Calculators

Can we write a universal calculator repository? Looks like we can!

To run

1. Install libraries, see requirements.txt section below.

   a. If you're using a virtualenv, activate it before running

2. Run! From the top level of the repository, python run.py [--debug]

Calculators

The calculators that are currently defined are Compound Interest and Body Mass Index.

Calculators can be added to Calculators/templates/formulae.

To render the calculator, point the app at the formula file, e.g. localhost:8080/compound_interest for compound_interest.formula, localhost:8080/BMI for BMI.formula. Currently, localhost:8080/ renders the compound interest calculator.

Important files

- requirements.txt
- run.py
- Calculators
    - __init__.py
    - helpers.py
    - models
        - calculator.py
    - templates
        - calculator.html
        - formulae
            - BMI.formula
            - compound_interest.formula
    - views
        - calculator
            - Calculator.py
        - endpoint
            - Endpoint.py

requirements.txt

Python libraries used by the app. To install them, run pip install -r requirements. We suggest using a virtual environment so that you don't have to install the libraries system-wide. This would look something like

virtualenv .env
. ./.env/bin/activate
pip install -r requirements.txt

run.py

Used to run the app. Takes an optional command line argument --debug to enable Flask debug mode.

Calculators/__init__.py

Contains the Flask app variable and some setup code

Calculators/helpers.py

Contains helper functions. Currently, the only helper function is get_template_variables, which reads a Jinja2 template representing a calculator formula and returns the variables that need to be filled in.

Calculators/models/calculator.py

Contains an SQLAlchemy declarative definition of the database tables for this app.

templates/calculator.html

The template file for a generic calculator.

templates/formulae

Contains .formula files, which define a specific calculator.

views

Sets up different endpoints for the app.

view/calculator/Calculator.py

Defines the index page of the app, which renders a calculator as a form.

view/endpoint/Endpoint.py

Defines the API for the app.

Remaining work, in no particular order

• Fix up all of the TODOs
• Make the form pretty
• Create some unit tests
• Add a backend for formula maintenance. I'm imagining a code editor, easily adding and removing tags, etc.