Source Code for Module lepl.lexer.lines.monitor

 1   
 2  # The contents of this file are subject to the Mozilla Public License 
 3  # (MPL) Version 1.1 (the "License"); you may not use this file except 
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11  # 
12  # The Original Code is LEPL (http://www.acooke.org/lepl) 
13  # The Initial Developer of the Original Code is Andrew Cooke. 
14  # Portions created by the Initial Developer are Copyright (C) 2009-2010 
15  # Andrew Cooke (andrew@acooke.org). All Rights Reserved. 
16  # 
17  # Alternatively, the contents of this file may be used under the terms 
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20  # of the LGPL License are applicable instead of those above. 
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29   
30  ''' 
31  Support the stack-scoped tracking of indent level blocks. 
32  ''' 
33   
34   
35  from lepl.core.monitor import ActiveMonitor 
36  from lepl.support.state import State 
37  from lepl.support.lib import LogMixin, fmt 
38   
39   
40 -class BlockMonitor(ActiveMonitor, LogMixin): 
41      ''' 
42      This tracks the current indent level (in number of spaces).  It is 
43      read by `Line` and updated by `Block`. 
44      ''' 
45       
46 -    def __init__(self, start=0): 
47          ''' 
48          start is the initial indent (in spaces). 
49          ''' 
50          super(BlockMonitor, self).__init__() 
51          self.__stack = [start] 
52          self.__state = State.singleton() 
53           
54 -    def push_level(self, level): 
55          ''' 
56          Add a new indent level. 
57          ''' 
58          self.__stack.append(level) 
59          self.__state[BlockMonitor] = level 
60          self._debug(fmt('Indent -> {0:d}', level)) 
61           
62 -    def pop_level(self): 
63          ''' 
64          Drop one level. 
65          ''' 
66          self.__stack.pop() 
67          if not self.__stack: 
68              raise OffsideError('Closed an unopened indent.')  
69          self.__state[BlockMonitor] = self.indent 
70          self._debug(fmt('Indent <- {0:d}', self.indent)) 
71          
72      @property 
73 -    def indent(self): 
74          ''' 
75          The current indent value (number of spaces). 
76          ''' 
77          return self.__stack[-1] 
78       
79   
80 -def block_monitor(start=0): 
81      ''' 
82      Add an extra lambda for the standard monitor interface. 
83      ''' 
84      return lambda: BlockMonitor(start) 
85   
86   
87 -class OffsideError(Exception): 
88      ''' 
89      The exception raised by problems when parsing whitespace significant 
90      code. 
91      ''' 
92