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comparison ply-3.8/ply/ygen.py @ 7267:343ff337a19b

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<ais523> ` tar -xf ply-3.8.tar.gz
author HackBot
date Wed, 23 Mar 2016 02:40:16 +0000
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7266:61a39a120dee 7267:343ff337a19b
1 # ply: ygen.py
2 #
3 # This is a support program that auto-generates different versions of the YACC parsing
4 # function with different features removed for the purposes of performance.
5 #
6 # Users should edit the method LParser.parsedebug() in yacc.py. The source code
7 # for that method is then used to create the other methods. See the comments in
8 # yacc.py for further details.
9
10 import os.path
11 import shutil
12
13 def get_source_range(lines, tag):
14 srclines = enumerate(lines)
15 start_tag = '#--! %s-start' % tag
16 end_tag = '#--! %s-end' % tag
17
18 for start_index, line in srclines:
19 if line.strip().startswith(start_tag):
20 break
21
22 for end_index, line in srclines:
23 if line.strip().endswith(end_tag):
24 break
25
26 return (start_index + 1, end_index)
27
28 def filter_section(lines, tag):
29 filtered_lines = []
30 include = True
31 tag_text = '#--! %s' % tag
32 for line in lines:
33 if line.strip().startswith(tag_text):
34 include = not include
35 elif include:
36 filtered_lines.append(line)
37 return filtered_lines
38
39 def main():
40 dirname = os.path.dirname(__file__)
41 shutil.copy2(os.path.join(dirname, 'yacc.py'), os.path.join(dirname, 'yacc.py.bak'))
42 with open(os.path.join(dirname, 'yacc.py'), 'r') as f:
43 lines = f.readlines()
44
45 parse_start, parse_end = get_source_range(lines, 'parsedebug')
46 parseopt_start, parseopt_end = get_source_range(lines, 'parseopt')
47 parseopt_notrack_start, parseopt_notrack_end = get_source_range(lines, 'parseopt-notrack')
48
49 # Get the original source
50 orig_lines = lines[parse_start:parse_end]
51
52 # Filter the DEBUG sections out
53 parseopt_lines = filter_section(orig_lines, 'DEBUG')
54
55 # Filter the TRACKING sections out
56 parseopt_notrack_lines = filter_section(parseopt_lines, 'TRACKING')
57
58 # Replace the parser source sections with updated versions
59 lines[parseopt_notrack_start:parseopt_notrack_end] = parseopt_notrack_lines
60 lines[parseopt_start:parseopt_end] = parseopt_lines
61
62 lines = [line.rstrip()+'\n' for line in lines]
63 with open(os.path.join(dirname, 'yacc.py'), 'w') as f:
64 f.writelines(lines)
65
66 print('Updated yacc.py')
67
68 if __name__ == '__main__':
69 main()
70
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74