Configuration files (Python version)

This version is to be completed. Refer to the Scheme version and code in example dueca_cnf.py and dueca_mod.py instead.

Setting parameters

The Python and Scheme script interfaces share the mechanism with ParameterTable tables for defining parameters and calls that can be used to define a module (or another script-created object, such as DUECA's core objects, or a ScriptCreatable). In a Python script, you first create the module object, and then use the .param call to add parameters, and finally add the module object to a list that will be passed to the Entity. These .param calls can also be chained, like:

mymods.append(dueca.Module(
    "mymodule", "", sim_priority).param(    # set of keyword-value pairs
        add_view = "view1",
        view_fov = 40,
        view_orientation = 0).param(        # next set of keyword-value
        add_view = "view2",
        view_fov = 45,
        view_orientation = -55))

You see here that the "keyword = value" method of specifying data is used. Scheme keywords allow the use of hyphens ('-') in your code, and consequently there are still a lot of ParameterTables with hyphens in there. To make the transition to Python easier, these hyphens are all silently translated to underscores for the names of the Python keywords.

Note that you cannot combine everything into one .param call here, since the Python syntax won't allow repeated keywords.

In addition, the now obsolete Python 2.7 did NOT preserve the order of parameters in a named parameter list. In the above example, if "add_view" somehow creates a new view structure, which you thereafter want to modify with view_fov, etc., there will be no guarantee that add_view arrives first at your module class. In that case you need to apply only a single keyword per .param call, like:

mymods.append(dueca.Module(
    "mymodule", "", sim_priority).param(    # set of keyword-value pairs
        add_view = "view1").param(          # close off, and next set
        view_fov = 40).param(               # etc., etc.
        view_orientation = 0).param(       
        add_view = "view2").param(
        view_fov = 45).param(
        view_orientation = -55))

As an alternative to the keyword-value settings, you can also supply tuples, with the first element of the tuple being a string with the keyword, and the second element being the new value:

mymods.append(dueca.Module(
    "mymodule", "", sim_priority).param( # keyword-value pairs in tuples
        ("add_view", "view1"),
        ("view_fov", 40),
        ("view_orientation", 0),
        ("add_view", "view2"),           # for the next set, simply continue
        ("view_fov", 45),
        ("view_orientation", -55)
    ) # end param call
   ) # end append