On 03/09/2013 11:56 AM, Kene Meniru wrote:
Dave Angel wrote:
On 03/09/2013 10:34 AM, Kene Meniru wrote:
To use my program the user needs a script file I will call user.py.
Functions from my program must be imported into this file with
something like "from myapp import *".
And does the user run this script by doing
python user.py
Yes
myapp.py is a module in my program that has all the functions that the
user needs to describe building components. There is also a main
controller object that is imported into myapp.py module called app.
When python parses user.py module,
You presumably mean, "When Python runs the script user.py"
When the user types and enters at the command line: "python user.py"
the functions the user has provided
creates building components which are then saved in a dictionary
located in an object called doc that is part of my program.
What program is that? Looks to me like you're writing a series of
modules, a framework perhaps, that is invoked by the user script.
Yes. I am writing many functions and classes in many modules that work
together.
The user is free to use the functions in myapp.py to describe building
components. When this process is complete or when the user wants to
view their work-in-progress, they have to place a function called
view() on the last line in user.py.
Don't you mean the code in user.py has to *call* the function app.view()
when they're all done with defining the components? That has nothing to
do with being the last line.
Well... yes. The function is app.view() but it is not called automatically
by the code in user.py. The following is an example of the contents of
user.py
################### begin user.py #############################
from buildes import *
site("Willow_Creek_Ct", 5)
"""Create a site with name and number of boundaries."""
level("level1", 3000)
level("level2", 3000)
"""Create levels with name and height."""
setLevel("level1")
"""Set the current level to place objects"""
space("Dining", 5)
"""Create a space with 5 sides (walls)"""
linearSide("Dining-S1", 3683, 152, 0)
"""Initialize the first side of space called Dining"""
offset("Dining-S1", (3000, 0, 0))
"""Install the first side of Dining space called Dining-S1"""
view(POV)
"""Exports objects to POV-Ray format"""
################### end user.py #############################
This function currently exports
You mean writes files into the file system?
Yes.
the components into POV-Ray or OpenSCAD format. These are CAD programs
that read script files to render or create images of the described
artifacts. So this means that to view their work the user needs to run
python on user.py to export the building and then run POV-Ray or
OpenSCAD on the exported file to see the building.
At that point, the user.py script has completed, and Python is done,
right?
Yes
I want to make it possible for the user to preview the building
components without having to use the external rendering programs. I
can currently have the app object provide this preview but it means
that the user will have to process user.py with python then exit the
graphic window each time they need to see changes.
What changes are those? You can't change a script while it's executing.
Could you clarify this so I can rethink the following paragraph?
Working on the user.py is an iterative process. The user adds new objects or
changes the parameters of the objects already there and envokes "python
user.py" each time to see the changes made. Just like using a program like
LaTeX. You edit your text file and run LaTeX on the file to see the changes
you made. The process continues until you finish the document.
So the solution I am looking for is to have a graphic window open that
watches user.py for changes.
It would then have to be a separate executable. Are you really saying
you want this window to keep "running" after the script ends? And that
somehow it notices that the user has rerun the user.py script? Or
could it simply be a window created during the user.py run that stays
running till it's closed, which ends the script as well?
If there is a change the graphic window
updates the rendition of the created components without further
intervention by the user.
Is running the script considered intervention? Or do you mean literally
that somebody watches the script for changes (eg. by watching the
timestamp)?
However this means that the graphic must
somehow run python to parse user.py and then be able to access the
objects stored in doc so that the coordinates can be used to update
the view. This is where I am having difficulty.
Either the "graphic" is in the same process, in which case the script
can only be "parsed" once, or the "graphic" is in a second process, in
which case you're talking some interesting interprocess communication
(ipc). That's certainly do-able, but it's way beyond the scope of the
kind of programming you've been talking about. But sometimes just using
a regular file for transfer is adequate.
If you really want two processes, then you should consider having the
user run the the graphic app, with a commandline parameter of user.py,
and have it create the user.py process. The user.py process runs till
it has created all the data, then sends it via some ipc to the graphic
app. Once sent, it terminates. The graphic app reads the ipc stuff,
updates its graphics, then idles, watching for timestamp changes on the
user.py file.
If you choose to use external file(s) to communicate between the two
processes, you might use pickle or shelve.
--
DaveA
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