#Spreadsheet

##Overview A spreadsheet is an interactive table for storing, analyzing and processing data. A cell can contain numbers, operators, braces and references to other cells. A spreadsheet dynamically evaluates value in each cell.

##Main window The main window contains editable grid, text field to display entered formula in focused cell and button to toggle Formulas mode.

##Supported operations

• Addition '+'

• Subtraction '-'

• Multiplication '*'

• Division '/'

• Power '^'

• Bitwise AND '&' and OR '|'

##Reference format A reference is a latin letter, followed by number from 1 to 99.

##Long arithmetic Long arithmetic is used to avoid integer overflow.

##Operators precedence Operators precedence are respected.

##Formulas Mode When Formulas Mode is toggled, cells display originally typed formula instead of evaluated value.

Text parsing

A Lexer is implemented in order to parse text. The Lexer uses regular expressions and named capturing groups to extract information from entered text.

##Algorithms

• Tarjan's algorithm to detect cycled references
• Topological sorting to determine in what order evaluate cells
• Shunting-yard algorithm to evaluate expression and respect precedence and braces

######Copyright © 2016 by Vitaliy Kononenko, K-24