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inputtransformer.py
482 lines | 15.3 KiB | text/x-python | PythonLexer
import abc
import functools
import re
from StringIO import StringIO
from IPython.core.splitinput import LineInfo
from IPython.utils import tokenize2
from IPython.utils.openpy import cookie_comment_re
from IPython.utils.tokenize2 import generate_tokens, untokenize, TokenError
#-----------------------------------------------------------------------------
# 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(object):
"""Abstract base class for line-based input transformers."""
__metaclass__ = abc.ABCMeta
@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.
"""
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)
return transformer_factory
class StatelessInputTransformer(InputTransformer):
"""Wrapper for a stateless input transformer implemented as a function."""
def __init__(self, func):
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
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):
self.func = func
self.current_line = ""
self.line_used = False
self.reset_tokenizer()
def reset_tokenizer(self):
self.tokenizer = generate_tokens(self.get_line)
def get_line(self):
if self.line_used:
raise TokenError
self.line_used = True
return self.current_line
def push(self, line):
self.current_line += line + "\n"
if self.current_line.isspace():
return self.reset()
self.line_used = False
tokens = []
stop_at_NL = False
try:
for intok in self.tokenizer:
tokens.append(intok)
t = intok[0]
if t == tokenize2.NEWLINE or (stop_at_NL and t == tokenize2.NL):
# Stop before we try to pull a line we don't have yet
break
elif t == tokenize2.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.current_line = ""
self.reset_tokenizer()
return untokenize(self.func(tokens)).rstrip('\n')
def reset(self):
l = self.current_line
self.current_line = ""
self.reset_tokenizer()
if l:
return l.rstrip('\n')
class assemble_python_lines(TokenInputTransformer):
def __init__(self):
super(assemble_python_lines, self).__init__(None)
def output(self, tokens):
return self.reset()
@CoroutineInputTransformer.wrap
def assemble_logical_lines():
"""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, esc, lspace, next_input=None):
"""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])
if next_input is None:
return '%sget_ipython().magic(%r)' % (lspace, arg)
else:
return '%sget_ipython().set_next_input(%r);get_ipython().magic(%r)' % \
(lspace, next_input, arg)
# These define the transformations for the different escape characters.
def _tr_system(line_info):
"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):
"Translate lines escaped with: !!"
cmd = line_info.line.lstrip()[2:]
return '%sget_ipython().getoutput(%r)' % (line_info.pre, cmd)
def _tr_help(line_info):
"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):
"Translate lines escaped with: %"
tpl = '%sget_ipython().magic(%r)'
if line_info.line.startswith(ESC_MAGIC2):
return line_info.line
cmd = ' '.join([line_info.ifun, line_info.the_rest]).strip()
return tpl % (line_info.pre, cmd)
def _tr_quote(line_info):
"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):
"Translate lines escaped with: ;"
return '%s%s("%s")' % (line_info.pre, line_info.ifun,
line_info.the_rest)
def _tr_paren(line_info):
"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):
"""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}
[a-zA-Z_*][\w*]* # Variable name
(\.[a-zA-Z_*][\w*]*)* # .etc.etc
)
(\?\??)$ # ? or ??
""",
re.VERBOSE)
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.
"""
readline = StringIO(src).readline
toktypes = set()
try:
for t in generate_tokens(readline):
toktypes.add(t[0])
except TokenError:
pass
return(tokenize2.COMMENT in toktypes)
@StatelessInputTransformer.wrap
def help_end(line):
"""Translate lines with ?/?? at the end"""
m = _help_end_re.search(line)
if m is None or has_comment(line):
return line
target = m.group(1)
esc = m.group(3)
lspace = _initial_space_re.match(line).group(0)
# If we're mid-command, put it back on the next prompt for the user.
next_input = line.rstrip('?') if line.strip() != m.group(0) else None
return _make_help_call(target, esc, lspace, next_input)
@CoroutineInputTransformer.wrap
def cellmagic(end_on_blank_line=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('%%\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):
"""Remove matching input prompts from a block of input."""
line = ''
while True:
line = (yield line)
# First line of cell
if line is None:
continue
out, n1 = prompt_re.subn('', line, count=1)
line = (yield out)
# Second line of cell, because people often copy from just after the
# first prompt, so we might not see it in the first line.
if line is None:
continue
out, n2 = prompt_re.subn('', line, count=1)
line = (yield out)
if n1 or n2:
# Found the input 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'^(>>> ?|\.\.\. ?)')
return _strip_prompts(prompt_re)
@CoroutineInputTransformer.wrap
def ipy_prompt():
"""Strip IPython's In [1]:/...: prompts."""
# FIXME: non-capturing version (?:...) usable?
# FIXME: r'^(In \[\d+\]: | {3}\.{3,}: )' clearer?
prompt_re = re.compile(r'^(In \[\d+\]: |\ \ \ \.\.\.+: )')
return _strip_prompts(prompt_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)
@CoroutineInputTransformer.wrap
def strip_encoding_cookie():
"""Remove encoding comment if found in first two lines
If the first or second line has the `# coding: utf-8` comment,
it will be removed.
"""
line = ''
while True:
line = (yield line)
# check comment on first two lines
for i in range(2):
if line is None:
break
if cookie_comment_re.match(line):
line = (yield "")
else:
line = (yield line)
# no-op on the rest of the cell
while line is not None:
line = (yield line)
assign_system_re = re.compile(r'(?P<lhs>(\s*)([\w\.]+)((\s*,\s*[\w\.]+)*))'
r'\s*=\s*!\s*(?P<cmd>.*)')
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'(?P<lhs>(\s*)([\w\.]+)((\s*,\s*[\w\.]+)*))'
r'\s*=\s*%\s*(?P<cmd>.*)')
assign_magic_template = '%s = get_ipython().magic(%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
return assign_magic_template % m.group('lhs', 'cmd')