Source Code for Module lepl.matchers.variables

  1   
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  3  # (MPL) Version 1.1 (the "License"); you may not use this file except 
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  9  # the License for the specific language governing rights and 
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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  Display information when matchers that are bound to variables are called. 
 32   
 33  This is possible thanks to a neat trick suggested by Carl Banks on c.l.p  
 34  ''' 
 35   
 36  from __future__ import generators, print_function 
 37  from contextlib import contextmanager 
 38  from sys import stderr, _getframe 
 39   
 40  from lepl.stream.core import s_debug, s_line, s_kargs 
 41  from lepl.matchers.support import trampoline_matcher_factory 
 42  from lepl.support.lib import fmt, str 
 43   
 44   
 45  @trampoline_matcher_factory() 
 46 -def NamedResult(name, matcher, out=stderr): 
 47       
 48      def fmt_stream(stream): 
 49          try: 
 50              (line, _) = s_line(stream, False) 
 51              text = str(line) 
 52              if len(text) > 20: 
 53                  text = text[:17] + '...' 
 54              return repr(text) 
 55          except StopIteration: 
 56              return '<EOS>' 
 57       
 58      def record_success(count, stream_in, result): 
 59          (value, stream_out) = result 
 60          count_desc = fmt(' ({0})', count) if count > 1 else '' 
 61          # Python bug #4618 
 62          print(fmt('{0}{1} = {2}\n    {3} -> {4}',  
 63                       name, count_desc, value,  
 64                       fmt_stream(stream_in), fmt_stream(stream_out)),  
 65                file=out, end=str('\n')) 
 66           
 67      def record_failure(count, stream_in): 
 68          # Python bug #4618 
 69          print(fmt('! {0} (after {1} matches)\n    {2}', name, count,  
 70                       fmt_stream(stream_in)), 
 71                file=out, end=str('\n')) 
 72       
 73      def match(support, stream): 
 74          count = 0 
 75          generator = matcher._match(stream) 
 76          try: 
 77              while True: 
 78                  value = yield generator 
 79                  count += 1 
 80                  record_success(count, stream, value) 
 81                  yield value 
 82          except StopIteration: 
 83              record_failure(count, stream) 
 84   
 85      return match 
 86   
 87   
 88 -def _adjust(text, width, pad=False, left=False): 
 89      if len(text) > width: 
 90          text = text[:width-3] + '...' 
 91      if pad and len(text) < width: 
 92          space = ' ' * (width - len(text)) 
 93          if left: 
 94              text = space + text 
 95          else: 
 96              text = text + space 
 97      return text 
 98   
 99   
100 -def name(name, show_failures=True, width=80, out=stderr): 
101       
102      left = 3 * width // 5 - 1 
103      right = 2 * width // 5 - 1 
104       
105      def namer(stream_in, matcher): 
106          try: 
107              (result, stream_out) = matcher() 
108          except StopIteration: 
109              if show_failures: 
110                  stream = \ 
111                      _adjust(fmt('stream = {rest}', **s_kargs(stream_in)),  
112                              right)  
113                  str_name = _adjust(name, left // 4, True, True) 
114                  match = _adjust(fmt(' {0} failed', str_name), left, True) 
115                  # Python bug #4618 
116                  print(match + ' ' + stream, file=out, end=str('\n')) 
117              raise StopIteration 
118          else: 
119              try: 
120                  try: 
121                      rest = fmt('{rest}', **s_kargs(stream_out)) 
122                  except StopIteration: 
123                      rest = '<EOS>' 
124                  stream = _adjust(fmt('stream = {0}', rest), right)  
125                  str_name = _adjust(name, left // 4, True, True) 
126                  match = _adjust(fmt(' {0} = {1}', str_name, result), left, True) 
127                  # Python bug #4618 
128                  print(match + ' ' + stream, file=out, end=str('\n')) 
129                  return (result, stream_out) 
130              except Exception as e: 
131                  print('Error in trace', file=out, end=str('\n')) 
132                  print(repr(e), file=out, end=str('\n')) 
133                  return (result, stream_out) 
134                   
135      return namer 
136   
137   
138  @contextmanager 
139 -def TraceVariables(on=True, show_failures=True, width=80, out=stderr): 
140      ''' 
141      Add this as a context (`with TraceVariables():`) and you will see  
142      debug logging indicating how variables are bound during matching. 
143      ''' 
144      if on: 
145          before = _getframe(2).f_locals.copy() 
146      yield None 
147      if on: 
148          after = _getframe(2).f_locals 
149          for key in after: 
150              value = after[key] 
151              if key not in before or value != before[key]: 
152                  try: 
153                      try: 
154                          value.wrapper.append(name(key, show_failures, width, out)) 
155                      except AttributeError: 
156                          value.trace_variables = name(key, show_failures, width, out) 
157                  except: # what exception? 
158                      print('Unfortunately the following matchers cannot ' 
159                            'be tracked:', end=str('\n')) 
160                      print(fmt('  {0} = {1}', key, value), end=str('\n')) 
161