.NET Design Patterns

Solutions approach

We will divide the requirement into the two following parts:

• A library for evaluating arbitrary mathematical expressions
• An application which will consume the aforementioned library to plot data

The expression evaluator library requirements can be enumerated as follows:

• Modeling expressions as AST
• Writing a lexical analyzer
• Writing a recursive descent parser
• Depth first walk of the tree
• Supporting trigonometric functions and pseudo variable ($)
• Packaging everything as a facade pattern-based API

The application requirements can be enumerated as follows:

• A screen with a WPF 2D graphics surface
• A prompt for entering expressions
• Implementation of the observer for detecting a new plot request
• Passing the value to the expressions library for change ...