[3] | 1 | # Author: David Goodger |
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| 2 | # Contact: goodger@users.sourceforge.net |
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| 3 | # Revision: $Revision: 4152 $ |
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| 4 | # Date: $Date: 2005-12-08 00:46:30 +0100 (Thu, 08 Dec 2005) $ |
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| 5 | # Copyright: This module has been placed in the public domain. |
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| 6 | |
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| 7 | """ |
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| 8 | A finite state machine specialized for regular-expression-based text filters, |
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| 9 | this module defines the following classes: |
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| 10 | |
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| 11 | - `StateMachine`, a state machine |
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| 12 | - `State`, a state superclass |
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| 13 | - `StateMachineWS`, a whitespace-sensitive version of `StateMachine` |
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| 14 | - `StateWS`, a state superclass for use with `StateMachineWS` |
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| 15 | - `SearchStateMachine`, uses `re.search()` instead of `re.match()` |
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| 16 | - `SearchStateMachineWS`, uses `re.search()` instead of `re.match()` |
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| 17 | - `ViewList`, extends standard Python lists. |
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| 18 | - `StringList`, string-specific ViewList. |
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| 19 | |
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| 20 | Exception classes: |
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| 21 | |
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| 22 | - `StateMachineError` |
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| 23 | - `UnknownStateError` |
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| 24 | - `DuplicateStateError` |
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| 25 | - `UnknownTransitionError` |
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| 26 | - `DuplicateTransitionError` |
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| 27 | - `TransitionPatternNotFound` |
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| 28 | - `TransitionMethodNotFound` |
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| 29 | - `UnexpectedIndentationError` |
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| 30 | - `TransitionCorrection`: Raised to switch to another transition. |
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| 31 | - `StateCorrection`: Raised to switch to another state & transition. |
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| 32 | |
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| 33 | Functions: |
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| 34 | |
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| 35 | - `string2lines()`: split a multi-line string into a list of one-line strings |
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| 36 | |
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| 37 | |
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| 38 | How To Use This Module |
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| 39 | ====================== |
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| 40 | (See the individual classes, methods, and attributes for details.) |
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| 41 | |
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| 42 | 1. Import it: ``import statemachine`` or ``from statemachine import ...``. |
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| 43 | You will also need to ``import re``. |
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| 44 | |
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| 45 | 2. Derive a subclass of `State` (or `StateWS`) for each state in your state |
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| 46 | machine:: |
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| 47 | |
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| 48 | class MyState(statemachine.State): |
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| 49 | |
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| 50 | Within the state's class definition: |
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| 51 | |
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| 52 | a) Include a pattern for each transition, in `State.patterns`:: |
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| 53 | |
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| 54 | patterns = {'atransition': r'pattern', ...} |
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| 55 | |
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| 56 | b) Include a list of initial transitions to be set up automatically, in |
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| 57 | `State.initial_transitions`:: |
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| 58 | |
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| 59 | initial_transitions = ['atransition', ...] |
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| 60 | |
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| 61 | c) Define a method for each transition, with the same name as the |
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| 62 | transition pattern:: |
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| 63 | |
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| 64 | def atransition(self, match, context, next_state): |
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| 65 | # do something |
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| 66 | result = [...] # a list |
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| 67 | return context, next_state, result |
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| 68 | # context, next_state may be altered |
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| 69 | |
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| 70 | Transition methods may raise an `EOFError` to cut processing short. |
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| 71 | |
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| 72 | d) You may wish to override the `State.bof()` and/or `State.eof()` implicit |
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| 73 | transition methods, which handle the beginning- and end-of-file. |
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| 74 | |
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| 75 | e) In order to handle nested processing, you may wish to override the |
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| 76 | attributes `State.nested_sm` and/or `State.nested_sm_kwargs`. |
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| 77 | |
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| 78 | If you are using `StateWS` as a base class, in order to handle nested |
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| 79 | indented blocks, you may wish to: |
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| 80 | |
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| 81 | - override the attributes `StateWS.indent_sm`, |
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| 82 | `StateWS.indent_sm_kwargs`, `StateWS.known_indent_sm`, and/or |
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| 83 | `StateWS.known_indent_sm_kwargs`; |
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| 84 | - override the `StateWS.blank()` method; and/or |
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| 85 | - override or extend the `StateWS.indent()`, `StateWS.known_indent()`, |
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| 86 | and/or `StateWS.firstknown_indent()` methods. |
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| 87 | |
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| 88 | 3. Create a state machine object:: |
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| 89 | |
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| 90 | sm = StateMachine(state_classes=[MyState, ...], |
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| 91 | initial_state='MyState') |
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| 92 | |
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| 93 | 4. Obtain the input text, which needs to be converted into a tab-free list of |
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| 94 | one-line strings. For example, to read text from a file called |
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| 95 | 'inputfile':: |
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| 96 | |
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| 97 | input_string = open('inputfile').read() |
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| 98 | input_lines = statemachine.string2lines(input_string) |
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| 99 | |
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| 100 | 5. Run the state machine on the input text and collect the results, a list:: |
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| 101 | |
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| 102 | results = sm.run(input_lines) |
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| 103 | |
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| 104 | 6. Remove any lingering circular references:: |
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| 105 | |
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| 106 | sm.unlink() |
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| 107 | """ |
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| 108 | |
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| 109 | __docformat__ = 'restructuredtext' |
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| 110 | |
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| 111 | import sys |
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| 112 | import re |
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| 113 | import types |
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| 114 | import unicodedata |
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| 115 | |
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| 116 | |
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| 117 | class StateMachine: |
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| 118 | |
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| 119 | """ |
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| 120 | A finite state machine for text filters using regular expressions. |
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| 121 | |
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| 122 | The input is provided in the form of a list of one-line strings (no |
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| 123 | newlines). States are subclasses of the `State` class. Transitions consist |
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| 124 | of regular expression patterns and transition methods, and are defined in |
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| 125 | each state. |
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| 126 | |
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| 127 | The state machine is started with the `run()` method, which returns the |
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| 128 | results of processing in a list. |
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| 129 | """ |
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| 130 | |
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| 131 | def __init__(self, state_classes, initial_state, debug=0): |
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| 132 | """ |
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| 133 | Initialize a `StateMachine` object; add state objects. |
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| 134 | |
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| 135 | Parameters: |
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| 136 | |
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| 137 | - `state_classes`: a list of `State` (sub)classes. |
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| 138 | - `initial_state`: a string, the class name of the initial state. |
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| 139 | - `debug`: a boolean; produce verbose output if true (nonzero). |
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| 140 | """ |
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| 141 | |
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| 142 | self.input_lines = None |
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| 143 | """`StringList` of input lines (without newlines). |
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| 144 | Filled by `self.run()`.""" |
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| 145 | |
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| 146 | self.input_offset = 0 |
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| 147 | """Offset of `self.input_lines` from the beginning of the file.""" |
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| 148 | |
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| 149 | self.line = None |
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| 150 | """Current input line.""" |
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| 151 | |
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| 152 | self.line_offset = -1 |
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| 153 | """Current input line offset from beginning of `self.input_lines`.""" |
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| 154 | |
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| 155 | self.debug = debug |
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| 156 | """Debugging mode on/off.""" |
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| 157 | |
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| 158 | self.initial_state = initial_state |
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| 159 | """The name of the initial state (key to `self.states`).""" |
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| 160 | |
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| 161 | self.current_state = initial_state |
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| 162 | """The name of the current state (key to `self.states`).""" |
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| 163 | |
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| 164 | self.states = {} |
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| 165 | """Mapping of {state_name: State_object}.""" |
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| 166 | |
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| 167 | self.add_states(state_classes) |
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| 168 | |
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| 169 | self.observers = [] |
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| 170 | """List of bound methods or functions to call whenever the current |
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| 171 | line changes. Observers are called with one argument, ``self``. |
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| 172 | Cleared at the end of `run()`.""" |
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| 173 | |
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| 174 | def unlink(self): |
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| 175 | """Remove circular references to objects no longer required.""" |
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| 176 | for state in self.states.values(): |
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| 177 | state.unlink() |
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| 178 | self.states = None |
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| 179 | |
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| 180 | def run(self, input_lines, input_offset=0, context=None, |
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| 181 | input_source=None): |
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| 182 | """ |
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| 183 | Run the state machine on `input_lines`. Return results (a list). |
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| 184 | |
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| 185 | Reset `self.line_offset` and `self.current_state`. Run the |
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| 186 | beginning-of-file transition. Input one line at a time and check for a |
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| 187 | matching transition. If a match is found, call the transition method |
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| 188 | and possibly change the state. Store the context returned by the |
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| 189 | transition method to be passed on to the next transition matched. |
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| 190 | Accumulate the results returned by the transition methods in a list. |
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| 191 | Run the end-of-file transition. Finally, return the accumulated |
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| 192 | results. |
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| 193 | |
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| 194 | Parameters: |
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| 195 | |
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| 196 | - `input_lines`: a list of strings without newlines, or `StringList`. |
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| 197 | - `input_offset`: the line offset of `input_lines` from the beginning |
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| 198 | of the file. |
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| 199 | - `context`: application-specific storage. |
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| 200 | - `input_source`: name or path of source of `input_lines`. |
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| 201 | """ |
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| 202 | self.runtime_init() |
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| 203 | if isinstance(input_lines, StringList): |
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| 204 | self.input_lines = input_lines |
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| 205 | else: |
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| 206 | self.input_lines = StringList(input_lines, source=input_source) |
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| 207 | self.input_offset = input_offset |
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| 208 | self.line_offset = -1 |
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| 209 | self.current_state = self.initial_state |
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| 210 | if self.debug: |
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| 211 | print >>sys.stderr, ( |
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| 212 | '\nStateMachine.run: input_lines (line_offset=%s):\n| %s' |
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| 213 | % (self.line_offset, '\n| '.join(self.input_lines))) |
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| 214 | transitions = None |
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| 215 | results = [] |
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| 216 | state = self.get_state() |
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| 217 | try: |
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| 218 | if self.debug: |
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| 219 | print >>sys.stderr, ('\nStateMachine.run: bof transition') |
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| 220 | context, result = state.bof(context) |
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| 221 | results.extend(result) |
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| 222 | while 1: |
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| 223 | try: |
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| 224 | try: |
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| 225 | self.next_line() |
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| 226 | if self.debug: |
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| 227 | source, offset = self.input_lines.info( |
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| 228 | self.line_offset) |
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| 229 | print >>sys.stderr, ( |
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| 230 | '\nStateMachine.run: line (source=%r, ' |
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| 231 | 'offset=%r):\n| %s' |
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| 232 | % (source, offset, self.line)) |
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| 233 | context, next_state, result = self.check_line( |
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| 234 | context, state, transitions) |
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| 235 | except EOFError: |
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| 236 | if self.debug: |
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| 237 | print >>sys.stderr, ( |
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| 238 | '\nStateMachine.run: %s.eof transition' |
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| 239 | % state.__class__.__name__) |
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| 240 | result = state.eof(context) |
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| 241 | results.extend(result) |
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| 242 | break |
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| 243 | else: |
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| 244 | results.extend(result) |
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| 245 | except TransitionCorrection, exception: |
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| 246 | self.previous_line() # back up for another try |
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| 247 | transitions = (exception.args[0],) |
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| 248 | if self.debug: |
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| 249 | print >>sys.stderr, ( |
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| 250 | '\nStateMachine.run: TransitionCorrection to ' |
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| 251 | 'state "%s", transition %s.' |
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| 252 | % (state.__class__.__name__, transitions[0])) |
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| 253 | continue |
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| 254 | except StateCorrection, exception: |
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| 255 | self.previous_line() # back up for another try |
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| 256 | next_state = exception.args[0] |
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| 257 | if len(exception.args) == 1: |
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| 258 | transitions = None |
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| 259 | else: |
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| 260 | transitions = (exception.args[1],) |
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| 261 | if self.debug: |
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| 262 | print >>sys.stderr, ( |
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| 263 | '\nStateMachine.run: StateCorrection to state ' |
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| 264 | '"%s", transition %s.' |
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| 265 | % (next_state, transitions[0])) |
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| 266 | else: |
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| 267 | transitions = None |
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| 268 | state = self.get_state(next_state) |
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| 269 | except: |
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| 270 | if self.debug: |
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| 271 | self.error() |
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| 272 | raise |
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| 273 | self.observers = [] |
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| 274 | return results |
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| 275 | |
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| 276 | def get_state(self, next_state=None): |
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| 277 | """ |
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| 278 | Return current state object; set it first if `next_state` given. |
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| 279 | |
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| 280 | Parameter `next_state`: a string, the name of the next state. |
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| 281 | |
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| 282 | Exception: `UnknownStateError` raised if `next_state` unknown. |
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| 283 | """ |
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| 284 | if next_state: |
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| 285 | if self.debug and next_state != self.current_state: |
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| 286 | print >>sys.stderr, \ |
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| 287 | ('\nStateMachine.get_state: Changing state from ' |
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| 288 | '"%s" to "%s" (input line %s).' |
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| 289 | % (self.current_state, next_state, |
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| 290 | self.abs_line_number())) |
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| 291 | self.current_state = next_state |
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| 292 | try: |
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| 293 | return self.states[self.current_state] |
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| 294 | except KeyError: |
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| 295 | raise UnknownStateError(self.current_state) |
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| 296 | |
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| 297 | def next_line(self, n=1): |
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| 298 | """Load `self.line` with the `n`'th next line and return it.""" |
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| 299 | try: |
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| 300 | try: |
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| 301 | self.line_offset += n |
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| 302 | self.line = self.input_lines[self.line_offset] |
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| 303 | except IndexError: |
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| 304 | self.line = None |
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| 305 | raise EOFError |
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| 306 | return self.line |
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| 307 | finally: |
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| 308 | self.notify_observers() |
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| 309 | |
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| 310 | def is_next_line_blank(self): |
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| 311 | """Return 1 if the next line is blank or non-existant.""" |
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| 312 | try: |
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| 313 | return not self.input_lines[self.line_offset + 1].strip() |
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| 314 | except IndexError: |
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| 315 | return 1 |
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| 316 | |
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| 317 | def at_eof(self): |
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| 318 | """Return 1 if the input is at or past end-of-file.""" |
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| 319 | return self.line_offset >= len(self.input_lines) - 1 |
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| 320 | |
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| 321 | def at_bof(self): |
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| 322 | """Return 1 if the input is at or before beginning-of-file.""" |
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| 323 | return self.line_offset <= 0 |
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| 324 | |
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| 325 | def previous_line(self, n=1): |
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| 326 | """Load `self.line` with the `n`'th previous line and return it.""" |
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| 327 | self.line_offset -= n |
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| 328 | if self.line_offset < 0: |
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| 329 | self.line = None |
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| 330 | else: |
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| 331 | self.line = self.input_lines[self.line_offset] |
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| 332 | self.notify_observers() |
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| 333 | return self.line |
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| 334 | |
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| 335 | def goto_line(self, line_offset): |
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| 336 | """Jump to absolute line offset `line_offset`, load and return it.""" |
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| 337 | try: |
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| 338 | try: |
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| 339 | self.line_offset = line_offset - self.input_offset |
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| 340 | self.line = self.input_lines[self.line_offset] |
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| 341 | except IndexError: |
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| 342 | self.line = None |
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| 343 | raise EOFError |
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| 344 | return self.line |
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| 345 | finally: |
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| 346 | self.notify_observers() |
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| 347 | |
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| 348 | def get_source(self, line_offset): |
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| 349 | """Return source of line at absolute line offset `line_offset`.""" |
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| 350 | return self.input_lines.source(line_offset - self.input_offset) |
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| 351 | |
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| 352 | def abs_line_offset(self): |
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| 353 | """Return line offset of current line, from beginning of file.""" |
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| 354 | return self.line_offset + self.input_offset |
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| 355 | |
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| 356 | def abs_line_number(self): |
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| 357 | """Return line number of current line (counting from 1).""" |
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| 358 | return self.line_offset + self.input_offset + 1 |
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| 359 | |
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| 360 | def insert_input(self, input_lines, source): |
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| 361 | self.input_lines.insert(self.line_offset + 1, '', |
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| 362 | source='internal padding') |
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| 363 | self.input_lines.insert(self.line_offset + 1, '', |
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| 364 | source='internal padding') |
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| 365 | self.input_lines.insert(self.line_offset + 2, |
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| 366 | StringList(input_lines, source)) |
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| 367 | |
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| 368 | def get_text_block(self, flush_left=0): |
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| 369 | """ |
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| 370 | Return a contiguous block of text. |
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| 371 | |
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| 372 | If `flush_left` is true, raise `UnexpectedIndentationError` if an |
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| 373 | indented line is encountered before the text block ends (with a blank |
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| 374 | line). |
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| 375 | """ |
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| 376 | try: |
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| 377 | block = self.input_lines.get_text_block(self.line_offset, |
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| 378 | flush_left) |
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| 379 | self.next_line(len(block) - 1) |
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| 380 | return block |
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| 381 | except UnexpectedIndentationError, error: |
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| 382 | block, source, lineno = error |
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| 383 | self.next_line(len(block) - 1) # advance to last line of block |
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| 384 | raise |
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| 385 | |
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| 386 | def check_line(self, context, state, transitions=None): |
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| 387 | """ |
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| 388 | Examine one line of input for a transition match & execute its method. |
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| 389 | |
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| 390 | Parameters: |
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| 391 | |
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| 392 | - `context`: application-dependent storage. |
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| 393 | - `state`: a `State` object, the current state. |
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| 394 | - `transitions`: an optional ordered list of transition names to try, |
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| 395 | instead of ``state.transition_order``. |
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| 396 | |
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| 397 | Return the values returned by the transition method: |
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| 398 | |
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| 399 | - context: possibly modified from the parameter `context`; |
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| 400 | - next state name (`State` subclass name); |
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| 401 | - the result output of the transition, a list. |
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| 402 | |
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| 403 | When there is no match, ``state.no_match()`` is called and its return |
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| 404 | value is returned. |
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| 405 | """ |
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| 406 | if transitions is None: |
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| 407 | transitions = state.transition_order |
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| 408 | state_correction = None |
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| 409 | if self.debug: |
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| 410 | print >>sys.stderr, ( |
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| 411 | '\nStateMachine.check_line: state="%s", transitions=%r.' |
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| 412 | % (state.__class__.__name__, transitions)) |
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| 413 | for name in transitions: |
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| 414 | pattern, method, next_state = state.transitions[name] |
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| 415 | match = self.match(pattern) |
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| 416 | if match: |
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| 417 | if self.debug: |
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| 418 | print >>sys.stderr, ( |
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| 419 | '\nStateMachine.check_line: Matched transition ' |
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| 420 | '"%s" in state "%s".' |
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| 421 | % (name, state.__class__.__name__)) |
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| 422 | return method(match, context, next_state) |
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| 423 | else: |
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| 424 | if self.debug: |
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| 425 | print >>sys.stderr, ( |
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| 426 | '\nStateMachine.check_line: No match in state "%s".' |
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| 427 | % state.__class__.__name__) |
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| 428 | return state.no_match(context, transitions) |
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| 429 | |
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| 430 | def match(self, pattern): |
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| 431 | """ |
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| 432 | Return the result of a regular expression match. |
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| 433 | |
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| 434 | Parameter `pattern`: an `re` compiled regular expression. |
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| 435 | """ |
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| 436 | return pattern.match(self.line) |
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| 437 | |
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| 438 | def add_state(self, state_class): |
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| 439 | """ |
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| 440 | Initialize & add a `state_class` (`State` subclass) object. |
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| 441 | |
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| 442 | Exception: `DuplicateStateError` raised if `state_class` was already |
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| 443 | added. |
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| 444 | """ |
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| 445 | statename = state_class.__name__ |
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| 446 | if self.states.has_key(statename): |
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| 447 | raise DuplicateStateError(statename) |
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| 448 | self.states[statename] = state_class(self, self.debug) |
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| 449 | |
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| 450 | def add_states(self, state_classes): |
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| 451 | """ |
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| 452 | Add `state_classes` (a list of `State` subclasses). |
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| 453 | """ |
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| 454 | for state_class in state_classes: |
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| 455 | self.add_state(state_class) |
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| 456 | |
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| 457 | def runtime_init(self): |
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| 458 | """ |
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| 459 | Initialize `self.states`. |
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| 460 | """ |
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| 461 | for state in self.states.values(): |
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| 462 | state.runtime_init() |
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| 463 | |
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| 464 | def error(self): |
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| 465 | """Report error details.""" |
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| 466 | type, value, module, line, function = _exception_data() |
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| 467 | print >>sys.stderr, '%s: %s' % (type, value) |
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| 468 | print >>sys.stderr, 'input line %s' % (self.abs_line_number()) |
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| 469 | print >>sys.stderr, ('module %s, line %s, function %s' |
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| 470 | % (module, line, function)) |
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| 471 | |
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| 472 | def attach_observer(self, observer): |
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| 473 | """ |
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| 474 | The `observer` parameter is a function or bound method which takes two |
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| 475 | arguments, the source and offset of the current line. |
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| 476 | """ |
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| 477 | self.observers.append(observer) |
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| 478 | |
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| 479 | def detach_observer(self, observer): |
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| 480 | self.observers.remove(observer) |
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| 481 | |
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| 482 | def notify_observers(self): |
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| 483 | for observer in self.observers: |
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| 484 | try: |
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| 485 | info = self.input_lines.info(self.line_offset) |
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| 486 | except IndexError: |
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| 487 | info = (None, None) |
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| 488 | observer(*info) |
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| 489 | |
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| 490 | |
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| 491 | class State: |
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| 492 | |
---|
| 493 | """ |
---|
| 494 | State superclass. Contains a list of transitions, and transition methods. |
---|
| 495 | |
---|
| 496 | Transition methods all have the same signature. They take 3 parameters: |
---|
| 497 | |
---|
| 498 | - An `re` match object. ``match.string`` contains the matched input line, |
---|
| 499 | ``match.start()`` gives the start index of the match, and |
---|
| 500 | ``match.end()`` gives the end index. |
---|
| 501 | - A context object, whose meaning is application-defined (initial value |
---|
| 502 | ``None``). It can be used to store any information required by the state |
---|
| 503 | machine, and the retured context is passed on to the next transition |
---|
| 504 | method unchanged. |
---|
| 505 | - The name of the next state, a string, taken from the transitions list; |
---|
| 506 | normally it is returned unchanged, but it may be altered by the |
---|
| 507 | transition method if necessary. |
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| 508 | |
---|
| 509 | Transition methods all return a 3-tuple: |
---|
| 510 | |
---|
| 511 | - A context object, as (potentially) modified by the transition method. |
---|
| 512 | - The next state name (a return value of ``None`` means no state change). |
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| 513 | - The processing result, a list, which is accumulated by the state |
---|
| 514 | machine. |
---|
| 515 | |
---|
| 516 | Transition methods may raise an `EOFError` to cut processing short. |
---|
| 517 | |
---|
| 518 | There are two implicit transitions, and corresponding transition methods |
---|
| 519 | are defined: `bof()` handles the beginning-of-file, and `eof()` handles |
---|
| 520 | the end-of-file. These methods have non-standard signatures and return |
---|
| 521 | values. `bof()` returns the initial context and results, and may be used |
---|
| 522 | to return a header string, or do any other processing needed. `eof()` |
---|
| 523 | should handle any remaining context and wrap things up; it returns the |
---|
| 524 | final processing result. |
---|
| 525 | |
---|
| 526 | Typical applications need only subclass `State` (or a subclass), set the |
---|
| 527 | `patterns` and `initial_transitions` class attributes, and provide |
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| 528 | corresponding transition methods. The default object initialization will |
---|
| 529 | take care of constructing the list of transitions. |
---|
| 530 | """ |
---|
| 531 | |
---|
| 532 | patterns = None |
---|
| 533 | """ |
---|
| 534 | {Name: pattern} mapping, used by `make_transition()`. Each pattern may |
---|
| 535 | be a string or a compiled `re` pattern. Override in subclasses. |
---|
| 536 | """ |
---|
| 537 | |
---|
| 538 | initial_transitions = None |
---|
| 539 | """ |
---|
| 540 | A list of transitions to initialize when a `State` is instantiated. |
---|
| 541 | Each entry is either a transition name string, or a (transition name, next |
---|
| 542 | state name) pair. See `make_transitions()`. Override in subclasses. |
---|
| 543 | """ |
---|
| 544 | |
---|
| 545 | nested_sm = None |
---|
| 546 | """ |
---|
| 547 | The `StateMachine` class for handling nested processing. |
---|
| 548 | |
---|
| 549 | If left as ``None``, `nested_sm` defaults to the class of the state's |
---|
| 550 | controlling state machine. Override it in subclasses to avoid the default. |
---|
| 551 | """ |
---|
| 552 | |
---|
| 553 | nested_sm_kwargs = None |
---|
| 554 | """ |
---|
| 555 | Keyword arguments dictionary, passed to the `nested_sm` constructor. |
---|
| 556 | |
---|
| 557 | Two keys must have entries in the dictionary: |
---|
| 558 | |
---|
| 559 | - Key 'state_classes' must be set to a list of `State` classes. |
---|
| 560 | - Key 'initial_state' must be set to the name of the initial state class. |
---|
| 561 | |
---|
| 562 | If `nested_sm_kwargs` is left as ``None``, 'state_classes' defaults to the |
---|
| 563 | class of the current state, and 'initial_state' defaults to the name of |
---|
| 564 | the class of the current state. Override in subclasses to avoid the |
---|
| 565 | defaults. |
---|
| 566 | """ |
---|
| 567 | |
---|
| 568 | def __init__(self, state_machine, debug=0): |
---|
| 569 | """ |
---|
| 570 | Initialize a `State` object; make & add initial transitions. |
---|
| 571 | |
---|
| 572 | Parameters: |
---|
| 573 | |
---|
| 574 | - `statemachine`: the controlling `StateMachine` object. |
---|
| 575 | - `debug`: a boolean; produce verbose output if true (nonzero). |
---|
| 576 | """ |
---|
| 577 | |
---|
| 578 | self.transition_order = [] |
---|
| 579 | """A list of transition names in search order.""" |
---|
| 580 | |
---|
| 581 | self.transitions = {} |
---|
| 582 | """ |
---|
| 583 | A mapping of transition names to 3-tuples containing |
---|
| 584 | (compiled_pattern, transition_method, next_state_name). Initialized as |
---|
| 585 | an instance attribute dynamically (instead of as a class attribute) |
---|
| 586 | because it may make forward references to patterns and methods in this |
---|
| 587 | or other classes. |
---|
| 588 | """ |
---|
| 589 | |
---|
| 590 | self.add_initial_transitions() |
---|
| 591 | |
---|
| 592 | self.state_machine = state_machine |
---|
| 593 | """A reference to the controlling `StateMachine` object.""" |
---|
| 594 | |
---|
| 595 | self.debug = debug |
---|
| 596 | """Debugging mode on/off.""" |
---|
| 597 | |
---|
| 598 | if self.nested_sm is None: |
---|
| 599 | self.nested_sm = self.state_machine.__class__ |
---|
| 600 | if self.nested_sm_kwargs is None: |
---|
| 601 | self.nested_sm_kwargs = {'state_classes': [self.__class__], |
---|
| 602 | 'initial_state': self.__class__.__name__} |
---|
| 603 | |
---|
| 604 | def runtime_init(self): |
---|
| 605 | """ |
---|
| 606 | Initialize this `State` before running the state machine; called from |
---|
| 607 | `self.state_machine.run()`. |
---|
| 608 | """ |
---|
| 609 | pass |
---|
| 610 | |
---|
| 611 | def unlink(self): |
---|
| 612 | """Remove circular references to objects no longer required.""" |
---|
| 613 | self.state_machine = None |
---|
| 614 | |
---|
| 615 | def add_initial_transitions(self): |
---|
| 616 | """Make and add transitions listed in `self.initial_transitions`.""" |
---|
| 617 | if self.initial_transitions: |
---|
| 618 | names, transitions = self.make_transitions( |
---|
| 619 | self.initial_transitions) |
---|
| 620 | self.add_transitions(names, transitions) |
---|
| 621 | |
---|
| 622 | def add_transitions(self, names, transitions): |
---|
| 623 | """ |
---|
| 624 | Add a list of transitions to the start of the transition list. |
---|
| 625 | |
---|
| 626 | Parameters: |
---|
| 627 | |
---|
| 628 | - `names`: a list of transition names. |
---|
| 629 | - `transitions`: a mapping of names to transition tuples. |
---|
| 630 | |
---|
| 631 | Exceptions: `DuplicateTransitionError`, `UnknownTransitionError`. |
---|
| 632 | """ |
---|
| 633 | for name in names: |
---|
| 634 | if self.transitions.has_key(name): |
---|
| 635 | raise DuplicateTransitionError(name) |
---|
| 636 | if not transitions.has_key(name): |
---|
| 637 | raise UnknownTransitionError(name) |
---|
| 638 | self.transition_order[:0] = names |
---|
| 639 | self.transitions.update(transitions) |
---|
| 640 | |
---|
| 641 | def add_transition(self, name, transition): |
---|
| 642 | """ |
---|
| 643 | Add a transition to the start of the transition list. |
---|
| 644 | |
---|
| 645 | Parameter `transition`: a ready-made transition 3-tuple. |
---|
| 646 | |
---|
| 647 | Exception: `DuplicateTransitionError`. |
---|
| 648 | """ |
---|
| 649 | if self.transitions.has_key(name): |
---|
| 650 | raise DuplicateTransitionError(name) |
---|
| 651 | self.transition_order[:0] = [name] |
---|
| 652 | self.transitions[name] = transition |
---|
| 653 | |
---|
| 654 | def remove_transition(self, name): |
---|
| 655 | """ |
---|
| 656 | Remove a transition by `name`. |
---|
| 657 | |
---|
| 658 | Exception: `UnknownTransitionError`. |
---|
| 659 | """ |
---|
| 660 | try: |
---|
| 661 | del self.transitions[name] |
---|
| 662 | self.transition_order.remove(name) |
---|
| 663 | except: |
---|
| 664 | raise UnknownTransitionError(name) |
---|
| 665 | |
---|
| 666 | def make_transition(self, name, next_state=None): |
---|
| 667 | """ |
---|
| 668 | Make & return a transition tuple based on `name`. |
---|
| 669 | |
---|
| 670 | This is a convenience function to simplify transition creation. |
---|
| 671 | |
---|
| 672 | Parameters: |
---|
| 673 | |
---|
| 674 | - `name`: a string, the name of the transition pattern & method. This |
---|
| 675 | `State` object must have a method called '`name`', and a dictionary |
---|
| 676 | `self.patterns` containing a key '`name`'. |
---|
| 677 | - `next_state`: a string, the name of the next `State` object for this |
---|
| 678 | transition. A value of ``None`` (or absent) implies no state change |
---|
| 679 | (i.e., continue with the same state). |
---|
| 680 | |
---|
| 681 | Exceptions: `TransitionPatternNotFound`, `TransitionMethodNotFound`. |
---|
| 682 | """ |
---|
| 683 | if next_state is None: |
---|
| 684 | next_state = self.__class__.__name__ |
---|
| 685 | try: |
---|
| 686 | pattern = self.patterns[name] |
---|
| 687 | if not hasattr(pattern, 'match'): |
---|
| 688 | pattern = re.compile(pattern) |
---|
| 689 | except KeyError: |
---|
| 690 | raise TransitionPatternNotFound( |
---|
| 691 | '%s.patterns[%r]' % (self.__class__.__name__, name)) |
---|
| 692 | try: |
---|
| 693 | method = getattr(self, name) |
---|
| 694 | except AttributeError: |
---|
| 695 | raise TransitionMethodNotFound( |
---|
| 696 | '%s.%s' % (self.__class__.__name__, name)) |
---|
| 697 | return (pattern, method, next_state) |
---|
| 698 | |
---|
| 699 | def make_transitions(self, name_list): |
---|
| 700 | """ |
---|
| 701 | Return a list of transition names and a transition mapping. |
---|
| 702 | |
---|
| 703 | Parameter `name_list`: a list, where each entry is either a transition |
---|
| 704 | name string, or a 1- or 2-tuple (transition name, optional next state |
---|
| 705 | name). |
---|
| 706 | """ |
---|
| 707 | stringtype = type('') |
---|
| 708 | names = [] |
---|
| 709 | transitions = {} |
---|
| 710 | for namestate in name_list: |
---|
| 711 | if type(namestate) is stringtype: |
---|
| 712 | transitions[namestate] = self.make_transition(namestate) |
---|
| 713 | names.append(namestate) |
---|
| 714 | else: |
---|
| 715 | transitions[namestate[0]] = self.make_transition(*namestate) |
---|
| 716 | names.append(namestate[0]) |
---|
| 717 | return names, transitions |
---|
| 718 | |
---|
| 719 | def no_match(self, context, transitions): |
---|
| 720 | """ |
---|
| 721 | Called when there is no match from `StateMachine.check_line()`. |
---|
| 722 | |
---|
| 723 | Return the same values returned by transition methods: |
---|
| 724 | |
---|
| 725 | - context: unchanged; |
---|
| 726 | - next state name: ``None``; |
---|
| 727 | - empty result list. |
---|
| 728 | |
---|
| 729 | Override in subclasses to catch this event. |
---|
| 730 | """ |
---|
| 731 | return context, None, [] |
---|
| 732 | |
---|
| 733 | def bof(self, context): |
---|
| 734 | """ |
---|
| 735 | Handle beginning-of-file. Return unchanged `context`, empty result. |
---|
| 736 | |
---|
| 737 | Override in subclasses. |
---|
| 738 | |
---|
| 739 | Parameter `context`: application-defined storage. |
---|
| 740 | """ |
---|
| 741 | return context, [] |
---|
| 742 | |
---|
| 743 | def eof(self, context): |
---|
| 744 | """ |
---|
| 745 | Handle end-of-file. Return empty result. |
---|
| 746 | |
---|
| 747 | Override in subclasses. |
---|
| 748 | |
---|
| 749 | Parameter `context`: application-defined storage. |
---|
| 750 | """ |
---|
| 751 | return [] |
---|
| 752 | |
---|
| 753 | def nop(self, match, context, next_state): |
---|
| 754 | """ |
---|
| 755 | A "do nothing" transition method. |
---|
| 756 | |
---|
| 757 | Return unchanged `context` & `next_state`, empty result. Useful for |
---|
| 758 | simple state changes (actionless transitions). |
---|
| 759 | """ |
---|
| 760 | return context, next_state, [] |
---|
| 761 | |
---|
| 762 | |
---|
| 763 | class StateMachineWS(StateMachine): |
---|
| 764 | |
---|
| 765 | """ |
---|
| 766 | `StateMachine` subclass specialized for whitespace recognition. |
---|
| 767 | |
---|
| 768 | There are three methods provided for extracting indented text blocks: |
---|
| 769 | |
---|
| 770 | - `get_indented()`: use when the indent is unknown. |
---|
| 771 | - `get_known_indented()`: use when the indent is known for all lines. |
---|
| 772 | - `get_first_known_indented()`: use when only the first line's indent is |
---|
| 773 | known. |
---|
| 774 | """ |
---|
| 775 | |
---|
| 776 | def get_indented(self, until_blank=0, strip_indent=1): |
---|
| 777 | """ |
---|
| 778 | Return a block of indented lines of text, and info. |
---|
| 779 | |
---|
| 780 | Extract an indented block where the indent is unknown for all lines. |
---|
| 781 | |
---|
| 782 | :Parameters: |
---|
| 783 | - `until_blank`: Stop collecting at the first blank line if true |
---|
| 784 | (1). |
---|
| 785 | - `strip_indent`: Strip common leading indent if true (1, |
---|
| 786 | default). |
---|
| 787 | |
---|
| 788 | :Return: |
---|
| 789 | - the indented block (a list of lines of text), |
---|
| 790 | - its indent, |
---|
| 791 | - its first line offset from BOF, and |
---|
| 792 | - whether or not it finished with a blank line. |
---|
| 793 | """ |
---|
| 794 | offset = self.abs_line_offset() |
---|
| 795 | indented, indent, blank_finish = self.input_lines.get_indented( |
---|
| 796 | self.line_offset, until_blank, strip_indent) |
---|
| 797 | if indented: |
---|
| 798 | self.next_line(len(indented) - 1) # advance to last indented line |
---|
| 799 | while indented and not indented[0].strip(): |
---|
| 800 | indented.trim_start() |
---|
| 801 | offset += 1 |
---|
| 802 | return indented, indent, offset, blank_finish |
---|
| 803 | |
---|
| 804 | def get_known_indented(self, indent, until_blank=0, strip_indent=1): |
---|
| 805 | """ |
---|
| 806 | Return an indented block and info. |
---|
| 807 | |
---|
| 808 | Extract an indented block where the indent is known for all lines. |
---|
| 809 | Starting with the current line, extract the entire text block with at |
---|
| 810 | least `indent` indentation (which must be whitespace, except for the |
---|
| 811 | first line). |
---|
| 812 | |
---|
| 813 | :Parameters: |
---|
| 814 | - `indent`: The number of indent columns/characters. |
---|
| 815 | - `until_blank`: Stop collecting at the first blank line if true |
---|
| 816 | (1). |
---|
| 817 | - `strip_indent`: Strip `indent` characters of indentation if true |
---|
| 818 | (1, default). |
---|
| 819 | |
---|
| 820 | :Return: |
---|
| 821 | - the indented block, |
---|
| 822 | - its first line offset from BOF, and |
---|
| 823 | - whether or not it finished with a blank line. |
---|
| 824 | """ |
---|
| 825 | offset = self.abs_line_offset() |
---|
| 826 | indented, indent, blank_finish = self.input_lines.get_indented( |
---|
| 827 | self.line_offset, until_blank, strip_indent, |
---|
| 828 | block_indent=indent) |
---|
| 829 | self.next_line(len(indented) - 1) # advance to last indented line |
---|
| 830 | while indented and not indented[0].strip(): |
---|
| 831 | indented.trim_start() |
---|
| 832 | offset += 1 |
---|
| 833 | return indented, offset, blank_finish |
---|
| 834 | |
---|
| 835 | def get_first_known_indented(self, indent, until_blank=0, strip_indent=1, |
---|
| 836 | strip_top=1): |
---|
| 837 | """ |
---|
| 838 | Return an indented block and info. |
---|
| 839 | |
---|
| 840 | Extract an indented block where the indent is known for the first line |
---|
| 841 | and unknown for all other lines. |
---|
| 842 | |
---|
| 843 | :Parameters: |
---|
| 844 | - `indent`: The first line's indent (# of columns/characters). |
---|
| 845 | - `until_blank`: Stop collecting at the first blank line if true |
---|
| 846 | (1). |
---|
| 847 | - `strip_indent`: Strip `indent` characters of indentation if true |
---|
| 848 | (1, default). |
---|
| 849 | - `strip_top`: Strip blank lines from the beginning of the block. |
---|
| 850 | |
---|
| 851 | :Return: |
---|
| 852 | - the indented block, |
---|
| 853 | - its indent, |
---|
| 854 | - its first line offset from BOF, and |
---|
| 855 | - whether or not it finished with a blank line. |
---|
| 856 | """ |
---|
| 857 | offset = self.abs_line_offset() |
---|
| 858 | indented, indent, blank_finish = self.input_lines.get_indented( |
---|
| 859 | self.line_offset, until_blank, strip_indent, |
---|
| 860 | first_indent=indent) |
---|
| 861 | self.next_line(len(indented) - 1) # advance to last indented line |
---|
| 862 | if strip_top: |
---|
| 863 | while indented and not indented[0].strip(): |
---|
| 864 | indented.trim_start() |
---|
| 865 | offset += 1 |
---|
| 866 | return indented, indent, offset, blank_finish |
---|
| 867 | |
---|
| 868 | |
---|
| 869 | class StateWS(State): |
---|
| 870 | |
---|
| 871 | """ |
---|
| 872 | State superclass specialized for whitespace (blank lines & indents). |
---|
| 873 | |
---|
| 874 | Use this class with `StateMachineWS`. The transitions 'blank' (for blank |
---|
| 875 | lines) and 'indent' (for indented text blocks) are added automatically, |
---|
| 876 | before any other transitions. The transition method `blank()` handles |
---|
| 877 | blank lines and `indent()` handles nested indented blocks. Indented |
---|
| 878 | blocks trigger a new state machine to be created by `indent()` and run. |
---|
| 879 | The class of the state machine to be created is in `indent_sm`, and the |
---|
| 880 | constructor keyword arguments are in the dictionary `indent_sm_kwargs`. |
---|
| 881 | |
---|
| 882 | The methods `known_indent()` and `firstknown_indent()` are provided for |
---|
| 883 | indented blocks where the indent (all lines' and first line's only, |
---|
| 884 | respectively) is known to the transition method, along with the attributes |
---|
| 885 | `known_indent_sm` and `known_indent_sm_kwargs`. Neither transition method |
---|
| 886 | is triggered automatically. |
---|
| 887 | """ |
---|
| 888 | |
---|
| 889 | indent_sm = None |
---|
| 890 | """ |
---|
| 891 | The `StateMachine` class handling indented text blocks. |
---|
| 892 | |
---|
| 893 | If left as ``None``, `indent_sm` defaults to the value of |
---|
| 894 | `State.nested_sm`. Override it in subclasses to avoid the default. |
---|
| 895 | """ |
---|
| 896 | |
---|
| 897 | indent_sm_kwargs = None |
---|
| 898 | """ |
---|
| 899 | Keyword arguments dictionary, passed to the `indent_sm` constructor. |
---|
| 900 | |
---|
| 901 | If left as ``None``, `indent_sm_kwargs` defaults to the value of |
---|
| 902 | `State.nested_sm_kwargs`. Override it in subclasses to avoid the default. |
---|
| 903 | """ |
---|
| 904 | |
---|
| 905 | known_indent_sm = None |
---|
| 906 | """ |
---|
| 907 | The `StateMachine` class handling known-indented text blocks. |
---|
| 908 | |
---|
| 909 | If left as ``None``, `known_indent_sm` defaults to the value of |
---|
| 910 | `indent_sm`. Override it in subclasses to avoid the default. |
---|
| 911 | """ |
---|
| 912 | |
---|
| 913 | known_indent_sm_kwargs = None |
---|
| 914 | """ |
---|
| 915 | Keyword arguments dictionary, passed to the `known_indent_sm` constructor. |
---|
| 916 | |
---|
| 917 | If left as ``None``, `known_indent_sm_kwargs` defaults to the value of |
---|
| 918 | `indent_sm_kwargs`. Override it in subclasses to avoid the default. |
---|
| 919 | """ |
---|
| 920 | |
---|
| 921 | ws_patterns = {'blank': ' *$', |
---|
| 922 | 'indent': ' +'} |
---|
| 923 | """Patterns for default whitespace transitions. May be overridden in |
---|
| 924 | subclasses.""" |
---|
| 925 | |
---|
| 926 | ws_initial_transitions = ('blank', 'indent') |
---|
| 927 | """Default initial whitespace transitions, added before those listed in |
---|
| 928 | `State.initial_transitions`. May be overridden in subclasses.""" |
---|
| 929 | |
---|
| 930 | def __init__(self, state_machine, debug=0): |
---|
| 931 | """ |
---|
| 932 | Initialize a `StateSM` object; extends `State.__init__()`. |
---|
| 933 | |
---|
| 934 | Check for indent state machine attributes, set defaults if not set. |
---|
| 935 | """ |
---|
| 936 | State.__init__(self, state_machine, debug) |
---|
| 937 | if self.indent_sm is None: |
---|
| 938 | self.indent_sm = self.nested_sm |
---|
| 939 | if self.indent_sm_kwargs is None: |
---|
| 940 | self.indent_sm_kwargs = self.nested_sm_kwargs |
---|
| 941 | if self.known_indent_sm is None: |
---|
| 942 | self.known_indent_sm = self.indent_sm |
---|
| 943 | if self.known_indent_sm_kwargs is None: |
---|
| 944 | self.known_indent_sm_kwargs = self.indent_sm_kwargs |
---|
| 945 | |
---|
| 946 | def add_initial_transitions(self): |
---|
| 947 | """ |
---|
| 948 | Add whitespace-specific transitions before those defined in subclass. |
---|
| 949 | |
---|
| 950 | Extends `State.add_initial_transitions()`. |
---|
| 951 | """ |
---|
| 952 | State.add_initial_transitions(self) |
---|
| 953 | if self.patterns is None: |
---|
| 954 | self.patterns = {} |
---|
| 955 | self.patterns.update(self.ws_patterns) |
---|
| 956 | names, transitions = self.make_transitions( |
---|
| 957 | self.ws_initial_transitions) |
---|
| 958 | self.add_transitions(names, transitions) |
---|
| 959 | |
---|
| 960 | def blank(self, match, context, next_state): |
---|
| 961 | """Handle blank lines. Does nothing. Override in subclasses.""" |
---|
| 962 | return self.nop(match, context, next_state) |
---|
| 963 | |
---|
| 964 | def indent(self, match, context, next_state): |
---|
| 965 | """ |
---|
| 966 | Handle an indented text block. Extend or override in subclasses. |
---|
| 967 | |
---|
| 968 | Recursively run the registered state machine for indented blocks |
---|
| 969 | (`self.indent_sm`). |
---|
| 970 | """ |
---|
| 971 | indented, indent, line_offset, blank_finish = \ |
---|
| 972 | self.state_machine.get_indented() |
---|
| 973 | sm = self.indent_sm(debug=self.debug, **self.indent_sm_kwargs) |
---|
| 974 | results = sm.run(indented, input_offset=line_offset) |
---|
| 975 | return context, next_state, results |
---|
| 976 | |
---|
| 977 | def known_indent(self, match, context, next_state): |
---|
| 978 | """ |
---|
| 979 | Handle a known-indent text block. Extend or override in subclasses. |
---|
| 980 | |
---|
| 981 | Recursively run the registered state machine for known-indent indented |
---|
| 982 | blocks (`self.known_indent_sm`). The indent is the length of the |
---|
| 983 | match, ``match.end()``. |
---|
| 984 | """ |
---|
| 985 | indented, line_offset, blank_finish = \ |
---|
| 986 | self.state_machine.get_known_indented(match.end()) |
---|
| 987 | sm = self.known_indent_sm(debug=self.debug, |
---|
| 988 | **self.known_indent_sm_kwargs) |
---|
| 989 | results = sm.run(indented, input_offset=line_offset) |
---|
| 990 | return context, next_state, results |
---|
| 991 | |
---|
| 992 | def first_known_indent(self, match, context, next_state): |
---|
| 993 | """ |
---|
| 994 | Handle an indented text block (first line's indent known). |
---|
| 995 | |
---|
| 996 | Extend or override in subclasses. |
---|
| 997 | |
---|
| 998 | Recursively run the registered state machine for known-indent indented |
---|
| 999 | blocks (`self.known_indent_sm`). The indent is the length of the |
---|
| 1000 | match, ``match.end()``. |
---|
| 1001 | """ |
---|
| 1002 | indented, line_offset, blank_finish = \ |
---|
| 1003 | self.state_machine.get_first_known_indented(match.end()) |
---|
| 1004 | sm = self.known_indent_sm(debug=self.debug, |
---|
| 1005 | **self.known_indent_sm_kwargs) |
---|
| 1006 | results = sm.run(indented, input_offset=line_offset) |
---|
| 1007 | return context, next_state, results |
---|
| 1008 | |
---|
| 1009 | |
---|
| 1010 | class _SearchOverride: |
---|
| 1011 | |
---|
| 1012 | """ |
---|
| 1013 | Mix-in class to override `StateMachine` regular expression behavior. |
---|
| 1014 | |
---|
| 1015 | Changes regular expression matching, from the default `re.match()` |
---|
| 1016 | (succeeds only if the pattern matches at the start of `self.line`) to |
---|
| 1017 | `re.search()` (succeeds if the pattern matches anywhere in `self.line`). |
---|
| 1018 | When subclassing a `StateMachine`, list this class **first** in the |
---|
| 1019 | inheritance list of the class definition. |
---|
| 1020 | """ |
---|
| 1021 | |
---|
| 1022 | def match(self, pattern): |
---|
| 1023 | """ |
---|
| 1024 | Return the result of a regular expression search. |
---|
| 1025 | |
---|
| 1026 | Overrides `StateMachine.match()`. |
---|
| 1027 | |
---|
| 1028 | Parameter `pattern`: `re` compiled regular expression. |
---|
| 1029 | """ |
---|
| 1030 | return pattern.search(self.line) |
---|
| 1031 | |
---|
| 1032 | |
---|
| 1033 | class SearchStateMachine(_SearchOverride, StateMachine): |
---|
| 1034 | """`StateMachine` which uses `re.search()` instead of `re.match()`.""" |
---|
| 1035 | pass |
---|
| 1036 | |
---|
| 1037 | |
---|
| 1038 | class SearchStateMachineWS(_SearchOverride, StateMachineWS): |
---|
| 1039 | """`StateMachineWS` which uses `re.search()` instead of `re.match()`.""" |
---|
| 1040 | pass |
---|
| 1041 | |
---|
| 1042 | |
---|
| 1043 | class ViewList: |
---|
| 1044 | |
---|
| 1045 | """ |
---|
| 1046 | List with extended functionality: slices of ViewList objects are child |
---|
| 1047 | lists, linked to their parents. Changes made to a child list also affect |
---|
| 1048 | the parent list. A child list is effectively a "view" (in the SQL sense) |
---|
| 1049 | of the parent list. Changes to parent lists, however, do *not* affect |
---|
| 1050 | active child lists. If a parent list is changed, any active child lists |
---|
| 1051 | should be recreated. |
---|
| 1052 | |
---|
| 1053 | The start and end of the slice can be trimmed using the `trim_start()` and |
---|
| 1054 | `trim_end()` methods, without affecting the parent list. The link between |
---|
| 1055 | child and parent lists can be broken by calling `disconnect()` on the |
---|
| 1056 | child list. |
---|
| 1057 | |
---|
| 1058 | Also, ViewList objects keep track of the source & offset of each item. |
---|
| 1059 | This information is accessible via the `source()`, `offset()`, and |
---|
| 1060 | `info()` methods. |
---|
| 1061 | """ |
---|
| 1062 | |
---|
| 1063 | def __init__(self, initlist=None, source=None, items=None, |
---|
| 1064 | parent=None, parent_offset=None): |
---|
| 1065 | self.data = [] |
---|
| 1066 | """The actual list of data, flattened from various sources.""" |
---|
| 1067 | |
---|
| 1068 | self.items = [] |
---|
| 1069 | """A list of (source, offset) pairs, same length as `self.data`: the |
---|
| 1070 | source of each line and the offset of each line from the beginning of |
---|
| 1071 | its source.""" |
---|
| 1072 | |
---|
| 1073 | self.parent = parent |
---|
| 1074 | """The parent list.""" |
---|
| 1075 | |
---|
| 1076 | self.parent_offset = parent_offset |
---|
| 1077 | """Offset of this list from the beginning of the parent list.""" |
---|
| 1078 | |
---|
| 1079 | if isinstance(initlist, ViewList): |
---|
| 1080 | self.data = initlist.data[:] |
---|
| 1081 | self.items = initlist.items[:] |
---|
| 1082 | elif initlist is not None: |
---|
| 1083 | self.data = list(initlist) |
---|
| 1084 | if items: |
---|
| 1085 | self.items = items |
---|
| 1086 | else: |
---|
| 1087 | self.items = [(source, i) for i in range(len(initlist))] |
---|
| 1088 | assert len(self.data) == len(self.items), 'data mismatch' |
---|
| 1089 | |
---|
| 1090 | def __str__(self): |
---|
| 1091 | return str(self.data) |
---|
| 1092 | |
---|
| 1093 | def __repr__(self): |
---|
| 1094 | return '%s(%s, items=%s)' % (self.__class__.__name__, |
---|
| 1095 | self.data, self.items) |
---|
| 1096 | |
---|
| 1097 | def __lt__(self, other): return self.data < self.__cast(other) |
---|
| 1098 | def __le__(self, other): return self.data <= self.__cast(other) |
---|
| 1099 | def __eq__(self, other): return self.data == self.__cast(other) |
---|
| 1100 | def __ne__(self, other): return self.data != self.__cast(other) |
---|
| 1101 | def __gt__(self, other): return self.data > self.__cast(other) |
---|
| 1102 | def __ge__(self, other): return self.data >= self.__cast(other) |
---|
| 1103 | def __cmp__(self, other): return cmp(self.data, self.__cast(other)) |
---|
| 1104 | |
---|
| 1105 | def __cast(self, other): |
---|
| 1106 | if isinstance(other, ViewList): |
---|
| 1107 | return other.data |
---|
| 1108 | else: |
---|
| 1109 | return other |
---|
| 1110 | |
---|
| 1111 | def __contains__(self, item): return item in self.data |
---|
| 1112 | def __len__(self): return len(self.data) |
---|
| 1113 | |
---|
| 1114 | # The __getitem__()/__setitem__() methods check whether the index |
---|
| 1115 | # is a slice first, since native list objects start supporting |
---|
| 1116 | # them directly in Python 2.3 (no exception is raised when |
---|
| 1117 | # indexing a list with a slice object; they just work). |
---|
| 1118 | |
---|
| 1119 | def __getitem__(self, i): |
---|
| 1120 | if isinstance(i, types.SliceType): |
---|
| 1121 | assert i.step in (None, 1), 'cannot handle slice with stride' |
---|
| 1122 | return self.__class__(self.data[i.start:i.stop], |
---|
| 1123 | items=self.items[i.start:i.stop], |
---|
| 1124 | parent=self, parent_offset=i.start) |
---|
| 1125 | else: |
---|
| 1126 | return self.data[i] |
---|
| 1127 | |
---|
| 1128 | def __setitem__(self, i, item): |
---|
| 1129 | if isinstance(i, types.SliceType): |
---|
| 1130 | assert i.step in (None, 1), 'cannot handle slice with stride' |
---|
| 1131 | if not isinstance(item, ViewList): |
---|
| 1132 | raise TypeError('assigning non-ViewList to ViewList slice') |
---|
| 1133 | self.data[i.start:i.stop] = item.data |
---|
| 1134 | self.items[i.start:i.stop] = item.items |
---|
| 1135 | assert len(self.data) == len(self.items), 'data mismatch' |
---|
| 1136 | if self.parent: |
---|
| 1137 | self.parent[i.start + self.parent_offset |
---|
| 1138 | : i.stop + self.parent_offset] = item |
---|
| 1139 | else: |
---|
| 1140 | self.data[i] = item |
---|
| 1141 | if self.parent: |
---|
| 1142 | self.parent[i + self.parent_offset] = item |
---|
| 1143 | |
---|
| 1144 | def __delitem__(self, i): |
---|
| 1145 | try: |
---|
| 1146 | del self.data[i] |
---|
| 1147 | del self.items[i] |
---|
| 1148 | if self.parent: |
---|
| 1149 | del self.parent[i + self.parent_offset] |
---|
| 1150 | except TypeError: |
---|
| 1151 | assert i.step is None, 'cannot handle slice with stride' |
---|
| 1152 | del self.data[i.start:i.stop] |
---|
| 1153 | del self.items[i.start:i.stop] |
---|
| 1154 | if self.parent: |
---|
| 1155 | del self.parent[i.start + self.parent_offset |
---|
| 1156 | : i.stop + self.parent_offset] |
---|
| 1157 | |
---|
| 1158 | def __add__(self, other): |
---|
| 1159 | if isinstance(other, ViewList): |
---|
| 1160 | return self.__class__(self.data + other.data, |
---|
| 1161 | items=(self.items + other.items)) |
---|
| 1162 | else: |
---|
| 1163 | raise TypeError('adding non-ViewList to a ViewList') |
---|
| 1164 | |
---|
| 1165 | def __radd__(self, other): |
---|
| 1166 | if isinstance(other, ViewList): |
---|
| 1167 | return self.__class__(other.data + self.data, |
---|
| 1168 | items=(other.items + self.items)) |
---|
| 1169 | else: |
---|
| 1170 | raise TypeError('adding ViewList to a non-ViewList') |
---|
| 1171 | |
---|
| 1172 | def __iadd__(self, other): |
---|
| 1173 | if isinstance(other, ViewList): |
---|
| 1174 | self.data += other.data |
---|
| 1175 | else: |
---|
| 1176 | raise TypeError('argument to += must be a ViewList') |
---|
| 1177 | return self |
---|
| 1178 | |
---|
| 1179 | def __mul__(self, n): |
---|
| 1180 | return self.__class__(self.data * n, items=(self.items * n)) |
---|
| 1181 | |
---|
| 1182 | __rmul__ = __mul__ |
---|
| 1183 | |
---|
| 1184 | def __imul__(self, n): |
---|
| 1185 | self.data *= n |
---|
| 1186 | self.items *= n |
---|
| 1187 | return self |
---|
| 1188 | |
---|
| 1189 | def extend(self, other): |
---|
| 1190 | if not isinstance(other, ViewList): |
---|
| 1191 | raise TypeError('extending a ViewList with a non-ViewList') |
---|
| 1192 | if self.parent: |
---|
| 1193 | self.parent.insert(len(self.data) + self.parent_offset, other) |
---|
| 1194 | self.data.extend(other.data) |
---|
| 1195 | self.items.extend(other.items) |
---|
| 1196 | |
---|
| 1197 | def append(self, item, source=None, offset=0): |
---|
| 1198 | if source is None: |
---|
| 1199 | self.extend(item) |
---|
| 1200 | else: |
---|
| 1201 | if self.parent: |
---|
| 1202 | self.parent.insert(len(self.data) + self.parent_offset, item, |
---|
| 1203 | source, offset) |
---|
| 1204 | self.data.append(item) |
---|
| 1205 | self.items.append((source, offset)) |
---|
| 1206 | |
---|
| 1207 | def insert(self, i, item, source=None, offset=0): |
---|
| 1208 | if source is None: |
---|
| 1209 | if not isinstance(item, ViewList): |
---|
| 1210 | raise TypeError('inserting non-ViewList with no source given') |
---|
| 1211 | self.data[i:i] = item.data |
---|
| 1212 | self.items[i:i] = item.items |
---|
| 1213 | if self.parent: |
---|
| 1214 | index = (len(self.data) + i) % len(self.data) |
---|
| 1215 | self.parent.insert(index + self.parent_offset, item) |
---|
| 1216 | else: |
---|
| 1217 | self.data.insert(i, item) |
---|
| 1218 | self.items.insert(i, (source, offset)) |
---|
| 1219 | if self.parent: |
---|
| 1220 | index = (len(self.data) + i) % len(self.data) |
---|
| 1221 | self.parent.insert(index + self.parent_offset, item, |
---|
| 1222 | source, offset) |
---|
| 1223 | |
---|
| 1224 | def pop(self, i=-1): |
---|
| 1225 | if self.parent: |
---|
| 1226 | index = (len(self.data) + i) % len(self.data) |
---|
| 1227 | self.parent.pop(index + self.parent_offset) |
---|
| 1228 | self.items.pop(i) |
---|
| 1229 | return self.data.pop(i) |
---|
| 1230 | |
---|
| 1231 | def trim_start(self, n=1): |
---|
| 1232 | """ |
---|
| 1233 | Remove items from the start of the list, without touching the parent. |
---|
| 1234 | """ |
---|
| 1235 | if n > len(self.data): |
---|
| 1236 | raise IndexError("Size of trim too large; can't trim %s items " |
---|
| 1237 | "from a list of size %s." % (n, len(self.data))) |
---|
| 1238 | elif n < 0: |
---|
| 1239 | raise IndexError('Trim size must be >= 0.') |
---|
| 1240 | del self.data[:n] |
---|
| 1241 | del self.items[:n] |
---|
| 1242 | if self.parent: |
---|
| 1243 | self.parent_offset += n |
---|
| 1244 | |
---|
| 1245 | def trim_end(self, n=1): |
---|
| 1246 | """ |
---|
| 1247 | Remove items from the end of the list, without touching the parent. |
---|
| 1248 | """ |
---|
| 1249 | if n > len(self.data): |
---|
| 1250 | raise IndexError("Size of trim too large; can't trim %s items " |
---|
| 1251 | "from a list of size %s." % (n, len(self.data))) |
---|
| 1252 | elif n < 0: |
---|
| 1253 | raise IndexError('Trim size must be >= 0.') |
---|
| 1254 | del self.data[-n:] |
---|
| 1255 | del self.items[-n:] |
---|
| 1256 | |
---|
| 1257 | def remove(self, item): |
---|
| 1258 | index = self.index(item) |
---|
| 1259 | del self[index] |
---|
| 1260 | |
---|
| 1261 | def count(self, item): return self.data.count(item) |
---|
| 1262 | def index(self, item): return self.data.index(item) |
---|
| 1263 | |
---|
| 1264 | def reverse(self): |
---|
| 1265 | self.data.reverse() |
---|
| 1266 | self.items.reverse() |
---|
| 1267 | self.parent = None |
---|
| 1268 | |
---|
| 1269 | def sort(self, *args): |
---|
| 1270 | tmp = zip(self.data, self.items) |
---|
| 1271 | tmp.sort(*args) |
---|
| 1272 | self.data = [entry[0] for entry in tmp] |
---|
| 1273 | self.items = [entry[1] for entry in tmp] |
---|
| 1274 | self.parent = None |
---|
| 1275 | |
---|
| 1276 | def info(self, i): |
---|
| 1277 | """Return source & offset for index `i`.""" |
---|
| 1278 | try: |
---|
| 1279 | return self.items[i] |
---|
| 1280 | except IndexError: |
---|
| 1281 | if i == len(self.data): # Just past the end |
---|
| 1282 | return self.items[i - 1][0], None |
---|
| 1283 | else: |
---|
| 1284 | raise |
---|
| 1285 | |
---|
| 1286 | def source(self, i): |
---|
| 1287 | """Return source for index `i`.""" |
---|
| 1288 | return self.info(i)[0] |
---|
| 1289 | |
---|
| 1290 | def offset(self, i): |
---|
| 1291 | """Return offset for index `i`.""" |
---|
| 1292 | return self.info(i)[1] |
---|
| 1293 | |
---|
| 1294 | def disconnect(self): |
---|
| 1295 | """Break link between this list and parent list.""" |
---|
| 1296 | self.parent = None |
---|
| 1297 | |
---|
| 1298 | |
---|
| 1299 | class StringList(ViewList): |
---|
| 1300 | |
---|
| 1301 | """A `ViewList` with string-specific methods.""" |
---|
| 1302 | |
---|
| 1303 | def trim_left(self, length, start=0, end=sys.maxint): |
---|
| 1304 | """ |
---|
| 1305 | Trim `length` characters off the beginning of each item, in-place, |
---|
| 1306 | from index `start` to `end`. No whitespace-checking is done on the |
---|
| 1307 | trimmed text. Does not affect slice parent. |
---|
| 1308 | """ |
---|
| 1309 | self.data[start:end] = [line[length:] |
---|
| 1310 | for line in self.data[start:end]] |
---|
| 1311 | |
---|
| 1312 | def get_text_block(self, start, flush_left=0): |
---|
| 1313 | """ |
---|
| 1314 | Return a contiguous block of text. |
---|
| 1315 | |
---|
| 1316 | If `flush_left` is true, raise `UnexpectedIndentationError` if an |
---|
| 1317 | indented line is encountered before the text block ends (with a blank |
---|
| 1318 | line). |
---|
| 1319 | """ |
---|
| 1320 | end = start |
---|
| 1321 | last = len(self.data) |
---|
| 1322 | while end < last: |
---|
| 1323 | line = self.data[end] |
---|
| 1324 | if not line.strip(): |
---|
| 1325 | break |
---|
| 1326 | if flush_left and (line[0] == ' '): |
---|
| 1327 | source, offset = self.info(end) |
---|
| 1328 | raise UnexpectedIndentationError(self[start:end], source, |
---|
| 1329 | offset + 1) |
---|
| 1330 | end += 1 |
---|
| 1331 | return self[start:end] |
---|
| 1332 | |
---|
| 1333 | def get_indented(self, start=0, until_blank=0, strip_indent=1, |
---|
| 1334 | block_indent=None, first_indent=None): |
---|
| 1335 | """ |
---|
| 1336 | Extract and return a StringList of indented lines of text. |
---|
| 1337 | |
---|
| 1338 | Collect all lines with indentation, determine the minimum indentation, |
---|
| 1339 | remove the minimum indentation from all indented lines (unless |
---|
| 1340 | `strip_indent` is false), and return them. All lines up to but not |
---|
| 1341 | including the first unindented line will be returned. |
---|
| 1342 | |
---|
| 1343 | :Parameters: |
---|
| 1344 | - `start`: The index of the first line to examine. |
---|
| 1345 | - `until_blank`: Stop collecting at the first blank line if true. |
---|
| 1346 | - `strip_indent`: Strip common leading indent if true (default). |
---|
| 1347 | - `block_indent`: The indent of the entire block, if known. |
---|
| 1348 | - `first_indent`: The indent of the first line, if known. |
---|
| 1349 | |
---|
| 1350 | :Return: |
---|
| 1351 | - a StringList of indented lines with mininum indent removed; |
---|
| 1352 | - the amount of the indent; |
---|
| 1353 | - a boolean: did the indented block finish with a blank line or EOF? |
---|
| 1354 | """ |
---|
| 1355 | indent = block_indent # start with None if unknown |
---|
| 1356 | end = start |
---|
| 1357 | if block_indent is not None and first_indent is None: |
---|
| 1358 | first_indent = block_indent |
---|
| 1359 | if first_indent is not None: |
---|
| 1360 | end += 1 |
---|
| 1361 | last = len(self.data) |
---|
| 1362 | while end < last: |
---|
| 1363 | line = self.data[end] |
---|
| 1364 | if line and (line[0] != ' ' |
---|
| 1365 | or (block_indent is not None |
---|
| 1366 | and line[:block_indent].strip())): |
---|
| 1367 | # Line not indented or insufficiently indented. |
---|
| 1368 | # Block finished properly iff the last indented line blank: |
---|
| 1369 | blank_finish = ((end > start) |
---|
| 1370 | and not self.data[end - 1].strip()) |
---|
| 1371 | break |
---|
| 1372 | stripped = line.lstrip() |
---|
| 1373 | if not stripped: # blank line |
---|
| 1374 | if until_blank: |
---|
| 1375 | blank_finish = 1 |
---|
| 1376 | break |
---|
| 1377 | elif block_indent is None: |
---|
| 1378 | line_indent = len(line) - len(stripped) |
---|
| 1379 | if indent is None: |
---|
| 1380 | indent = line_indent |
---|
| 1381 | else: |
---|
| 1382 | indent = min(indent, line_indent) |
---|
| 1383 | end += 1 |
---|
| 1384 | else: |
---|
| 1385 | blank_finish = 1 # block ends at end of lines |
---|
| 1386 | block = self[start:end] |
---|
| 1387 | if first_indent is not None and block: |
---|
| 1388 | block.data[0] = block.data[0][first_indent:] |
---|
| 1389 | if indent and strip_indent: |
---|
| 1390 | block.trim_left(indent, start=(first_indent is not None)) |
---|
| 1391 | return block, indent or 0, blank_finish |
---|
| 1392 | |
---|
| 1393 | def get_2D_block(self, top, left, bottom, right, strip_indent=1): |
---|
| 1394 | block = self[top:bottom] |
---|
| 1395 | indent = right |
---|
| 1396 | for i in range(len(block.data)): |
---|
| 1397 | block.data[i] = line = block.data[i][left:right].rstrip() |
---|
| 1398 | if line: |
---|
| 1399 | indent = min(indent, len(line) - len(line.lstrip())) |
---|
| 1400 | if strip_indent and 0 < indent < right: |
---|
| 1401 | block.data = [line[indent:] for line in block.data] |
---|
| 1402 | return block |
---|
| 1403 | |
---|
| 1404 | def pad_double_width(self, pad_char): |
---|
| 1405 | """ |
---|
| 1406 | Pad all double-width characters in self by appending `pad_char` to each. |
---|
| 1407 | For East Asian language support. |
---|
| 1408 | """ |
---|
| 1409 | if hasattr(unicodedata, 'east_asian_width'): |
---|
| 1410 | east_asian_width = unicodedata.east_asian_width |
---|
| 1411 | else: |
---|
| 1412 | return # new in Python 2.4 |
---|
| 1413 | for i in range(len(self.data)): |
---|
| 1414 | line = self.data[i] |
---|
| 1415 | if isinstance(line, types.UnicodeType): |
---|
| 1416 | new = [] |
---|
| 1417 | for char in line: |
---|
| 1418 | new.append(char) |
---|
| 1419 | if east_asian_width(char) in 'WF': # 'W'ide & 'F'ull-width |
---|
| 1420 | new.append(pad_char) |
---|
| 1421 | self.data[i] = ''.join(new) |
---|
| 1422 | |
---|
| 1423 | def replace(self, old, new): |
---|
| 1424 | """Replace all occurrences of substring `old` with `new`.""" |
---|
| 1425 | for i in range(len(self.data)): |
---|
| 1426 | self.data[i] = self.data[i].replace(old, new) |
---|
| 1427 | |
---|
| 1428 | |
---|
| 1429 | class StateMachineError(Exception): pass |
---|
| 1430 | class UnknownStateError(StateMachineError): pass |
---|
| 1431 | class DuplicateStateError(StateMachineError): pass |
---|
| 1432 | class UnknownTransitionError(StateMachineError): pass |
---|
| 1433 | class DuplicateTransitionError(StateMachineError): pass |
---|
| 1434 | class TransitionPatternNotFound(StateMachineError): pass |
---|
| 1435 | class TransitionMethodNotFound(StateMachineError): pass |
---|
| 1436 | class UnexpectedIndentationError(StateMachineError): pass |
---|
| 1437 | |
---|
| 1438 | |
---|
| 1439 | class TransitionCorrection(Exception): |
---|
| 1440 | |
---|
| 1441 | """ |
---|
| 1442 | Raise from within a transition method to switch to another transition. |
---|
| 1443 | |
---|
| 1444 | Raise with one argument, the new transition name. |
---|
| 1445 | """ |
---|
| 1446 | |
---|
| 1447 | |
---|
| 1448 | class StateCorrection(Exception): |
---|
| 1449 | |
---|
| 1450 | """ |
---|
| 1451 | Raise from within a transition method to switch to another state. |
---|
| 1452 | |
---|
| 1453 | Raise with one or two arguments: new state name, and an optional new |
---|
| 1454 | transition name. |
---|
| 1455 | """ |
---|
| 1456 | |
---|
| 1457 | |
---|
| 1458 | def string2lines(astring, tab_width=8, convert_whitespace=0, |
---|
| 1459 | whitespace=re.compile('[\v\f]')): |
---|
| 1460 | """ |
---|
| 1461 | Return a list of one-line strings with tabs expanded, no newlines, and |
---|
| 1462 | trailing whitespace stripped. |
---|
| 1463 | |
---|
| 1464 | Each tab is expanded with between 1 and `tab_width` spaces, so that the |
---|
| 1465 | next character's index becomes a multiple of `tab_width` (8 by default). |
---|
| 1466 | |
---|
| 1467 | Parameters: |
---|
| 1468 | |
---|
| 1469 | - `astring`: a multi-line string. |
---|
| 1470 | - `tab_width`: the number of columns between tab stops. |
---|
| 1471 | - `convert_whitespace`: convert form feeds and vertical tabs to spaces? |
---|
| 1472 | """ |
---|
| 1473 | if convert_whitespace: |
---|
| 1474 | astring = whitespace.sub(' ', astring) |
---|
| 1475 | return [s.expandtabs(tab_width).rstrip() for s in astring.splitlines()] |
---|
| 1476 | |
---|
| 1477 | def _exception_data(): |
---|
| 1478 | """ |
---|
| 1479 | Return exception information: |
---|
| 1480 | |
---|
| 1481 | - the exception's class name; |
---|
| 1482 | - the exception object; |
---|
| 1483 | - the name of the file containing the offending code; |
---|
| 1484 | - the line number of the offending code; |
---|
| 1485 | - the function name of the offending code. |
---|
| 1486 | """ |
---|
| 1487 | type, value, traceback = sys.exc_info() |
---|
| 1488 | while traceback.tb_next: |
---|
| 1489 | traceback = traceback.tb_next |
---|
| 1490 | code = traceback.tb_frame.f_code |
---|
| 1491 | return (type.__name__, value, code.co_filename, traceback.tb_lineno, |
---|
| 1492 | code.co_name) |
---|