Source Code for Module lepl.stream.factory

  1   
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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 
 18  # of the LGPL license (the GNU Lesser General Public License, 
 19  # http://www.gnu.org/licenses/lgpl.html), in which case the provisions 
 20  # of the LGPL License are applicable instead of those above. 
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 23  # terms of the LGPL License and not to allow others to use your version 
 24  # of this file under the MPL, indicate your decision by deleting the 
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 26  # required by the LGPL License.  If you do not delete the provisions 
 27  # above, a recipient may use your version of this file under either the 
 28  # MPL or the LGPL License. 
 29   
 30   
 31  from collections import Iterable 
 32   
 33  from lepl.stream.simple import SequenceHelper, StringHelper, ListHelper 
 34  from lepl.stream.iter import IterableHelper, Cons 
 35  from lepl.support.lib import basestring, fmt, add_defaults, file 
 36  from lepl.lexer.stream import TokenHelper 
 37   
 38   
 39 -class StreamFactory(object): 
 40      ''' 
 41      Given a value (typically a sequence), generate a stream. 
 42      ''' 
 43       
 44 -    def from_string(self, text, **kargs): 
 45          ''' 
 46          Provide a stream for the contents of the string. 
 47          ''' 
 48          add_defaults(kargs, {'factory': self}) 
 49          return (0, StringHelper(text, **kargs)) 
 50   
 51 -    def from_list(self, list_, **kargs): 
 52          ''' 
 53          Provide a stream for the contents of the list. 
 54          ''' 
 55          add_defaults(kargs, {'factory': self}) 
 56          return (0, ListHelper(list_, **kargs)) 
 57   
 58 -    def from_sequence(self, sequence, **kargs): 
 59          ''' 
 60          Return a generic stream for any indexable sequence. 
 61          ''' 
 62          add_defaults(kargs, {'factory': self}) 
 63          return (0, SequenceHelper(sequence, **kargs)) 
 64   
 65 -    def from_iterable(self, iterable, **kargs): 
 66          ''' 
 67          Provide a stream for the contents of the iterable.  This assumes that 
 68          each value from the iterable is a "line" which will, in turn, be 
 69          passed to the stream factory. 
 70          ''' 
 71          add_defaults(kargs, {'factory': self}) 
 72          cons = Cons(iterable) 
 73          return ((cons, self(cons.head, **kargs)), IterableHelper(**kargs)) 
 74       
 75 -    def from_file(self, file_, **kargs): 
 76          ''' 
 77          Provide a stream for the contents of the file.  There is no  
 78          corresponding `from_path` because the opening and closing of the 
 79          path must be done outside the parsing (or the contents will become 
 80          unavailable), so use instead: 
 81            with open(path) as f: 
 82                parser.parse_file(f) 
 83          which will close the file after parsing. 
 84          ''' 
 85          try: 
 86              gkargs = kargs.get('global_kargs', {}) 
 87              add_defaults(gkargs, {'filename': file_.name}) 
 88              add_defaults(kargs, {'global_kargs': gkargs}) 
 89          except AttributeError: 
 90              pass 
 91          return self.from_iterable(file_, **kargs) 
 92       
 93 -    def to_token(self, iterable, **kargs): 
 94          ''' 
 95          Create a stream for tokens.  The `iterable` is a source of 
 96          (token_ids, sub_stream) tuples, where `sub_stream` will be 
 97          matched within the token. 
 98          ''' 
 99          return (Cons(iterable), TokenHelper(**kargs)) 
100               
101 -    def __call__(self, sequence, **kargs): 
102          ''' 
103          Auto-detect type and wrap appropriately. 
104          ''' 
105          if isinstance(sequence, basestring): 
106              return self.from_string(sequence, **kargs) 
107          elif isinstance(sequence, list): 
108              return self.from_list(sequence, **kargs) 
109          elif isinstance(sequence, file): 
110              return self.from_file(sequence, **kargs) 
111          elif hasattr(sequence, '__getitem__') and hasattr(sequence, '__len__'): 
112              return self.from_sequence(sequence, **kargs) 
113          elif isinstance(sequence, Iterable): 
114              return self.from_iterable(sequence, **kargs) 
115          else: 
116              raise TypeError(fmt('Cannot generate a stream for type {0}', 
117                                     type(sequence))) 
118   
119  DEFAULT_STREAM_FACTORY = StreamFactory() 
120