Formula Prompt

This library let's you define formulas that you can later evaluate in your command line. I use this library for school work that requires repetitive calculations or calculations needing a computer.

Example

Here I define two formulas. Notice the @register_formula(...) decorator that registers the formulas with the library.

from formula_prompt import *

@register_formula([NumInput("side length")])
def volume_of_cube(s):
  return s ** 3

@register_formula([NumInput("length"), NumInput("width")])
def area_of_rectangle(length, width):
  return length * width

Now that the library has registered the formulas, I can launch the prompt.

launch_prompt()

The prompt lets you pick a formula and evaluate it.

0:	area_of_rectangle
1:	volume_of_cube
2:	quit
Pick a formula:
>>> 1
Input side length:
>>> 3
volume_of_cube:
27.0

For more examples, look at the /examples folder on GitHub.

How to use this library

1. Install the library by running: pip install formula-prompt

2. Write your formulas (see example above).

3. Add the @register_formula(...) decorator (see below).

4. Call launch_prompt().

Using @register_formula(...)

@register_formula(...) is a decorator that takes in a few parameters.

name	Required	Description
func_inputs	Yes	A list of objects describing the inputs to your formula (see allowed formula inputs section below).
decimal_places	No. Defaults to 4.	Decimal places to round the results of your formula to. Specify None to disable rounding.
name	No. Defaults to the function name.	Lets you set the name that will be displayed in the prompt. Names containing dots (.) will be considered folders. For example, volumes.cube will place the formula in a volumes folder and display the formula as cube.

Allowed formula inputs

You can specify three types of inputs.

• NumInput: For inputs that accepts a single floating-point number.

• IntInput: For inputs that accept a single integer.

• ListInput: For inputs that accept a list of floating-point numbers.

You can use optional=True to allow skipping the input (this will pass None to your function).

Here's an example.

@register_formula([
    IntInput("first optional input", optional=True),
    NumInput("second non-optional input")
])
def some_funtion(first_integer_input, second_float_input):
    ...

You can also make a custom input type by creating a class that inherits from Inputs. See inputs.py.