Source Code for Module jazzparser.utils.input

 1  """Utilities for chord input processing 
 2   
 3  Various general utilities for processing input to the parser. These are  
 4  for processing string chord input and date back to the days when all the  
 5  parser's input was in that form. 
 6   
 7  DbInput: this class has moved to L{jazzparser.data.input}, where it fits into  
 8  a more general framework of input processing. 
 9   
10  """ 
11  """ 
12  ============================== License ======================================== 
13   Copyright (C) 2008, 2010-12 University of Edinburgh, Mark Granroth-Wilding 
14    
15   This file is part of The Jazz Parser. 
16    
17   The Jazz Parser is free software: you can redistribute it and/or modify 
18   it under the terms of the GNU General Public License as published by 
19   the Free Software Foundation, either version 3 of the License, or 
20   (at your option) any later version. 
21    
22   The Jazz Parser is distributed in the hope that it will be useful, 
23   but WITHOUT ANY WARRANTY; without even the implied warranty of 
24   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
25   GNU General Public License for more details. 
26    
27   You should have received a copy of the GNU General Public License 
28   along with The Jazz Parser.  If not, see <http://www.gnu.org/licenses/>. 
29   
30  ============================ End license ====================================== 
31   
32  """ 
33  __author__ = "Mark Granroth-Wilding <mark.granroth-wilding@ed.ac.uk>"  
34   
35 -def assign_durations(string): 
36      """ 
37      Computes the durations for each chord token in the string. 
38      Chords on their own get a duration of 1. Comma-separated sequences 
39      of chords get a duration of 1, split evenly between the members 
40      of the sequence. 
41       
42      """ 
43      from jazzparser.data import Fraction 
44      # Make sure the commas are separate tokens 
45      string = string.replace(",", " , ") 
46      string = string.replace(":", " : ") 
47      string = string.replace("|", "") 
48      tokens = string.split() 
49      # Group tokens into comma-separated sequences 
50      in_sequence = False 
51      units = [] 
52      for token in tokens: 
53          if token == "," or token == ":": 
54              # The next token is in the same sequence as the last 
55              in_sequence = True 
56          elif in_sequence: 
57              # This token should be added to the previous token's sequence 
58              units[-1].append(token) 
59              in_sequence = False 
60          else: 
61              # Start of a new sequence 
62              units.append([token]) 
63               
64      # Now build the list of durations 
65      durations = [] 
66      for unit in units: 
67          # Each sequence has a total length of 4 (assume 4 beats in bar) 
68          # Split this between its members. 
69          denominator = len(unit) 
70          members = [Fraction(4,denominator)] * denominator 
71          durations.extend(members) 
72       
73      return durations 
74   
75 -def strip_input(string): 
76      """ 
77      Pre-processes the input string, removing any allowed meaningless  
78      characters, and returns the resulting string. 
79      """ 
80      from jazzparser import settings 
81      for ignored in settings.IGNORED_INPUT_STRINGS + [":",","]: 
82          string = string.replace(ignored," ") 
83      return string 
84