[GRASS-dev] [GRASS GIS] #2441: Underscore to avoid Python keywords used improperly in grass.script

GRASS GIS trac at osgeo.org
Fri Oct 3 15:11:58 PDT 2014

#2441: Underscore to avoid Python keywords used improperly in grass.script
 Reporter:  wenzeslaus                     |       Owner:  grass-dev@…              
     Type:  defect                         |      Status:  new                      
 Priority:  normal                         |   Milestone:  7.0.0                    
Component:  Default                        |     Version:  svn-trunk                
 Keywords:  PEP8, python keywords, parser  |    Platform:  Unspecified              
      Cpu:  Unspecified                    |  
 When a module parameter is the same as one of Python keywords, we are
 adding and underscore before the name of parameter, so call of a module:

 run_command('s.module', lambda="abc")


 run_command('s.module', _lambda="abc")

 But this is wrong, according to
 [http://legacy.python.org/dev/peps/pep-0008/ PEP8] and commonly used
 standard, prefixed underscore means private. To avoid conflicts you should
 use underscore at the end:

 _single_leading_underscore: weak "internal use" indicator. E.g. from M
 import * does not import objects whose name starts with an underscore.

 single_trailing_underscore_: used by convention to avoid conflicts with
 Python keyword, e.g.

 Tkinter.Toplevel(master, class_='ClassName')

 If there are no objections I will commit the change soon hopefully with
 tests and documentation (in case it is not already documented). Please
 object now.

 I plan to commit in backwards compatible manner, so the old syntax will
 work (for some time).

 The code which will change is in grass.script.core and will look like

             if opt.startswith('_'):
                 opt = opt[1:]
             elif opt.endswith('_'):
                 opt = opt[:-1]

 or this:

             if opt.endswith('_'):
                 opt = opt[:-1]

 This should go to 7.0 to allow usage of the good way.

Ticket URL: <http://trac.osgeo.org/grass/ticket/2441>
GRASS GIS <http://grass.osgeo.org>

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