`-o` option should overwrite output files by default

[GoogleCodeExporter]

The `-o` option should overwrite hte target output file by default, because 
that's the common case; removing the output before running the `simul.py` 
script is inconvenient and error-prone.

Original issue reported on code.google.com by tyanko.a...@gmail.com on 16 Feb 2012 at 4:49

[GoogleCodeExporter]

Original comment by riccardo.murri@gmail.com on 17 Feb 2012 at 9:01

• Added labels: Type-Enhancement
• Removed labels: Type-Defect

[GoogleCodeExporter]

As the output file is being used for writing the current state of the simulator 
on each iteration an "overwrite procedure" could be defined only during the 
initialization of the simulator: 

88         # Delete input file if such exists form previous simulation.  
89         if os.path.isfile(self.output_file):
90             os.remove(self.output_file)

Is there some other way of doing so? 

Original comment by tyanko.a...@gmail.com on 20 Feb 2012 at 1:30

• Changed state: Fixed

[GoogleCodeExporter]

| As the output file is being used for writing the current state of the
| simulator on each iteration an "overwrite procedure" could be defined only
| during the initialization of the simulator:
|
| 88         # Delete input file if such exists form previous simulation.
| 89         if os.path.isfile(self.output_file):
| 90             os.remove(self.output_file)
|
| Is there some other way of doing so?

Isn't it just a question of changing the "mode" part in the `open()`
call for the output file?

E.g., to append you do `output_file = open(..., 'a')`, to overwrite
you do: `output_file = open(..., 'w')`.

Original comment by riccardo.murri@gmail.com on 20 Feb 2012 at 2:02

[GoogleCodeExporter]

Yes, this way is also possible. Change the code to:
# Just open the file in write mode in order to overwrite previous one 
with open(self.output_file, 'w') as output:
    output.write("")
    output.closed

Original comment by tyanko.a...@gmail.com on 20 Feb 2012 at 2:46

[GoogleCodeExporter]

| Yes, this way is also possible. Change the code to:
| # Just open the file in write mode in order to overwrite previous one
| with open(self.output_file, 'w') as output:
|    output.write("")
|    output.closed

No :-)

1. The `with open(...)` statement in Python will *close* the file at
   exit of the following block.  So it's good for doing
   temporary/localized work on a file, but this is not the case  in
   `simul.py`: we need the output file open from the start to the end
   of the simulation work.

2. Similarly, the `with open(...)` in `before(...)` should be changed
   to just write to an output file that is opened in the ctor and
   saved as object attribute.

3. Finally, `output.closed` is not a method invocation! It's an
   attribute lookup, that will return whatever value the
   `output.closed` attribute has (or raise an exception if no such
   attribute exists).  Also, --see 1.-- the whole point of using
   `with` blocks is that you should not care about closing files on
   exit...

Original comment by riccardo.murri@gmail.com on 21 Feb 2012 at 12:21

[GoogleCodeExporter]

Changed like this:
in `__init__()`
75         self.output_file = open(output_file, 'w')
in `before()`
..
153         if len(self._running) == 0 and len(self._pending)....
154             log.info("No more jobs, stopping here")
155             self.output_file.close()
156             sys.exit(0)
157 
158         self.output_file.write(

Original comment by tyanko.a...@gmail.com on 21 Feb 2012 at 2:22