating lines. Sets self.transformer_accumulating as a side effect. """ def _accumulating(dbg): #print(dbg) self.transformer_accumulating = True return None for transformer in self.physical_line_transforms: line = transformer.push(line) if line is None: return _accumulating(transformer) if not self.within_python_line: line = self.assemble_logical_lines.push(line) if line is None: return _accumulating('acc logical line') for transformer in self.logical_line_transforms: line = transformer.push(line) if line is None: return _accumulating(transformer) line = self.assemble_python_lines.push(line) if line is None: self.within_python_line = True return _accumulating('acc python line') else: self.within_python_line = False for transformer in self.python_line_transforms: line = transformer.push(line) if line is None: return _accumulating(transformer) #print("transformers clear") #debug self.transformer_accumulating = False return line
Save File
Cancel