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1539 lines
56 KiB
1539 lines
56 KiB
# $Id: statemachine.py 8435 2019-12-12 13:04:57Z milde $
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# Author: David Goodger <goodger@python.org>
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# Copyright: This module has been placed in the public domain.
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"""
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A finite state machine specialized for regular-expression-based text filters,
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this module defines the following classes:
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- `StateMachine`, a state machine
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- `State`, a state superclass
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- `StateMachineWS`, a whitespace-sensitive version of `StateMachine`
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- `StateWS`, a state superclass for use with `StateMachineWS`
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- `SearchStateMachine`, uses `re.search()` instead of `re.match()`
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- `SearchStateMachineWS`, uses `re.search()` instead of `re.match()`
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- `ViewList`, extends standard Python lists.
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- `StringList`, string-specific ViewList.
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Exception classes:
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- `StateMachineError`
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- `UnknownStateError`
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- `DuplicateStateError`
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- `UnknownTransitionError`
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- `DuplicateTransitionError`
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- `TransitionPatternNotFound`
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- `TransitionMethodNotFound`
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- `UnexpectedIndentationError`
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- `TransitionCorrection`: Raised to switch to another transition.
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- `StateCorrection`: Raised to switch to another state & transition.
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Functions:
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- `string2lines()`: split a multi-line string into a list of one-line strings
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How To Use This Module
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======================
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(See the individual classes, methods, and attributes for details.)
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1. Import it: ``import statemachine`` or ``from statemachine import ...``.
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You will also need to ``import re``.
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2. Derive a subclass of `State` (or `StateWS`) for each state in your state
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machine::
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class MyState(statemachine.State):
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Within the state's class definition:
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a) Include a pattern for each transition, in `State.patterns`::
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patterns = {'atransition': r'pattern', ...}
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b) Include a list of initial transitions to be set up automatically, in
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`State.initial_transitions`::
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initial_transitions = ['atransition', ...]
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c) Define a method for each transition, with the same name as the
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transition pattern::
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def atransition(self, match, context, next_state):
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# do something
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result = [...] # a list
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return context, next_state, result
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# context, next_state may be altered
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Transition methods may raise an `EOFError` to cut processing short.
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d) You may wish to override the `State.bof()` and/or `State.eof()` implicit
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transition methods, which handle the beginning- and end-of-file.
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e) In order to handle nested processing, you may wish to override the
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attributes `State.nested_sm` and/or `State.nested_sm_kwargs`.
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If you are using `StateWS` as a base class, in order to handle nested
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indented blocks, you may wish to:
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- override the attributes `StateWS.indent_sm`,
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`StateWS.indent_sm_kwargs`, `StateWS.known_indent_sm`, and/or
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`StateWS.known_indent_sm_kwargs`;
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- override the `StateWS.blank()` method; and/or
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- override or extend the `StateWS.indent()`, `StateWS.known_indent()`,
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and/or `StateWS.firstknown_indent()` methods.
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3. Create a state machine object::
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sm = StateMachine(state_classes=[MyState, ...],
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initial_state='MyState')
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4. Obtain the input text, which needs to be converted into a tab-free list of
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one-line strings. For example, to read text from a file called
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'inputfile'::
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input_string = open('inputfile').read()
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input_lines = statemachine.string2lines(input_string)
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5. Run the state machine on the input text and collect the results, a list::
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results = sm.run(input_lines)
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6. Remove any lingering circular references::
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sm.unlink()
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"""
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from __future__ import print_function
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__docformat__ = 'restructuredtext'
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import sys
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import re
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import unicodedata
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from docutils import utils
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from docutils.utils.error_reporting import ErrorOutput
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if sys.version_info >= (3, 0):
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unicode = str # noqa
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class StateMachine(object):
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"""
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A finite state machine for text filters using regular expressions.
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The input is provided in the form of a list of one-line strings (no
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newlines). States are subclasses of the `State` class. Transitions consist
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of regular expression patterns and transition methods, and are defined in
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each state.
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The state machine is started with the `run()` method, which returns the
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results of processing in a list.
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"""
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def __init__(self, state_classes, initial_state, debug=False):
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"""
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Initialize a `StateMachine` object; add state objects.
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Parameters:
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- `state_classes`: a list of `State` (sub)classes.
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- `initial_state`: a string, the class name of the initial state.
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- `debug`: a boolean; produce verbose output if true (nonzero).
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"""
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self.input_lines = None
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"""`StringList` of input lines (without newlines).
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Filled by `self.run()`."""
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self.input_offset = 0
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"""Offset of `self.input_lines` from the beginning of the file."""
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self.line = None
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"""Current input line."""
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self.line_offset = -1
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"""Current input line offset from beginning of `self.input_lines`."""
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self.debug = debug
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"""Debugging mode on/off."""
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self.initial_state = initial_state
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"""The name of the initial state (key to `self.states`)."""
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self.current_state = initial_state
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"""The name of the current state (key to `self.states`)."""
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self.states = {}
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"""Mapping of {state_name: State_object}."""
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self.add_states(state_classes)
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self.observers = []
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"""List of bound methods or functions to call whenever the current
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line changes. Observers are called with one argument, ``self``.
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Cleared at the end of `run()`."""
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self._stderr = ErrorOutput()
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"""Wrapper around sys.stderr catching en-/decoding errors"""
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def unlink(self):
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"""Remove circular references to objects no longer required."""
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for state in self.states.values():
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state.unlink()
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self.states = None
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def run(self, input_lines, input_offset=0, context=None,
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input_source=None, initial_state=None):
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"""
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Run the state machine on `input_lines`. Return results (a list).
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Reset `self.line_offset` and `self.current_state`. Run the
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beginning-of-file transition. Input one line at a time and check for a
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matching transition. If a match is found, call the transition method
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and possibly change the state. Store the context returned by the
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transition method to be passed on to the next transition matched.
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Accumulate the results returned by the transition methods in a list.
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Run the end-of-file transition. Finally, return the accumulated
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results.
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Parameters:
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- `input_lines`: a list of strings without newlines, or `StringList`.
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- `input_offset`: the line offset of `input_lines` from the beginning
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of the file.
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- `context`: application-specific storage.
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- `input_source`: name or path of source of `input_lines`.
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- `initial_state`: name of initial state.
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"""
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self.runtime_init()
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if isinstance(input_lines, StringList):
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self.input_lines = input_lines
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else:
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self.input_lines = StringList(input_lines, source=input_source)
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self.input_offset = input_offset
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self.line_offset = -1
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self.current_state = initial_state or self.initial_state
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if self.debug:
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print((
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u'\nStateMachine.run: input_lines (line_offset=%s):\n| %s'
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% (self.line_offset, u'\n| '.join(self.input_lines))), file=self._stderr)
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transitions = None
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results = []
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state = self.get_state()
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try:
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if self.debug:
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print('\nStateMachine.run: bof transition', file=self._stderr)
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context, result = state.bof(context)
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results.extend(result)
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while True:
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try:
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try:
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self.next_line()
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if self.debug:
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source, offset = self.input_lines.info(
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self.line_offset)
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print((
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u'\nStateMachine.run: line (source=%r, '
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u'offset=%r):\n| %s'
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% (source, offset, self.line)), file=self._stderr)
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context, next_state, result = self.check_line(
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context, state, transitions)
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except EOFError:
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if self.debug:
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print((
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'\nStateMachine.run: %s.eof transition'
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% state.__class__.__name__), file=self._stderr)
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result = state.eof(context)
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results.extend(result)
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break
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else:
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results.extend(result)
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except TransitionCorrection as exception:
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self.previous_line() # back up for another try
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transitions = (exception.args[0],)
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if self.debug:
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print((
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'\nStateMachine.run: TransitionCorrection to '
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'state "%s", transition %s.'
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% (state.__class__.__name__, transitions[0])), file=self._stderr)
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continue
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except StateCorrection as exception:
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self.previous_line() # back up for another try
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next_state = exception.args[0]
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if len(exception.args) == 1:
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transitions = None
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else:
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transitions = (exception.args[1],)
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if self.debug:
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print((
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'\nStateMachine.run: StateCorrection to state '
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'"%s", transition %s.'
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% (next_state, transitions[0])), file=self._stderr)
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else:
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transitions = None
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state = self.get_state(next_state)
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except:
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if self.debug:
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self.error()
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raise
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self.observers = []
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return results
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def get_state(self, next_state=None):
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"""
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Return current state object; set it first if `next_state` given.
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Parameter `next_state`: a string, the name of the next state.
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Exception: `UnknownStateError` raised if `next_state` unknown.
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"""
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if next_state:
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if self.debug and next_state != self.current_state:
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print((
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'\nStateMachine.get_state: Changing state from '
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'"%s" to "%s" (input line %s).'
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% (self.current_state, next_state,
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self.abs_line_number())), file=self._stderr)
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self.current_state = next_state
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try:
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return self.states[self.current_state]
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except KeyError:
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raise UnknownStateError(self.current_state)
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def next_line(self, n=1):
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"""Load `self.line` with the `n`'th next line and return it."""
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try:
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try:
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self.line_offset += n
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self.line = self.input_lines[self.line_offset]
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except IndexError:
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self.line = None
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raise EOFError
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return self.line
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finally:
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self.notify_observers()
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def is_next_line_blank(self):
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"""Return 1 if the next line is blank or non-existant."""
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try:
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return not self.input_lines[self.line_offset + 1].strip()
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except IndexError:
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return 1
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def at_eof(self):
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"""Return 1 if the input is at or past end-of-file."""
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return self.line_offset >= len(self.input_lines) - 1
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def at_bof(self):
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"""Return 1 if the input is at or before beginning-of-file."""
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return self.line_offset <= 0
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def previous_line(self, n=1):
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"""Load `self.line` with the `n`'th previous line and return it."""
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self.line_offset -= n
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if self.line_offset < 0:
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self.line = None
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else:
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self.line = self.input_lines[self.line_offset]
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self.notify_observers()
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return self.line
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def goto_line(self, line_offset):
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"""Jump to absolute line offset `line_offset`, load and return it."""
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try:
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try:
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self.line_offset = line_offset - self.input_offset
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self.line = self.input_lines[self.line_offset]
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except IndexError:
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self.line = None
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raise EOFError
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return self.line
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finally:
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self.notify_observers()
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def get_source(self, line_offset):
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"""Return source of line at absolute line offset `line_offset`."""
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return self.input_lines.source(line_offset - self.input_offset)
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def abs_line_offset(self):
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"""Return line offset of current line, from beginning of file."""
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return self.line_offset + self.input_offset
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def abs_line_number(self):
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"""Return line number of current line (counting from 1)."""
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return self.line_offset + self.input_offset + 1
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def get_source_and_line(self, lineno=None):
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"""Return (source, line) tuple for current or given line number.
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Looks up the source and line number in the `self.input_lines`
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StringList instance to count for included source files.
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If the optional argument `lineno` is given, convert it from an
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absolute line number to the corresponding (source, line) pair.
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"""
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if lineno is None:
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offset = self.line_offset
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else:
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offset = lineno - self.input_offset - 1
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try:
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src, srcoffset = self.input_lines.info(offset)
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srcline = srcoffset + 1
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except (TypeError):
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# line is None if index is "Just past the end"
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src, srcline = self.get_source_and_line(offset + self.input_offset)
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return src, srcline + 1
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except (IndexError): # `offset` is off the list
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src, srcline = None, None
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# raise AssertionError('cannot find line %d in %s lines' %
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# (offset, len(self.input_lines)))
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# # list(self.input_lines.lines())))
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return (src, srcline)
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def insert_input(self, input_lines, source):
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self.input_lines.insert(self.line_offset + 1, '',
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source='internal padding after '+source,
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offset=len(input_lines))
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self.input_lines.insert(self.line_offset + 1, '',
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source='internal padding before '+source,
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offset=-1)
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self.input_lines.insert(self.line_offset + 2,
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StringList(input_lines, source))
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def get_text_block(self, flush_left=False):
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"""
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Return a contiguous block of text.
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If `flush_left` is true, raise `UnexpectedIndentationError` if an
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indented line is encountered before the text block ends (with a blank
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line).
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"""
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try:
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block = self.input_lines.get_text_block(self.line_offset,
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flush_left)
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self.next_line(len(block) - 1)
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return block
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except UnexpectedIndentationError as err:
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block = err.args[0]
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self.next_line(len(block) - 1) # advance to last line of block
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raise
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def check_line(self, context, state, transitions=None):
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"""
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Examine one line of input for a transition match & execute its method.
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Parameters:
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- `context`: application-dependent storage.
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- `state`: a `State` object, the current state.
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- `transitions`: an optional ordered list of transition names to try,
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instead of ``state.transition_order``.
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Return the values returned by the transition method:
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- context: possibly modified from the parameter `context`;
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- next state name (`State` subclass name);
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- the result output of the transition, a list.
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When there is no match, ``state.no_match()`` is called and its return
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value is returned.
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"""
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if transitions is None:
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transitions = state.transition_order
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state_correction = None
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if self.debug:
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print((
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'\nStateMachine.check_line: state="%s", transitions=%r.'
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% (state.__class__.__name__, transitions)), file=self._stderr)
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for name in transitions:
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pattern, method, next_state = state.transitions[name]
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match = pattern.match(self.line)
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if match:
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if self.debug:
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print((
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'\nStateMachine.check_line: Matched transition '
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'"%s" in state "%s".'
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% (name, state.__class__.__name__)), file=self._stderr)
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return method(match, context, next_state)
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else:
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if self.debug:
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print((
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'\nStateMachine.check_line: No match in state "%s".'
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% state.__class__.__name__), file=self._stderr)
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return state.no_match(context, transitions)
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def add_state(self, state_class):
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"""
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Initialize & add a `state_class` (`State` subclass) object.
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Exception: `DuplicateStateError` raised if `state_class` was already
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added.
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"""
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statename = state_class.__name__
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if statename in self.states:
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raise DuplicateStateError(statename)
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self.states[statename] = state_class(self, self.debug)
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def add_states(self, state_classes):
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"""
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Add `state_classes` (a list of `State` subclasses).
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"""
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for state_class in state_classes:
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self.add_state(state_class)
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|
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def runtime_init(self):
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"""
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Initialize `self.states`.
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"""
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for state in self.states.values():
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state.runtime_init()
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def error(self):
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"""Report error details."""
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type, value, module, line, function = _exception_data()
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print(u'%s: %s' % (type, value), file=self._stderr)
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print('input line %s' % (self.abs_line_number()), file=self._stderr)
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print((u'module %s, line %s, function %s' %
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(module, line, function)), file=self._stderr)
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def attach_observer(self, observer):
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"""
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|
The `observer` parameter is a function or bound method which takes two
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arguments, the source and offset of the current line.
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"""
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self.observers.append(observer)
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|
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def detach_observer(self, observer):
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self.observers.remove(observer)
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|
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def notify_observers(self):
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for observer in self.observers:
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try:
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info = self.input_lines.info(self.line_offset)
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except IndexError:
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info = (None, None)
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observer(*info)
|
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|
|
|
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class State(object):
|
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|
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"""
|
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State superclass. Contains a list of transitions, and transition methods.
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|
|
Transition methods all have the same signature. They take 3 parameters:
|
|
|
|
- An `re` match object. ``match.string`` contains the matched input line,
|
|
``match.start()`` gives the start index of the match, and
|
|
``match.end()`` gives the end index.
|
|
- A context object, whose meaning is application-defined (initial value
|
|
``None``). It can be used to store any information required by the state
|
|
machine, and the retured context is passed on to the next transition
|
|
method unchanged.
|
|
- The name of the next state, a string, taken from the transitions list;
|
|
normally it is returned unchanged, but it may be altered by the
|
|
transition method if necessary.
|
|
|
|
Transition methods all return a 3-tuple:
|
|
|
|
- A context object, as (potentially) modified by the transition method.
|
|
- The next state name (a return value of ``None`` means no state change).
|
|
- The processing result, a list, which is accumulated by the state
|
|
machine.
|
|
|
|
Transition methods may raise an `EOFError` to cut processing short.
|
|
|
|
There are two implicit transitions, and corresponding transition methods
|
|
are defined: `bof()` handles the beginning-of-file, and `eof()` handles
|
|
the end-of-file. These methods have non-standard signatures and return
|
|
values. `bof()` returns the initial context and results, and may be used
|
|
to return a header string, or do any other processing needed. `eof()`
|
|
should handle any remaining context and wrap things up; it returns the
|
|
final processing result.
|
|
|
|
Typical applications need only subclass `State` (or a subclass), set the
|
|
`patterns` and `initial_transitions` class attributes, and provide
|
|
corresponding transition methods. The default object initialization will
|
|
take care of constructing the list of transitions.
|
|
"""
|
|
|
|
patterns = None
|
|
"""
|
|
{Name: pattern} mapping, used by `make_transition()`. Each pattern may
|
|
be a string or a compiled `re` pattern. Override in subclasses.
|
|
"""
|
|
|
|
initial_transitions = None
|
|
"""
|
|
A list of transitions to initialize when a `State` is instantiated.
|
|
Each entry is either a transition name string, or a (transition name, next
|
|
state name) pair. See `make_transitions()`. Override in subclasses.
|
|
"""
|
|
|
|
nested_sm = None
|
|
"""
|
|
The `StateMachine` class for handling nested processing.
|
|
|
|
If left as ``None``, `nested_sm` defaults to the class of the state's
|
|
controlling state machine. Override it in subclasses to avoid the default.
|
|
"""
|
|
|
|
nested_sm_kwargs = None
|
|
"""
|
|
Keyword arguments dictionary, passed to the `nested_sm` constructor.
|
|
|
|
Two keys must have entries in the dictionary:
|
|
|
|
- Key 'state_classes' must be set to a list of `State` classes.
|
|
- Key 'initial_state' must be set to the name of the initial state class.
|
|
|
|
If `nested_sm_kwargs` is left as ``None``, 'state_classes' defaults to the
|
|
class of the current state, and 'initial_state' defaults to the name of
|
|
the class of the current state. Override in subclasses to avoid the
|
|
defaults.
|
|
"""
|
|
|
|
def __init__(self, state_machine, debug=False):
|
|
"""
|
|
Initialize a `State` object; make & add initial transitions.
|
|
|
|
Parameters:
|
|
|
|
- `statemachine`: the controlling `StateMachine` object.
|
|
- `debug`: a boolean; produce verbose output if true.
|
|
"""
|
|
|
|
self.transition_order = []
|
|
"""A list of transition names in search order."""
|
|
|
|
self.transitions = {}
|
|
"""
|
|
A mapping of transition names to 3-tuples containing
|
|
(compiled_pattern, transition_method, next_state_name). Initialized as
|
|
an instance attribute dynamically (instead of as a class attribute)
|
|
because it may make forward references to patterns and methods in this
|
|
or other classes.
|
|
"""
|
|
|
|
self.add_initial_transitions()
|
|
|
|
self.state_machine = state_machine
|
|
"""A reference to the controlling `StateMachine` object."""
|
|
|
|
self.debug = debug
|
|
"""Debugging mode on/off."""
|
|
|
|
if self.nested_sm is None:
|
|
self.nested_sm = self.state_machine.__class__
|
|
if self.nested_sm_kwargs is None:
|
|
self.nested_sm_kwargs = {'state_classes': [self.__class__],
|
|
'initial_state': self.__class__.__name__}
|
|
|
|
def runtime_init(self):
|
|
"""
|
|
Initialize this `State` before running the state machine; called from
|
|
`self.state_machine.run()`.
|
|
"""
|
|
pass
|
|
|
|
def unlink(self):
|
|
"""Remove circular references to objects no longer required."""
|
|
self.state_machine = None
|
|
|
|
def add_initial_transitions(self):
|
|
"""Make and add transitions listed in `self.initial_transitions`."""
|
|
if self.initial_transitions:
|
|
names, transitions = self.make_transitions(
|
|
self.initial_transitions)
|
|
self.add_transitions(names, transitions)
|
|
|
|
def add_transitions(self, names, transitions):
|
|
"""
|
|
Add a list of transitions to the start of the transition list.
|
|
|
|
Parameters:
|
|
|
|
- `names`: a list of transition names.
|
|
- `transitions`: a mapping of names to transition tuples.
|
|
|
|
Exceptions: `DuplicateTransitionError`, `UnknownTransitionError`.
|
|
"""
|
|
for name in names:
|
|
if name in self.transitions:
|
|
raise DuplicateTransitionError(name)
|
|
if name not in transitions:
|
|
raise UnknownTransitionError(name)
|
|
self.transition_order[:0] = names
|
|
self.transitions.update(transitions)
|
|
|
|
def add_transition(self, name, transition):
|
|
"""
|
|
Add a transition to the start of the transition list.
|
|
|
|
Parameter `transition`: a ready-made transition 3-tuple.
|
|
|
|
Exception: `DuplicateTransitionError`.
|
|
"""
|
|
if name in self.transitions:
|
|
raise DuplicateTransitionError(name)
|
|
self.transition_order[:0] = [name]
|
|
self.transitions[name] = transition
|
|
|
|
def remove_transition(self, name):
|
|
"""
|
|
Remove a transition by `name`.
|
|
|
|
Exception: `UnknownTransitionError`.
|
|
"""
|
|
try:
|
|
del self.transitions[name]
|
|
self.transition_order.remove(name)
|
|
except:
|
|
raise UnknownTransitionError(name)
|
|
|
|
def make_transition(self, name, next_state=None):
|
|
"""
|
|
Make & return a transition tuple based on `name`.
|
|
|
|
This is a convenience function to simplify transition creation.
|
|
|
|
Parameters:
|
|
|
|
- `name`: a string, the name of the transition pattern & method. This
|
|
`State` object must have a method called '`name`', and a dictionary
|
|
`self.patterns` containing a key '`name`'.
|
|
- `next_state`: a string, the name of the next `State` object for this
|
|
transition. A value of ``None`` (or absent) implies no state change
|
|
(i.e., continue with the same state).
|
|
|
|
Exceptions: `TransitionPatternNotFound`, `TransitionMethodNotFound`.
|
|
"""
|
|
if next_state is None:
|
|
next_state = self.__class__.__name__
|
|
try:
|
|
pattern = self.patterns[name]
|
|
if not hasattr(pattern, 'match'):
|
|
pattern = self.patterns[name] = re.compile(pattern)
|
|
except KeyError:
|
|
raise TransitionPatternNotFound(
|
|
'%s.patterns[%r]' % (self.__class__.__name__, name))
|
|
try:
|
|
method = getattr(self, name)
|
|
except AttributeError:
|
|
raise TransitionMethodNotFound(
|
|
'%s.%s' % (self.__class__.__name__, name))
|
|
return (pattern, method, next_state)
|
|
|
|
def make_transitions(self, name_list):
|
|
"""
|
|
Return a list of transition names and a transition mapping.
|
|
|
|
Parameter `name_list`: a list, where each entry is either a transition
|
|
name string, or a 1- or 2-tuple (transition name, optional next state
|
|
name).
|
|
"""
|
|
stringtype = type('')
|
|
names = []
|
|
transitions = {}
|
|
for namestate in name_list:
|
|
if isinstance(namestate, stringtype):
|
|
transitions[namestate] = self.make_transition(namestate)
|
|
names.append(namestate)
|
|
else:
|
|
transitions[namestate[0]] = self.make_transition(*namestate)
|
|
names.append(namestate[0])
|
|
return names, transitions
|
|
|
|
def no_match(self, context, transitions):
|
|
"""
|
|
Called when there is no match from `StateMachine.check_line()`.
|
|
|
|
Return the same values returned by transition methods:
|
|
|
|
- context: unchanged;
|
|
- next state name: ``None``;
|
|
- empty result list.
|
|
|
|
Override in subclasses to catch this event.
|
|
"""
|
|
return context, None, []
|
|
|
|
def bof(self, context):
|
|
"""
|
|
Handle beginning-of-file. Return unchanged `context`, empty result.
|
|
|
|
Override in subclasses.
|
|
|
|
Parameter `context`: application-defined storage.
|
|
"""
|
|
return context, []
|
|
|
|
def eof(self, context):
|
|
"""
|
|
Handle end-of-file. Return empty result.
|
|
|
|
Override in subclasses.
|
|
|
|
Parameter `context`: application-defined storage.
|
|
"""
|
|
return []
|
|
|
|
def nop(self, match, context, next_state):
|
|
"""
|
|
A "do nothing" transition method.
|
|
|
|
Return unchanged `context` & `next_state`, empty result. Useful for
|
|
simple state changes (actionless transitions).
|
|
"""
|
|
return context, next_state, []
|
|
|
|
|
|
class StateMachineWS(StateMachine):
|
|
|
|
"""
|
|
`StateMachine` subclass specialized for whitespace recognition.
|
|
|
|
There are three methods provided for extracting indented text blocks:
|
|
|
|
- `get_indented()`: use when the indent is unknown.
|
|
- `get_known_indented()`: use when the indent is known for all lines.
|
|
- `get_first_known_indented()`: use when only the first line's indent is
|
|
known.
|
|
"""
|
|
|
|
def get_indented(self, until_blank=False, strip_indent=True):
|
|
"""
|
|
Return a block of indented lines of text, and info.
|
|
|
|
Extract an indented block where the indent is unknown for all lines.
|
|
|
|
:Parameters:
|
|
- `until_blank`: Stop collecting at the first blank line if true.
|
|
- `strip_indent`: Strip common leading indent if true (default).
|
|
|
|
:Return:
|
|
- the indented block (a list of lines of text),
|
|
- its indent,
|
|
- its first line offset from BOF, and
|
|
- whether or not it finished with a blank line.
|
|
"""
|
|
offset = self.abs_line_offset()
|
|
indented, indent, blank_finish = self.input_lines.get_indented(
|
|
self.line_offset, until_blank, strip_indent)
|
|
if indented:
|
|
self.next_line(len(indented) - 1) # advance to last indented line
|
|
while indented and not indented[0].strip():
|
|
indented.trim_start()
|
|
offset += 1
|
|
return indented, indent, offset, blank_finish
|
|
|
|
def get_known_indented(self, indent, until_blank=False, strip_indent=True):
|
|
"""
|
|
Return an indented block and info.
|
|
|
|
Extract an indented block where the indent is known for all lines.
|
|
Starting with the current line, extract the entire text block with at
|
|
least `indent` indentation (which must be whitespace, except for the
|
|
first line).
|
|
|
|
:Parameters:
|
|
- `indent`: The number of indent columns/characters.
|
|
- `until_blank`: Stop collecting at the first blank line if true.
|
|
- `strip_indent`: Strip `indent` characters of indentation if true
|
|
(default).
|
|
|
|
:Return:
|
|
- the indented block,
|
|
- its first line offset from BOF, and
|
|
- whether or not it finished with a blank line.
|
|
"""
|
|
offset = self.abs_line_offset()
|
|
indented, indent, blank_finish = self.input_lines.get_indented(
|
|
self.line_offset, until_blank, strip_indent,
|
|
block_indent=indent)
|
|
self.next_line(len(indented) - 1) # advance to last indented line
|
|
while indented and not indented[0].strip():
|
|
indented.trim_start()
|
|
offset += 1
|
|
return indented, offset, blank_finish
|
|
|
|
def get_first_known_indented(self, indent, until_blank=False,
|
|
strip_indent=True, strip_top=True):
|
|
"""
|
|
Return an indented block and info.
|
|
|
|
Extract an indented block where the indent is known for the first line
|
|
and unknown for all other lines.
|
|
|
|
:Parameters:
|
|
- `indent`: The first line's indent (# of columns/characters).
|
|
- `until_blank`: Stop collecting at the first blank line if true
|
|
(1).
|
|
- `strip_indent`: Strip `indent` characters of indentation if true
|
|
(1, default).
|
|
- `strip_top`: Strip blank lines from the beginning of the block.
|
|
|
|
:Return:
|
|
- the indented block,
|
|
- its indent,
|
|
- its first line offset from BOF, and
|
|
- whether or not it finished with a blank line.
|
|
"""
|
|
offset = self.abs_line_offset()
|
|
indented, indent, blank_finish = self.input_lines.get_indented(
|
|
self.line_offset, until_blank, strip_indent,
|
|
first_indent=indent)
|
|
self.next_line(len(indented) - 1) # advance to last indented line
|
|
if strip_top:
|
|
while indented and not indented[0].strip():
|
|
indented.trim_start()
|
|
offset += 1
|
|
return indented, indent, offset, blank_finish
|
|
|
|
|
|
class StateWS(State):
|
|
|
|
"""
|
|
State superclass specialized for whitespace (blank lines & indents).
|
|
|
|
Use this class with `StateMachineWS`. The transitions 'blank' (for blank
|
|
lines) and 'indent' (for indented text blocks) are added automatically,
|
|
before any other transitions. The transition method `blank()` handles
|
|
blank lines and `indent()` handles nested indented blocks. Indented
|
|
blocks trigger a new state machine to be created by `indent()` and run.
|
|
The class of the state machine to be created is in `indent_sm`, and the
|
|
constructor keyword arguments are in the dictionary `indent_sm_kwargs`.
|
|
|
|
The methods `known_indent()` and `firstknown_indent()` are provided for
|
|
indented blocks where the indent (all lines' and first line's only,
|
|
respectively) is known to the transition method, along with the attributes
|
|
`known_indent_sm` and `known_indent_sm_kwargs`. Neither transition method
|
|
is triggered automatically.
|
|
"""
|
|
|
|
indent_sm = None
|
|
"""
|
|
The `StateMachine` class handling indented text blocks.
|
|
|
|
If left as ``None``, `indent_sm` defaults to the value of
|
|
`State.nested_sm`. Override it in subclasses to avoid the default.
|
|
"""
|
|
|
|
indent_sm_kwargs = None
|
|
"""
|
|
Keyword arguments dictionary, passed to the `indent_sm` constructor.
|
|
|
|
If left as ``None``, `indent_sm_kwargs` defaults to the value of
|
|
`State.nested_sm_kwargs`. Override it in subclasses to avoid the default.
|
|
"""
|
|
|
|
known_indent_sm = None
|
|
"""
|
|
The `StateMachine` class handling known-indented text blocks.
|
|
|
|
If left as ``None``, `known_indent_sm` defaults to the value of
|
|
`indent_sm`. Override it in subclasses to avoid the default.
|
|
"""
|
|
|
|
known_indent_sm_kwargs = None
|
|
"""
|
|
Keyword arguments dictionary, passed to the `known_indent_sm` constructor.
|
|
|
|
If left as ``None``, `known_indent_sm_kwargs` defaults to the value of
|
|
`indent_sm_kwargs`. Override it in subclasses to avoid the default.
|
|
"""
|
|
|
|
ws_patterns = {'blank': re.compile(' *$'),
|
|
'indent': re.compile(' +')}
|
|
"""Patterns for default whitespace transitions. May be overridden in
|
|
subclasses."""
|
|
|
|
ws_initial_transitions = ('blank', 'indent')
|
|
"""Default initial whitespace transitions, added before those listed in
|
|
`State.initial_transitions`. May be overridden in subclasses."""
|
|
|
|
def __init__(self, state_machine, debug=False):
|
|
"""
|
|
Initialize a `StateSM` object; extends `State.__init__()`.
|
|
|
|
Check for indent state machine attributes, set defaults if not set.
|
|
"""
|
|
State.__init__(self, state_machine, debug)
|
|
if self.indent_sm is None:
|
|
self.indent_sm = self.nested_sm
|
|
if self.indent_sm_kwargs is None:
|
|
self.indent_sm_kwargs = self.nested_sm_kwargs
|
|
if self.known_indent_sm is None:
|
|
self.known_indent_sm = self.indent_sm
|
|
if self.known_indent_sm_kwargs is None:
|
|
self.known_indent_sm_kwargs = self.indent_sm_kwargs
|
|
|
|
def add_initial_transitions(self):
|
|
"""
|
|
Add whitespace-specific transitions before those defined in subclass.
|
|
|
|
Extends `State.add_initial_transitions()`.
|
|
"""
|
|
State.add_initial_transitions(self)
|
|
if self.patterns is None:
|
|
self.patterns = {}
|
|
self.patterns.update(self.ws_patterns)
|
|
names, transitions = self.make_transitions(
|
|
self.ws_initial_transitions)
|
|
self.add_transitions(names, transitions)
|
|
|
|
def blank(self, match, context, next_state):
|
|
"""Handle blank lines. Does nothing. Override in subclasses."""
|
|
return self.nop(match, context, next_state)
|
|
|
|
def indent(self, match, context, next_state):
|
|
"""
|
|
Handle an indented text block. Extend or override in subclasses.
|
|
|
|
Recursively run the registered state machine for indented blocks
|
|
(`self.indent_sm`).
|
|
"""
|
|
indented, indent, line_offset, blank_finish = \
|
|
self.state_machine.get_indented()
|
|
sm = self.indent_sm(debug=self.debug, **self.indent_sm_kwargs)
|
|
results = sm.run(indented, input_offset=line_offset)
|
|
return context, next_state, results
|
|
|
|
def known_indent(self, match, context, next_state):
|
|
"""
|
|
Handle a known-indent text block. Extend or override in subclasses.
|
|
|
|
Recursively run the registered state machine for known-indent indented
|
|
blocks (`self.known_indent_sm`). The indent is the length of the
|
|
match, ``match.end()``.
|
|
"""
|
|
indented, line_offset, blank_finish = \
|
|
self.state_machine.get_known_indented(match.end())
|
|
sm = self.known_indent_sm(debug=self.debug,
|
|
**self.known_indent_sm_kwargs)
|
|
results = sm.run(indented, input_offset=line_offset)
|
|
return context, next_state, results
|
|
|
|
def first_known_indent(self, match, context, next_state):
|
|
"""
|
|
Handle an indented text block (first line's indent known).
|
|
|
|
Extend or override in subclasses.
|
|
|
|
Recursively run the registered state machine for known-indent indented
|
|
blocks (`self.known_indent_sm`). The indent is the length of the
|
|
match, ``match.end()``.
|
|
"""
|
|
indented, line_offset, blank_finish = \
|
|
self.state_machine.get_first_known_indented(match.end())
|
|
sm = self.known_indent_sm(debug=self.debug,
|
|
**self.known_indent_sm_kwargs)
|
|
results = sm.run(indented, input_offset=line_offset)
|
|
return context, next_state, results
|
|
|
|
|
|
class _SearchOverride(object):
|
|
|
|
"""
|
|
Mix-in class to override `StateMachine` regular expression behavior.
|
|
|
|
Changes regular expression matching, from the default `re.match()`
|
|
(succeeds only if the pattern matches at the start of `self.line`) to
|
|
`re.search()` (succeeds if the pattern matches anywhere in `self.line`).
|
|
When subclassing a `StateMachine`, list this class **first** in the
|
|
inheritance list of the class definition.
|
|
"""
|
|
|
|
def match(self, pattern):
|
|
"""
|
|
Return the result of a regular expression search.
|
|
|
|
Overrides `StateMachine.match()`.
|
|
|
|
Parameter `pattern`: `re` compiled regular expression.
|
|
"""
|
|
return pattern.search(self.line)
|
|
|
|
|
|
class SearchStateMachine(_SearchOverride, StateMachine):
|
|
"""`StateMachine` which uses `re.search()` instead of `re.match()`."""
|
|
pass
|
|
|
|
|
|
class SearchStateMachineWS(_SearchOverride, StateMachineWS):
|
|
"""`StateMachineWS` which uses `re.search()` instead of `re.match()`."""
|
|
pass
|
|
|
|
|
|
class ViewList(object):
|
|
|
|
"""
|
|
List with extended functionality: slices of ViewList objects are child
|
|
lists, linked to their parents. Changes made to a child list also affect
|
|
the parent list. A child list is effectively a "view" (in the SQL sense)
|
|
of the parent list. Changes to parent lists, however, do *not* affect
|
|
active child lists. If a parent list is changed, any active child lists
|
|
should be recreated.
|
|
|
|
The start and end of the slice can be trimmed using the `trim_start()` and
|
|
`trim_end()` methods, without affecting the parent list. The link between
|
|
child and parent lists can be broken by calling `disconnect()` on the
|
|
child list.
|
|
|
|
Also, ViewList objects keep track of the source & offset of each item.
|
|
This information is accessible via the `source()`, `offset()`, and
|
|
`info()` methods.
|
|
"""
|
|
|
|
def __init__(self, initlist=None, source=None, items=None,
|
|
parent=None, parent_offset=None):
|
|
self.data = []
|
|
"""The actual list of data, flattened from various sources."""
|
|
|
|
self.items = []
|
|
"""A list of (source, offset) pairs, same length as `self.data`: the
|
|
source of each line and the offset of each line from the beginning of
|
|
its source."""
|
|
|
|
self.parent = parent
|
|
"""The parent list."""
|
|
|
|
self.parent_offset = parent_offset
|
|
"""Offset of this list from the beginning of the parent list."""
|
|
|
|
if isinstance(initlist, ViewList):
|
|
self.data = initlist.data[:]
|
|
self.items = initlist.items[:]
|
|
elif initlist is not None:
|
|
self.data = list(initlist)
|
|
if items:
|
|
self.items = items
|
|
else:
|
|
self.items = [(source, i) for i in range(len(initlist))]
|
|
assert len(self.data) == len(self.items), 'data mismatch'
|
|
|
|
def __str__(self):
|
|
return str(self.data)
|
|
|
|
def __repr__(self):
|
|
return '%s(%s, items=%s)' % (self.__class__.__name__,
|
|
self.data, self.items)
|
|
|
|
def __lt__(self, other): return self.data < self.__cast(other)
|
|
def __le__(self, other): return self.data <= self.__cast(other)
|
|
def __eq__(self, other): return self.data == self.__cast(other)
|
|
def __ne__(self, other): return self.data != self.__cast(other)
|
|
def __gt__(self, other): return self.data > self.__cast(other)
|
|
def __ge__(self, other): return self.data >= self.__cast(other)
|
|
|
|
def __cmp__(self, other):
|
|
# from https://docs.python.org/3.0/whatsnew/3.0.html
|
|
mine = self.data
|
|
yours = self.__cast(other)
|
|
return (mine > yours) - (yours < mine)
|
|
|
|
def __cast(self, other):
|
|
if isinstance(other, ViewList):
|
|
return other.data
|
|
else:
|
|
return other
|
|
|
|
def __contains__(self, item): return item in self.data
|
|
def __len__(self): return len(self.data)
|
|
|
|
# The __getitem__()/__setitem__() methods check whether the index
|
|
# is a slice first, since indexing a native list with a slice object
|
|
# just works.
|
|
|
|
def __getitem__(self, i):
|
|
if isinstance(i, slice):
|
|
assert i.step in (None, 1), 'cannot handle slice with stride'
|
|
return self.__class__(self.data[i.start:i.stop],
|
|
items=self.items[i.start:i.stop],
|
|
parent=self, parent_offset=i.start or 0)
|
|
else:
|
|
return self.data[i]
|
|
|
|
def __setitem__(self, i, item):
|
|
if isinstance(i, slice):
|
|
assert i.step in (None, 1), 'cannot handle slice with stride'
|
|
if not isinstance(item, ViewList):
|
|
raise TypeError('assigning non-ViewList to ViewList slice')
|
|
self.data[i.start:i.stop] = item.data
|
|
self.items[i.start:i.stop] = item.items
|
|
assert len(self.data) == len(self.items), 'data mismatch'
|
|
if self.parent:
|
|
self.parent[(i.start or 0) + self.parent_offset
|
|
: (i.stop or len(self)) + self.parent_offset] = item
|
|
else:
|
|
self.data[i] = item
|
|
if self.parent:
|
|
self.parent[i + self.parent_offset] = item
|
|
|
|
def __delitem__(self, i):
|
|
try:
|
|
del self.data[i]
|
|
del self.items[i]
|
|
if self.parent:
|
|
del self.parent[i + self.parent_offset]
|
|
except TypeError:
|
|
assert i.step is None, 'cannot handle slice with stride'
|
|
del self.data[i.start:i.stop]
|
|
del self.items[i.start:i.stop]
|
|
if self.parent:
|
|
del self.parent[(i.start or 0) + self.parent_offset
|
|
: (i.stop or len(self)) + self.parent_offset]
|
|
|
|
def __add__(self, other):
|
|
if isinstance(other, ViewList):
|
|
return self.__class__(self.data + other.data,
|
|
items=(self.items + other.items))
|
|
else:
|
|
raise TypeError('adding non-ViewList to a ViewList')
|
|
|
|
def __radd__(self, other):
|
|
if isinstance(other, ViewList):
|
|
return self.__class__(other.data + self.data,
|
|
items=(other.items + self.items))
|
|
else:
|
|
raise TypeError('adding ViewList to a non-ViewList')
|
|
|
|
def __iadd__(self, other):
|
|
if isinstance(other, ViewList):
|
|
self.data += other.data
|
|
else:
|
|
raise TypeError('argument to += must be a ViewList')
|
|
return self
|
|
|
|
def __mul__(self, n):
|
|
return self.__class__(self.data * n, items=(self.items * n))
|
|
|
|
__rmul__ = __mul__
|
|
|
|
def __imul__(self, n):
|
|
self.data *= n
|
|
self.items *= n
|
|
return self
|
|
|
|
def extend(self, other):
|
|
if not isinstance(other, ViewList):
|
|
raise TypeError('extending a ViewList with a non-ViewList')
|
|
if self.parent:
|
|
self.parent.insert(len(self.data) + self.parent_offset, other)
|
|
self.data.extend(other.data)
|
|
self.items.extend(other.items)
|
|
|
|
def append(self, item, source=None, offset=0):
|
|
if source is None:
|
|
self.extend(item)
|
|
else:
|
|
if self.parent:
|
|
self.parent.insert(len(self.data) + self.parent_offset, item,
|
|
source, offset)
|
|
self.data.append(item)
|
|
self.items.append((source, offset))
|
|
|
|
def insert(self, i, item, source=None, offset=0):
|
|
if source is None:
|
|
if not isinstance(item, ViewList):
|
|
raise TypeError('inserting non-ViewList with no source given')
|
|
self.data[i:i] = item.data
|
|
self.items[i:i] = item.items
|
|
if self.parent:
|
|
index = (len(self.data) + i) % len(self.data)
|
|
self.parent.insert(index + self.parent_offset, item)
|
|
else:
|
|
self.data.insert(i, item)
|
|
self.items.insert(i, (source, offset))
|
|
if self.parent:
|
|
index = (len(self.data) + i) % len(self.data)
|
|
self.parent.insert(index + self.parent_offset, item,
|
|
source, offset)
|
|
|
|
def pop(self, i=-1):
|
|
if self.parent:
|
|
index = (len(self.data) + i) % len(self.data)
|
|
self.parent.pop(index + self.parent_offset)
|
|
self.items.pop(i)
|
|
return self.data.pop(i)
|
|
|
|
def trim_start(self, n=1):
|
|
"""
|
|
Remove items from the start of the list, without touching the parent.
|
|
"""
|
|
if n > len(self.data):
|
|
raise IndexError("Size of trim too large; can't trim %s items "
|
|
"from a list of size %s." % (n, len(self.data)))
|
|
elif n < 0:
|
|
raise IndexError('Trim size must be >= 0.')
|
|
del self.data[:n]
|
|
del self.items[:n]
|
|
if self.parent:
|
|
self.parent_offset += n
|
|
|
|
def trim_end(self, n=1):
|
|
"""
|
|
Remove items from the end of the list, without touching the parent.
|
|
"""
|
|
if n > len(self.data):
|
|
raise IndexError("Size of trim too large; can't trim %s items "
|
|
"from a list of size %s." % (n, len(self.data)))
|
|
elif n < 0:
|
|
raise IndexError('Trim size must be >= 0.')
|
|
del self.data[-n:]
|
|
del self.items[-n:]
|
|
|
|
def remove(self, item):
|
|
index = self.index(item)
|
|
del self[index]
|
|
|
|
def count(self, item): return self.data.count(item)
|
|
def index(self, item): return self.data.index(item)
|
|
|
|
def reverse(self):
|
|
self.data.reverse()
|
|
self.items.reverse()
|
|
self.parent = None
|
|
|
|
def sort(self, *args):
|
|
tmp = sorted(zip(self.data, self.items), *args)
|
|
self.data = [entry[0] for entry in tmp]
|
|
self.items = [entry[1] for entry in tmp]
|
|
self.parent = None
|
|
|
|
def info(self, i):
|
|
"""Return source & offset for index `i`."""
|
|
try:
|
|
return self.items[i]
|
|
except IndexError:
|
|
if i == len(self.data): # Just past the end
|
|
return self.items[i - 1][0], None
|
|
else:
|
|
raise
|
|
|
|
def source(self, i):
|
|
"""Return source for index `i`."""
|
|
return self.info(i)[0]
|
|
|
|
def offset(self, i):
|
|
"""Return offset for index `i`."""
|
|
return self.info(i)[1]
|
|
|
|
def disconnect(self):
|
|
"""Break link between this list and parent list."""
|
|
self.parent = None
|
|
|
|
def xitems(self):
|
|
"""Return iterator yielding (source, offset, value) tuples."""
|
|
for (value, (source, offset)) in zip(self.data, self.items):
|
|
yield (source, offset, value)
|
|
|
|
def pprint(self):
|
|
"""Print the list in `grep` format (`source:offset:value` lines)"""
|
|
for line in self.xitems():
|
|
print("%s:%d:%s" % line)
|
|
|
|
|
|
class StringList(ViewList):
|
|
|
|
"""A `ViewList` with string-specific methods."""
|
|
|
|
def trim_left(self, length, start=0, end=sys.maxsize):
|
|
"""
|
|
Trim `length` characters off the beginning of each item, in-place,
|
|
from index `start` to `end`. No whitespace-checking is done on the
|
|
trimmed text. Does not affect slice parent.
|
|
"""
|
|
self.data[start:end] = [line[length:]
|
|
for line in self.data[start:end]]
|
|
|
|
def get_text_block(self, start, flush_left=False):
|
|
"""
|
|
Return a contiguous block of text.
|
|
|
|
If `flush_left` is true, raise `UnexpectedIndentationError` if an
|
|
indented line is encountered before the text block ends (with a blank
|
|
line).
|
|
"""
|
|
end = start
|
|
last = len(self.data)
|
|
while end < last:
|
|
line = self.data[end]
|
|
if not line.strip():
|
|
break
|
|
if flush_left and (line[0] == ' '):
|
|
source, offset = self.info(end)
|
|
raise UnexpectedIndentationError(self[start:end], source,
|
|
offset + 1)
|
|
end += 1
|
|
return self[start:end]
|
|
|
|
def get_indented(self, start=0, until_blank=False, strip_indent=True,
|
|
block_indent=None, first_indent=None):
|
|
"""
|
|
Extract and return a StringList of indented lines of text.
|
|
|
|
Collect all lines with indentation, determine the minimum indentation,
|
|
remove the minimum indentation from all indented lines (unless
|
|
`strip_indent` is false), and return them. All lines up to but not
|
|
including the first unindented line will be returned.
|
|
|
|
:Parameters:
|
|
- `start`: The index of the first line to examine.
|
|
- `until_blank`: Stop collecting at the first blank line if true.
|
|
- `strip_indent`: Strip common leading indent if true (default).
|
|
- `block_indent`: The indent of the entire block, if known.
|
|
- `first_indent`: The indent of the first line, if known.
|
|
|
|
:Return:
|
|
- a StringList of indented lines with mininum indent removed;
|
|
- the amount of the indent;
|
|
- a boolean: did the indented block finish with a blank line or EOF?
|
|
"""
|
|
indent = block_indent # start with None if unknown
|
|
end = start
|
|
if block_indent is not None and first_indent is None:
|
|
first_indent = block_indent
|
|
if first_indent is not None:
|
|
end += 1
|
|
last = len(self.data)
|
|
while end < last:
|
|
line = self.data[end]
|
|
if line and (line[0] != ' '
|
|
or (block_indent is not None
|
|
and line[:block_indent].strip())):
|
|
# Line not indented or insufficiently indented.
|
|
# Block finished properly iff the last indented line blank:
|
|
blank_finish = ((end > start)
|
|
and not self.data[end - 1].strip())
|
|
break
|
|
stripped = line.lstrip()
|
|
if not stripped: # blank line
|
|
if until_blank:
|
|
blank_finish = 1
|
|
break
|
|
elif block_indent is None:
|
|
line_indent = len(line) - len(stripped)
|
|
if indent is None:
|
|
indent = line_indent
|
|
else:
|
|
indent = min(indent, line_indent)
|
|
end += 1
|
|
else:
|
|
blank_finish = 1 # block ends at end of lines
|
|
block = self[start:end]
|
|
if first_indent is not None and block:
|
|
block.data[0] = block.data[0][first_indent:]
|
|
if indent and strip_indent:
|
|
block.trim_left(indent, start=(first_indent is not None))
|
|
return block, indent or 0, blank_finish
|
|
|
|
def get_2D_block(self, top, left, bottom, right, strip_indent=True):
|
|
block = self[top:bottom]
|
|
indent = right
|
|
for i in range(len(block.data)):
|
|
# get slice from line, care for combining characters
|
|
ci = utils.column_indices(block.data[i])
|
|
try:
|
|
left = ci[left]
|
|
except IndexError:
|
|
left += len(block.data[i]) - len(ci)
|
|
try:
|
|
right = ci[right]
|
|
except IndexError:
|
|
right += len(block.data[i]) - len(ci)
|
|
block.data[i] = line = block.data[i][left:right].rstrip()
|
|
if line:
|
|
indent = min(indent, len(line) - len(line.lstrip()))
|
|
if strip_indent and 0 < indent < right:
|
|
block.data = [line[indent:] for line in block.data]
|
|
return block
|
|
|
|
def pad_double_width(self, pad_char):
|
|
"""
|
|
Pad all double-width characters in self by appending `pad_char` to each.
|
|
For East Asian language support.
|
|
"""
|
|
east_asian_width = unicodedata.east_asian_width
|
|
for i in range(len(self.data)):
|
|
line = self.data[i]
|
|
if isinstance(line, unicode):
|
|
new = []
|
|
for char in line:
|
|
new.append(char)
|
|
if east_asian_width(char) in 'WF': # 'W'ide & 'F'ull-width
|
|
new.append(pad_char)
|
|
self.data[i] = ''.join(new)
|
|
|
|
def replace(self, old, new):
|
|
"""Replace all occurrences of substring `old` with `new`."""
|
|
for i in range(len(self.data)):
|
|
self.data[i] = self.data[i].replace(old, new)
|
|
|
|
|
|
class StateMachineError(Exception): pass
|
|
class UnknownStateError(StateMachineError): pass
|
|
class DuplicateStateError(StateMachineError): pass
|
|
class UnknownTransitionError(StateMachineError): pass
|
|
class DuplicateTransitionError(StateMachineError): pass
|
|
class TransitionPatternNotFound(StateMachineError): pass
|
|
class TransitionMethodNotFound(StateMachineError): pass
|
|
class UnexpectedIndentationError(StateMachineError): pass
|
|
|
|
|
|
class TransitionCorrection(Exception):
|
|
|
|
"""
|
|
Raise from within a transition method to switch to another transition.
|
|
|
|
Raise with one argument, the new transition name.
|
|
"""
|
|
|
|
|
|
class StateCorrection(Exception):
|
|
|
|
"""
|
|
Raise from within a transition method to switch to another state.
|
|
|
|
Raise with one or two arguments: new state name, and an optional new
|
|
transition name.
|
|
"""
|
|
|
|
def string2lines(astring, tab_width=8, convert_whitespace=False,
|
|
whitespace=re.compile('[\v\f]')):
|
|
"""
|
|
Return a list of one-line strings with tabs expanded, no newlines, and
|
|
trailing whitespace stripped.
|
|
|
|
Each tab is expanded with between 1 and `tab_width` spaces, so that the
|
|
next character's index becomes a multiple of `tab_width` (8 by default).
|
|
|
|
Parameters:
|
|
|
|
- `astring`: a multi-line string.
|
|
- `tab_width`: the number of columns between tab stops.
|
|
- `convert_whitespace`: convert form feeds and vertical tabs to spaces?
|
|
"""
|
|
if convert_whitespace:
|
|
astring = whitespace.sub(' ', astring)
|
|
# TODO: add a test for too long lines (max_line_lenght = 1000, say)?
|
|
# See bug #381.
|
|
return [s.expandtabs(tab_width).rstrip() for s in astring.splitlines()]
|
|
|
|
def _exception_data():
|
|
"""
|
|
Return exception information:
|
|
|
|
- the exception's class name;
|
|
- the exception object;
|
|
- the name of the file containing the offending code;
|
|
- the line number of the offending code;
|
|
- the function name of the offending code.
|
|
"""
|
|
type, value, traceback = sys.exc_info()
|
|
while traceback.tb_next:
|
|
traceback = traceback.tb_next
|
|
code = traceback.tb_frame.f_code
|
|
return (type.__name__, value, code.co_filename, traceback.tb_lineno,
|
|
code.co_name)
|
|
|