CalScript Calculator

A C++ command-line calculator capable of evaluating complex mathematical expressions, managing variables, and defining custom functions. This tool leverages an efficient token-based parsing system based upon the shunting-yard algorithm for accurate numerical calculations.

Building the Project

This project requires C++17 or above for features like std::optional and std::string_view.

g++ -std=c++17 -I include src/*.cpp -o calscript

Run the executable to start the calculator.

Core Features

Constants

Built-in mathematical constants:

• pi - Pi (3.14159...)
• e - Euler's number (2.71828...)
• phi - Golden ratio (1.61803...)
• sqrt2 - Square root of 2 (1.41421...)
• ans - Result of the last calculation

Mathematical Functions

• sin(x) - Sine (in degrees)
• cos(x) - Cosine (in degrees)
• tan(x) - Tangent (in degrees)
• log(x) - Base-10 logarithm
• ln(x) - Natural logarithm
• sqrt(x) - Square root

Operators

In order of precedence:

1. ! - Factorial
2. ^ - Exponentiation
3. *, /, % - Multiplication, Division, Modulo
4. +, - - Addition, Subtraction

Implicit Multiplication

The parser intelligently recognizes:

• 2(3) evaluates to 6
• 4pi evaluates to 4 * pi
• 2sin(30) evaluates to 2 * sin(30)
• (2+3)(4+5) evaluates to (2+3) * (4+5)

Variable Management

Defining Variables

def [variable_name] [expression]

Example:

def radius 5
def area pi*radius^2

Updating Variables

upd [variable_name] [expression]

Example:

upd radius 10
upd area pi*radius^2

Custom Functions

Defining Functions

create func [name]([param1], [param2], ...): [expression]

Example:

create func area(r): pi*r^2
create func hypotenuse(a, b): sqrt(a^2 + b^2)

Using Functions

Functions can be called directly:

area(5)
hypotenuse(3, 4)

Utility Commands

Listing Information

• ls vars - Display all defined variables
• ls hist - Show calculation history
• ls funcs - List all defined functions

Deletion Commands

• del [variable_name] - Delete a specific variable
• del func [function_name] - Delete a function
• del vars - Delete all variables
• del hist - Clear calculation history

System Commands

• exit - Close the calculator
• clear - Clear the screen

Examples

Basic Arithmetic

2 + 3 * 4     # Returns 14
(2 + 3) * 4   # Returns 20

Using Built-in Functions

sin(30)       # Returns 0.5
log(100)      # Returns 2

Variable Operations

def radius 5
pi * radius^2  # Calculate circle area = 78.54
def area ans   # Save result to variable

Custom Functions

create func circle_area(r): pi*r^2
circle_area(5)  # Returns 78.54

create func quad(a, b, c, x): a*x^2 + b*x + c
quad(1, -3, 2, 2)  # Returns 0

Complex Calculations

create func normal_pdf(x, mean, std): (1/(std*sqrt(2*pi)))*e^(-0.5*((x-mean)/std)^2)
normal_pdf(0, 0, 1)  # Returns 0.3989 (standard normal at peak)

Current Limitations

• No control structures (if/else, loops)
• No array/list support
• Limited symbolic manipulation capabilities
• Simple text-based interface

Best Practices

1. Use parentheses to clarify operator precedence in complex expressions
2. Always use parentheses with function calls for clarity
3. Use descriptive variable and function names
4. Break complex calculations into smaller parts using intermediate variables

Error Handling

The calculator provides error messages for:

• Syntax errors
• Undefined variables/functions
• Division by zero
• Invalid function arguments
• Mismatched parentheses