Ruby arithmetic calculator

A basic arithmetic calculator implemented in Ruby

Consists of:

• Lexer (converts input string to array of tokens)
• Parser (converts array of tokens to RPN)
• Evaluator (evaluates RPN expression)

Supports following arithmetic operations:

• + (addition)
• - (subtraction)
• / (division)
• * (multiplication)
• ^ (exponentiation)
• log (taking the logarithm)

Usage:

ruby app.rb [expression]

Example:

ruby app.rb "log 100 10 * ((4 - 7) ^ (3 + 1) / 4)"