Making a calculator using Enthought's TraitsUI package

I used the traits and traitsUI packages of Enthought to write this calculator app. As you can see, I adapted it from another code I wrote that was in turn adapted from the TableEditor example code from the traitsUI examples.

Let me briefly explain what is going on in the code.

Button() creates, well, a button, which can then be linked to an action. the _*_button_fired() methods in the Application class are activated when the button is pressed and which do the necessary computation in the background! Similarly @on_trait_change() decorator also does a similar job. The method/function being decorated by such a decorator will be triggered/called when the attribute in the parenthesis changes! Traits takes care of listening to the attributes in the background, making life a lot easier for you!

Coming to how the calculator looks, that is defined in the View. Buttons or Items in general can be organized using the HGroup and VGroup methods, as done with the button layout. The calculated values are shown using a TextEditor object, which we borrowed from traitsUI, and we set it in a readonly mode. Maybe I should change this to let the user type the numbers instead of having to click the relevant buttons!

I guess that's all for now! I don't know if I did a good job at explaining this. If I'm missing anything out or not doing a good job, do point it out to me and I'd be glad to elaborate and do better! And yeah, this code was prettified and highlighted using this awesome website!

As always, any and every comment is appreciated!


#  Copyright (c) 2007, Enthought, Inc.
#  License: BSD Style.

"""
Implementation of a TableEditor demo plugin for Traits UI demo program

This demo shows the full behavior of a straightforward TableEditor.  Only
one style of TableEditor is implemented, so that is the one shown.
"""

# Import statements:

from traits.api \
    import HasTraits, HasStrictTraits, Instance, Int, Str, Button, Float, List, on_trait_change, File, Array

from traitsui.api \
    import View, Group, VGroup, HGroup, Item, TableEditor, TextEditor, ArrayEditor

# The class to be edited with the TableEditor:
class Application ( HasStrictTraits ):
    compute_box = Float(0.0) 
    temp = Float(0.0)
    count = Int(0)
    dot = Int(-1)

    nine_button = Button('9')
    eight_button = Button('8')
    seven_button = Button('7')
    six_button = Button('6')
    five_button = Button('5')
    four_button = Button('4')
    three_button = Button('3')
    two_button = Button('2')
    one_button = Button('1')

    equals_button = Button('=')
    add_button = Button('+')
    subtract_button = Button('-')
    mul_button = Button('*')
    div_button = Button('/')
    zero_button = Button('0')
    dot_button = Button('.')

    clr_button = Button('clr')

    def _nine_button_fired(self):
        if self.dot == -1:
            self.compute_box = self.compute_box*10 +9.0
        else:
            self.compute_box = (self.compute_box*10**(self.dot) +9.0)/10**(self.dot)
            self.dot +=1

    def _eight_button_fired(self):
        if self.dot == -1:
            self.compute_box = self.compute_box*10 +8.0
        else:
            self.compute_box = (self.compute_box*10**(self.dot) +8.0)/10**(self.dot)
            self.dot +=1

    def _seven_button_fired(self):
        if self.dot == -1:
            self.compute_box = self.compute_box*10 +7.0
        else:
            self.compute_box = (self.compute_box*10**(self.dot) +7.0)/10**(self.dot)
            self.dot +=1

    def _six_button_fired(self):
        if self.dot == -1: 
            self.compute_box = self.compute_box*10 +6.0
        else:
            self.compute_box = (self.compute_box*10**(self.dot) +6.0)/10**(self.dot)
            self.dot +=1

    def _five_button_fired(self):
        if self.dot == -1: 
            self.compute_box = self.compute_box*10 +5.0
        else:
            self.compute_box = (self.compute_box*10**(self.dot) +5.0)/10**(self.dot)
            self.dot +=1

    def _four_button_fired(self):
        if self.dot == -1: 
            self.compute_box = self.compute_box*10 +4.0
        else:
            self.compute_box = (self.compute_box*10**(self.dot) +4.0)/10**(self.dot)
            self.dot +=1

    def _three_button_fired(self):
        if self.dot == -1: 
            self.compute_box = self.compute_box*10 +3.0
        else:
            self.compute_box = (self.compute_box*10**(self.dot) +3.0)/10**(self.dot)
            self.dot +=1

    def _two_button_fired(self):
        if self.dot == -1: 
            self.compute_box = self.compute_box*10 +2.0
        else:
            self.compute_box = (self.compute_box*10**(self.dot) +2.0)/10**(self.dot)
            self.dot +=1

    def _one_button_fired(self):
        if self.dot == -1: 
            self.compute_box = self.compute_box*10 +1.0
        else:
            self.compute_box = (self.compute_box*10**(self.dot) +1.0)/10**(self.dot)
            self.dot +=1

    def _zero_button_fired(self):
        # does some weird shit!
        if self.dot == -1: 
            self.compute_box = self.compute_box*10
#        else:
            # dunno what to do when we want to add 
            # after zero!

    def _dot_button_fired(self):
            self.dot = 1

    @on_trait_change('equals_button')
    def eval_expr(self):
        if self.count == 1:
            self.compute_box += self.temp
        elif self.count == -1:
            self.compute_box -= self.temp
        elif self.count == 2:
            self.compute_box = self.compute_box*self.temp
        elif self.count == -2:
            self.compute_box = self.temp/self.compute_box

    def _add_button_fired(self):
        self.temp = self.compute_box
        self.compute_box = 0.0
        self.count = 1
        self.dot = -1

    def _subtract_button_fired(self):
        self.temp = self.compute_box
        self.compute_box = 0.0
        self.count = -1
        self.dot = -1

    def _mul_button_fired(self):
        self.temp = self.compute_box
        self.compute_box = 0.0
        self.count = 2
        self.dot = -1

    def _div_button_fired(self):
        self.temp = self.compute_box
        self.compute_box = 0.0
        self.count = -2
        self.dot = -1

    def _clr_button_fired(self):
        self.temp = 0.0
        self.compute_box = 0.0
        self.count = 0
        self.dot =-1 

    traits_view = View(
                    VGroup(
                        HGroup(Item('compute_box', label=" ", 
                               editor=TextEditor()),
                               Item('temp', label=" ",
                               editor=TextEditor(),
                               style="readonly")
                               ),
                        HGroup(
                            Group(
                                HGroup(Item('nine_button', label=" "), 
                                       Item('eight_button', label=" "),
                                       Item('seven_button', label=" "),
                                ),
                                HGroup(Item('six_button', label=" "), 
                                       Item('five_button', label=" "),
                                       Item('four_button', label=" "),
                                ),
                                HGroup(Item('three_button', label=" "), 
                                       Item('two_button', label=" "),
                                       Item('one_button', label=" "),
                                )
                            ),
                            VGroup(Item('zero_button', label=" "),
                                   Item('clr_button', label=" "),
                            ),
                            ),
                        HGroup(Item('mul_button', label=" "), 
                               Item('dot_button', label=" "),
                               Item('div_button', label=" "),
                               ),
                        HGroup(Item('add_button', label=" "), 
                               Item('equals_button', label=" "),
                               Item('subtract_button', label=" "),
                               )
                    ),
                    resizable = True,
                    buttons   = [ 'OK' ],
                    kind      = 'live',
                )

# Create the demo:
demo = Application()

# Run the demo (if invoked from the command line):
if __name__ == '__main__':
    demo.configure_traits()


Popular posts from this blog

Arxiv author affiliations using Python

So, I wanted to get author affiliation information from papers on arXiv. arXiv provides with an API to bulk query their database and get information. Following that, I look for the attribute 'arxiv:affiliation' in the html data. Here's the code - import urllib from BeautifulSoup import BeautifulStoneSoup   url = 'http://export.arxiv.org/api/query?search_query=all:astro&start=0&max_results=1000'   data = urllib.urlopen(url).read() soup = BeautifulStoneSoup(data) #print(soup.prettify()) #list = soup.findAll('arxiv:affiliation') #for i in range(len(list)): #        print list[i].contents   test = [tag.string for tag in soup.findAll('arxiv:aiffiliation')] Now, the problem I'm having is that I'm getting affiliation of all authors which I want to split into sets of affiliations of authors of a paper, which I'm stuck on at the moment. Once I get that part, I can move on to the next part of this pet project, displaying these
Read more

Farewell to Enthought

I started my professional career at Enthought , at the Pune office in India, on Feb 29, 2016. Over the course of eight long years, I spent time at the Austin office in the US, the Cambridge office in the UK, and I worked remotely from India. I was let go on March 27, 2024 . I had an unbelievably great time. I had three amazing mentors - Pankaj Pandey, Senganal Thirunavukkarasu, and Mark Dickinson. Pankaj mentored me in my first year at Enthought. I started paying attention to the craft of software after working with him. Senganal started mentoring me in my second year at Enthought, and continues to mentor me, even after the both of us have moved on from Enthought. He instilled professionalism in me, ensuring that the code I wrote produced precise scientific results, and that I tackled the known unknown aspects of a project first, to ensure timely communication about project progress. I was eager to manage people at the time and Senganal made me realize that I didn't want to manage
Read more

Elementary (particle physics), my dear Watson

Ground Control to Major Tom:  Shruti Patel checking in. Since my dear friend and fellow-physicist Rahul Poruri is homeward bound, and shall remain there for a week, I'm stepping in to continue his tradition of daily posts to Astronut . Even as I write, I'm not quite sure what this post is going to be about, so please forgive me for occasional rants and digressions.  By the way Rahul, I totally resent you for the name of this blog- I'm never going to start my own blog because there's no way I'll come up with a name as cool as Astronut! For now, I shall try and be happy with being a guest writer! Before I begin, a little bit on who I am and what I do; so that you can trust that my general views on science- particle physics in particular- are not entirely baseless. I graduated with a masters in Physics from IIT Madras in July this year, and I'm currently working towards (an eventual) PhD with the Theory Group at the Deutsches Electronen-Synchrotron (DESY)
Read more