|
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using InterpreterPattern.NonterminalExpressions;
using InterpreterPattern.TerminalExpression;
using InterpreterPattern.ExpressionBase;
//http://www.blackwasp.co.uk/Interpreter.aspx
namespace InterpreterPattern
{
class Program
{
static void Main(string[] args)
{
var parser = new Parser();
var commands = new string[]
{
"+ 5 6",
"- 6 5",
"+ - 4 5 6",
"+ 4 - 5 6",
"+ - + - - 2 3 4 + - -5 6 + -7 8 9 10"
};
foreach (var command in commands)
{
ExpressionBase.IExpressionBase expression = parser.Parse(command);
Console.WriteLine("{0} = {1}", expression, expression.Evaluate());
}
}
}
public class Parser
{
public ExpressionBase.IExpressionBase Parse(string polish)
{
var symbols = new List<string>(polish.Split(' '));
return ParseNextExpression(symbols);
}
public ExpressionBase.IExpressionBase ParseNextExpression(List<string> symbols)
{
int value;
if (int.TryParse(symbols[0], out value))
{
symbols.RemoveAt(0);
return new IntegerExpression(value);
}
return ParseNonTerminalExpression(symbols);
}
private ExpressionBase.IExpressionBase ParseNonTerminalExpression(List<string> symbols)
{
var symbol = symbols[0];
symbols.RemoveAt(0);
var expr1 = ParseNextExpression(symbols);
var expr2 = ParseNextExpression(symbols);
switch (symbol)
{
case "+":
return new AdditionExpression(expr1, expr2);
case "-":
return new SubtractionExpression(expr1, expr2);
default:
string message = string.Format("Invalid Symbol ({0})", symbol);
throw new InvalidOperationException(message);
}
}
}
}
|
By viewing downloads associated with this article you agree to the Terms of Service and the article's licence.
If a file you wish to view isn't highlighted, and is a text file (not binary), please
let us know and we'll add colourisation support for it.
My name is Robert Kanasz and I have been working with ASP.NET, WinForms and C# for several years.
MCSD - Web Applications
MCSE - Data Platform
MCPD - ASP.NET Developer 3.5
- Web Developer 4
MCITP - Database Administrator 2008
- Database Developer 2008
MCSA - SQL Server 2012
MCTS - .NET Framework 3.5, ASP.NET Applications
- SQL Server 2008, Database Development
- SQL Server 2008, Implementation and Maintenance
- .NET Framework 4, Data Access
- .NET Framework 4, Service Communication Applications
- .NET Framework 4, Web Applications
MS - Programming in HTML5 with JavaScript and CSS3 Specialist
Open source projects:
DBScripter - Library for scripting SQL Server database objects
Please, do not forget vote