Import and classes confusion - function

If I have a file called init.py:
class main:
import foo
import bar
and another file called foo.py, how can I import init's "main" class? Because I've seen this working instead of classes with functions, and it is a bit confusing, how classes and functions rank.
e.g.: if i import bar, what I am importing, the class or the file? if I want to import the class? and what about calling a function inside the class?

In the case:
# foo.py
import string
class Bar(object):
...
def baz(...):
...
You have two choices:
Using import foo would bring foo into your namespace, giving access to foo.Bar and foo.baz; or
You could e.g. from foo import baz to bring baz directly into the namespace, so you can access it without needing foo..
Note that you can have both classes and functions at the top level, which is also where imports should be done.

Suppose you have a file called Foo.py, and inside that file you defined a class called Foo, like this.
class Foo:
def __init__(self, args):
# perform initialization
Now you want to use this class in a different file called main.py, which we will assume for simplicity is in the same directory. You have two options.
The first option is to use import Foo, and then refer to the class by Foo.Foo.
import Foo
myFoo = Foo.Foo(args)
The second option is to write from Foo import Foo, and refer to the class by Foo.
from Foo import Foo
myFoo = Foo(args)

Related

how to override/extend chisel signal naming

It seems not an easy thing to do or even impossible, but we are using a naming convention that prefix or postfix signals with "i_" or "o_" for inputs/outputs in verilog.
Is there some method to mess with or override inside the chisel library to to that?
I saw that except for clock and reset, all signals have "io" prefix.
Is is possible to use just "i" for input and "o" for output?
The easiest way to do this is to probably use a MultiIOModule. However, you can also do it with suggestName. Both approaches are shown below.
MultiIOModule
This a more flexible Module that lets you call the IO method to add ports to a module more than once. (Module requires that you define an io member and only allows you to call IO once.)
Because MultiIOModule frees you from the constraints of val io = ... you can use the prefix/postfix naming that you want with the names of your vals. Reflective naming will then get these right in the generated Verilog.
Consider the following Chisel code:
import chisel3._
import chisel3.stage.{ChiselStage, ChiselGeneratorAnnotation}
class Foo extends MultiIOModule {
val i_bar = IO(Input(Bool()))
val o_baz = IO(Output(Bool()))
o_baz := ~i_bar
}
(new ChiselStage).execute(Array.empty, Seq(ChiselGeneratorAnnotation(() => new Foo)))
This produces the following Verilog:
module Foo(
input clock,
input reset,
input i_bar,
output o_baz
);
assign o_baz = ~ i_bar;
endmodule
SuggestName
As an alternative, you can use the suggestName method to change the name to be different from what reflective naming (getting the name from the name of the val) would use.
Using suggestName you can coerce the names to be whatever you want. The following Chisel produces the same Verilog as above:
class Foo extends MultiIOModule {
val a = IO(Input(Bool())).suggestName("i_bar")
val b = IO(Output(Bool())).suggestName("o_baz")
b := ~a
}

How to keep val names under withClock() or withClockAndReset() scopes

Val names under withClock() & withClockAndReset() scopes tend to lose their coded names in the generated Verilog file.
So far in order to maintain to original names I used suggestName() function to force the original name.
However I wonder if there is a smarter way do it ? is there a way to force all vals to keep their names without adding suggestName() to each val declaration ?
As Kamyar mentioned in his comment, you should use the #chiselName macro
import chisel3._
import chisel3.experimental.chiselName
#chiselName
class MyModule extends Module {
...
withClock(otherClock) {
val importantReg = Reg(...) // <- this will now get a name
}
}
The way #chiselName works is it will automatically add a .suggestName to each val.

No instance of play.api.libs.json.Format is available for scala.Iterable[java.lang.String]

Trying to map a simple class using play version 2.6.2 and scala 2.11.11
import play.api.libs.json._
import play.api.libs.json.util._
import play.api.libs.json.Reads._
import play.api.libs.json.Writes._
import play.api.libs.json.Format._
import play.api.libs.functional.syntax._
case class ObjectInfo (
names : Iterable[String],
info : Iterable[String]
)
object ObjectInfo {
/**
* Mapping to and from JSON.
*/
implicit val documentFormatter = Json.format[ObjectInfo]
}
getting:
No instance of play.api.libs.json.Format is available for
scala.Iterable[java.lang.String], scala.Iterable[java.lang.String] in
the implicit scope (Hint: if declared in the same file, make sure it's
declared before)
I was expecting Play to automatically map these fields since they're not complex object types but simple Collection of strings.
You provide "too much" implicit stuff with your imports. If you remove all imports but the first one, it will compile and do what you want.
If you enable implicit parameter logging via the scalac option -Xlog-implicits, you will see various "ambigouity" and "diverging implicit expansion" errors. The conflicting imports are import play.api.libs.json.Reads._/import play.api.libs.json.Writes._ and import play.api.libs.json.Format._. Maybe someone else can explain this conflict in more detail.

Call up a function from another module

I am making a project where I need several modules which are imported into one main module. I have decided to move the interaction to a single Tkinter window. Instead of using input() I use tkinter.Entry(), for example. I have functions for each step of the interaction.
When I get past the last function of the first module, the configured button has a command to go to a function in the second module. I get an error saying that the command is not defined.
I seem unable to import the configured button variable into the next module, and anything else I tried gave no result. It simply doesn't go to the next module after the first module is done.
I have made the main Tkinter window in the main module and have it that it will mainloop after importing the other modules. Shouldn't the function I want to call upon be defined? How can I get from one function to the next if the latter is in a separate module?
Here is a minimal example:
main_script.py
import tkinter
mainwindow = tkinter.Tk()
# here i set the window to a certain size etc.
import mod1
import mod2
mainwindow.mainloop()
mod1.py
import tkinter
def button1():
label.destroy()
button1.destroy()
button2.config(text = "continue", command = func2)
def button2():
label.destroy()
button1.destroy()
button2.config(text = "continue", command = func2)
label = tkinter.Label(text = "example label")
button1 = tkinter.Button(text = "button1", command = button1)
button2 = tkinter.Button(text = "button2", command = button2)
label.pack()
button1.pack()
button2.pack()
mod2.py
def func2():
button2.destroy()
print ("haha it works...")
Importing a module has no effect on what the module you import can see. If you want to use mod1 contents in mod2 and mod2 contents in mod1, you need to have them import each other and refer to each other's contents with the appropriate module:
# mod1
import mod2
...
button2.config(text = "continue", command = mod2.func2)
# mod2
import mod1
def func2():
mod1.button2.destroy()
Circular imports cause nasty initialization order issues, though, so imports like this are a bad idea. When dividing your code into modules, try to do so in such a way that import loops like this aren't necessary.

Jython classes and variable scope

What I want to know is, how can I create GUI elements using swing inside a Jython class so that they can be referenced from outside the class, and I can use statements like button.setText("Hello") on an object that was created inside another class. For example:
foo.py:
from javax.swing import *
class Test():
def __init__(self):
frame = JFrame("TEST")
button = JButton("Hey")
frame.add(button)
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)
frame.setSize(300,200)
frame.show()
and then I have another file called somethingelse.py:
from foo import *
run = Test()
If I were to want to change the button text by using run.button.setText("Message"), how could I organise the Test() class such that I could change the text from the second file, somethingelse.py.
Your code is throwing away the references it has to the controls, so you can't access them from anywhere - frame and button are local variables, and disappear once __init__ returns.
You should (minimally) make them object members:
class Test():
def __init__(self):
self.frame = JFrame("TEST")
self.button = JButton("Hey")
self.frame.add(button)
# ...
You can then say:
from foo import *
run = Test()
run.button.setText("Message")