A calculator for evaluating nested mathematical expressions written in English

This is a simple calculator through which mathematical expressions could be evaluated and results sent back to the console. Main mathematical functions which are catered are as under

1. Addition
2. Subtraction
3. Multiplication
4. Division

Apart from these, there is another expression called let which is used for assigning data to a variable and then using it for evaluating further mathematical functions.

Some of the example inputs and respective output is given below:

• The general expression is in the format => expr(subExpr ...) where expr is an expression and subExpr... are multiple sub-expressions within an expression.
• A sub-expression can be either a number of an expression
  1. add(1, 3) => expr == add( and subExpr.. == [1, 2]
  2. mult(sub(1, 3), 3) => expr == mult( and subExpr.. == [sub(1, 3), 3]
• A let operator for assigning values to variables
  1. let(variable, value, expression(variable))
  2. let(a, 5, add(a, a)) => variable == a and value == 5 and expression(variable) == add(a, a)

1. Validate the expression and trim any spaces
2. Extract an isolated block from an expression and evaluation that block recursively.
3. Base cases are the direct mathematical evaluations. add(5, 3) is a base case since it would return mathematical result rather than expression.
4. Starting point is to identify the mathematical expression so which would be the first evaluation in recursion.
5. evaluation of add(expression1, expression2) is equvivalant to evaluation of expression1(subExpr...) + expression1(subExpr2...)

java -jar simple-calculator-0.0.1-SNAPSHOT.jar arg1 arg2 where:

• arg1 = Mathematical Expression (let(a, 5, add(a, a)))
• arg2 = Log Level (ERROR, WARN, INFO, DEBUG, TRACE, ALL)

• IntelliJ - IDE used for Development
• Java - Project development language
• Travis CI - CI for the project

• Muhammad Umer

This project is licensed under the MIT License - see the LICENSE file for details