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Expression.cs
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using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using System.Reflection;
using System.Reflection.Emit;
using System.Threading;
using System.Collections.ObjectModel;
using System.Text;
namespace Wfccm2
{
/// <summary>
/// Evaluatable mathmatical function.
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// Takes a string and allow a user to add variables. Evaluates the string as a mathmatical function.
/// 11 Jan 2006 - Will Gray
/// - Added generic collection implementation.
/// </pre></remarks>
[Serializable()]
public class Expression : MarshalByRefObject
{
/// <summary>
/// Dynaamic function type.
/// </summary>
/// <remarks><pre>
/// 20 Dec 2005 - Jeremy Roberts
/// </pre></remarks>
[Serializable()]
public abstract class DynamicFunction
{
public abstract double EvaluateD(Dictionary<string, double> variables);
public abstract bool EvaluateB(Dictionary<string, double> variables);
}
protected DynamicFunction dynamicFunction;
//protected AppDomain NewAppDomain;
#region Class variable
//class Variable
//{
// public string name;
// public double val;
//}
#endregion
#region Member data
protected string inFunction = string.Empty; // Infix function.
protected string postFunction = string.Empty; // Postfix function.
protected Dictionary<string, double> variables = new Dictionary<string, double>();
protected const double TRUE = 1;
protected const double FALSE = 0;
protected string[] splitPostFunction;
private bool compilecode = false;
#endregion
~Expression()
{
//NewAppDomain.;
}
#region Constructors
/// <summary>
/// Creation constructor.
/// </summary>
/// <remarks><pre>
/// 20 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
public Expression()
{
}
/// <summary>
/// Creation constructor.
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
/// <param name="function">The function to be evaluated.</param>
public Expression(string function)
{
this.Function = function;
}
///// <summary>
///// Copy constructor.
///// </summary>
///// <remarks><pre>
///// 19 Jul 2004 - Jeremy Roberts
///// </pre></remarks>
///// <param name="function">The function to be evaluated.</param>
//public Expression(Expression cloneMe)
//{
// this.Function = cloneMe.Function;
// foreach (string key in cloneMe.variables.Keys)
// {
// this.AddSetVariable(key, (double)cloneMe.variables[key]);
// }
//}
#endregion
#region properties
/// <summary>
/// InFix property
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
public string Function
{
get { return this.inFunction; }
set {
// This will throw an error if it does not validate.
this.Validate(value);
// Function is valid.
this.inFunction = value;
this.postFunction = this.Infix2Postfix(this.inFunction);
this.splitPostFunction = postFunction.Split(new char[] { ' ' });
this.ClearVariables();
if (this.compilecode)
this.compile();
}
}
/// <summary>
/// PostFix property
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
public string PostFix
{
get { return postFunction; }
}
/// <summary>
/// PostFix property
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
public string InFix
{
get { return this.Expand(inFunction); }
}
public bool Compile
{
get { return this.compilecode; }
set { this.compilecode = value; }
}
#endregion
/// <summary>
/// Convecs an infix string to a post fix string.
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
/// <param name="func">The function to convert</param>
/// <returns>A post fix string.</returns>
protected string Infix2Postfix(string func)
{
func = this.Expand(func);
string[] inFix = func.Split(new char[]{' '});
Stack<string> postFix = new Stack<string>();
// inFix = evaluateLogic(inFix);
Stack<string> operators = new Stack<string>();
string currOperator;
foreach (string token in inFix)
{
// If the token is an operand
if (this.IsOperand(token))
{
//push on the postfix vector
postFix.Push(token);
}
// If the token is a "("
else if (token == "(")
{
//push on the operatorVector
operators.Push(token);
}
// If the token is a ")"
else if (token == ")")
{
// pop the operatorVector and store operator
currOperator = operators.Pop();
// while operator is not a "("
while (currOperator != "(")
{
// push the operator on the postfixVector
postFix.Push(currOperator);
// pop the operatorVector and store operator
currOperator = operators.Pop();
}
}
// If the token is an operator
else if (this.IsOperator(token))
{
// while precedence of the operator is <= precedence of the token
while (operators.Count > 0)
{
if (this.GetPrecedence(token) <= this.GetPrecedence(operators.Peek()))
{
// pop the operatorVector and store operator
currOperator = operators.Pop();
//push operator on the postfix vector
postFix.Push(currOperator);
}
else
break;
}
//push token on the postfix vector
operators.Push(token);
}
}
// while operatorVector is not empty
while (operators.Count > 0)
{
// pop the operatorVector and store operator
currOperator = operators.Pop();
//push operator on the postfix vector
postFix.Push(currOperator);
}
// Build the post fix string.
string psString = string.Empty;
foreach (string item in postFix)
{
psString = item + " " + psString;
}
psString = psString.Trim();
return psString;
}
/// <summary>
/// Checks to see if a string is an operand.
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
/// <param name="token">String to check</param>
/// <returns></returns>
protected bool IsOperand(string token)
{
if (!this.IsOperator(token) &&
token != "(" &&
token != ")" &&
token != "{" &&
token != "}")
return true;
else
return false;
}
/// <summary>
/// Checks to see if a string is an operator.
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
/// <param name="token">String to check</param>
/// <returns></returns>
protected bool IsOperator(string token)
{
if (token == "+" ||
token == "-" ||
token == "*" ||
token == "/" ||
token == "^" ||
token == "&&" ||
token == "||" ||
token == "sign" ||
token == "abs" ||
token == "neg" ||
token == "==" ||
token == ">=" ||
token == "<=" ||
token == ">" ||
token == "<" ||
token == "!=")
return true;
else
return false;
}
/// <summary>
/// Expandn the spaces around operators and operands.
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
/// <param name="function">Function to expand.</param>
/// <returns></returns>
public string Expand(string function)
{
// Clean the function.
function = Regex.Replace(function, @"[ ]+", @"");
function = function.Replace("(", " ( ");
function = function.Replace(")", " ) ");
function = function.Replace("+", " + ");
function = function.Replace("-", " - ");
function = function.Replace("*", " * ");
function = function.Replace("/", " / ");
function = function.Replace("^", " ^ ");
function = function.Replace("||", " || ");
function = function.Replace("&&", " && ");
function = function.Replace("==", " == ");
function = function.Replace(">=", " >= ");
function = function.Replace("<=", " <= ");
//function = function.Replace("<", " < ");
function = Regex.Replace(function, @"<([^=]|$)", @" < $1");
//function = function.Replace(">", " > ");
function = Regex.Replace(function, @">([^=]|$)", @" > $1");
function = function.Replace("!=", " != ");
function = function.Replace("sign", " sign ");
function = function.Replace("abs", " abs ");
function = function.Replace("neg", " neg ");
function = function.Trim();
function = Regex.Replace(function, @"[ ]+", @" ");
// Find and correct for scientific notation
function = Expression.ScientificNotationCorrection(function);
// Fix negative real values. Ex: "1 + - 2" = "1 + -2". "1 + - 2e-1" = "1 + -2e-1".
function = Regex.Replace(
function,
@"([<>=/*+(-] -|sign -|^-) (\d+|[0-9]+[eE][+-]\d+)(\s|$)",
@"$1$2$3");
return function;
}
// Corrects for spaced function...
/// <summary>
/// Corrects scientific notation in an expression.
/// </summary>
/// <param name="function">The expanded function to check.</param>
/// <returns>The corrected expanded function</returns>
public static string ScientificNotationCorrection(string function)
{
char[] ops = {'-','+'};
int n = function.IndexOfAny(ops,0);
while ((n <= function.Length) && (n > -1))
{
// Find the previous space.
int prevCut=-1;
int nextCut=-1;
if (n-2 <= 0)
prevCut = 0;
else
prevCut = function.LastIndexOf(" ", n-2, n-2) + 1;
//prevCut = n-2 <= 0 ? 0 : function.LastIndexOf(" ", n-2, n-2) + 1;
//prevSpace = function.LastIndexOf(" ", n-2, n-2);
if (n + 2 < function.Length)
nextCut = function.IndexOf(" ", n+2);
else
nextCut = function.Length;
nextCut = (nextCut == -1 ? function.Length : nextCut);
string checkMeSpace = function.Substring(prevCut, nextCut - prevCut);
string checkMe = checkMeSpace.Replace(" ", string.Empty);
bool realValue=false;
double val = Double.NaN;
try
{
val = Double.Parse(checkMe);
realValue = true;
}
catch {}
if (realValue)
{
function = function.Replace(checkMeSpace, checkMe);
//n = n - checkMeSpace.Length + checkMe.Length;
n = prevCut + checkMe.Length-1;
}
n = function.IndexOfAny(ops,n+1);
}
return function;
}
/// <summary>
/// Returns the precedance of an operator.
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
/// <param name="token">Token to check.</param>
/// <returns></returns>
protected int GetPrecedence(string token)
{
if (
token == "+" ||
token == "-" ||
token == "||" )
return 1;
else if (
token == "*" ||
token == "/" ||
token == "&&")
return 2;
else if (
token == "==" ||
token == ">=" ||
token == "<=" ||
token == ">" ||
token == "<" ||
token == "!=" ||
token == "sign" ||
token == "^" )
return 3;
else if (
token == "abs" ||
token == "neg")
return 4;
else
return 0;
}
/// <summary>
/// Adds or sets a Variable.
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
/// <param name="name">Variable name.</param>
/// <param name="value">Variabale value.</param>
public void AddSetVariable(string name, double val)
{
variables[name] = val;
}
/// <summary>
/// Adds or sets a Variable.
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
/// <param name="name">Variable name.</param>
/// <param name="value">Variabale value.</param>
public void AddSetVariable(string name, bool val)
{
double dval;
if (val)
dval = 1;
else
dval = 0;
variables[name] = dval;
}
/// <summary>
/// Clears the variable information.
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
public void ClearVariables()
{
variables.Clear();
}
/// <summary>
/// Clears all information.
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
public void Clear()
{
inFunction = string.Empty;
postFunction = string.Empty;
variables.Clear();
}
/// <summary>
/// Checks to see if a string is a variable.
/// </summary>
/// <remarks><pre>
/// 20 Jul 2004 - Jeremy Roberts
/// 11 Aug 2004 - Jeremy Roberts
/// Changed to check to see if it is a number.
/// </pre></remarks>
/// <param name="token">String to check.</param>
/// <returns></returns>
protected bool IsVariable(string token)
{
//if (isOperator(token))
// return false;
if (token == "true" || token == "false")
return false;
if (!this.IsOperand(token))
return false;
if (this.IsNumber(token))
return false;
return true;
}
public ReadOnlyCollection<string> FunctionVariables
{
get
{
// Check to see that the function is valid.
if (this.inFunction.Equals(string.Empty) || this.inFunction == null)
throw new Exception("Function does not exist");
// Expand the function.
string func = this.Expand(inFunction);
// Tokenize the funcion.
string[] inFix = func.Split(new char[] { ' ' });
// The arraylist to return
List<string> retVal = new List<string>();
// Check each token to see if its a variable.
foreach (string token in inFix)
{
if (this.IsVariable(token))
retVal.Add(token);
}
return retVal.AsReadOnly();
}
}
/// <summary>
/// Returns a variable's value.
/// </summary>
/// <remarks><pre>
/// 20 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
/// <param name="token">Variable to return.</param>
/// <returns></returns>
public double GetVariableValue(string token)
{
try
{
return variables[token];
}
catch
{
return double.NaN;
}
}
protected bool Validate(string inFix)
{
string inFixClean = this.Expand(inFix);
string[] func = inFixClean.Split(new char[]{' '});
// Check parenthesis
int parCount = 0;
for ( int i = 0; i < func.Length; i++){
// Make sure the abs function is formatted correctly.
if (func[i] == "abs")
{
if (i == func.Length - 1)
throw new Exception("Operator error! abs does not have a \"(\"" + inFix);
else if ((string)func[i+1] != "(")
throw new Exception("Operator error! abs does not have a \"(\"" + inFix);
}
// Make sure the neg function is formatted correctly.
if (func[i] == "neg")
if (i != 0)
if (this.IsOperand(func[i-1]))
throw new Exception("Operator error! neg used improperly." + inFix);
if (i > 0 && i < func.Length - 1)
if (func[i] == "(" || func[i] == ")")
if (this.IsOperand(func[i-1]) && this.IsOperand(func[i+1]))
throw new Exception("Operator error!" + func[i] + " used improperly." + inFix);
if (func[i] == "(")
parCount++;
else if (func[i] == ")")
parCount--;
if (parCount < 0)
// TODO: Make the exception better.
throw new Exception("Parenthesis error! No matching opening parenthesis." + " " + inFix);
}
if (parCount != 0)
// TODO: Make the exception better.
throw new Exception("Parenthesis error! No matching closeing parenthesis." + " " + inFix);
// Check operators
// Create a temporary vector to hold the secondary stack.
Stack<string> workstack = new Stack<string>();
func = this.Infix2Postfix(inFix).Split(new char[]{' '});
// loop through the postfix vector
string token = string.Empty;
for (int i = 0; i < func.Length; i++)
{
token = func[i];
// If the current string is an operator
if (this.IsOperator(token))
{
if (token == "abs" ||
token == "neg" ||
token == "sign")
{
try
{
workstack.Pop();
workstack.Push("0");
}
catch
{
throw new Exception("Operator error! \"" + token + "\". " + inFix);
}
}
else
{
try
{
workstack.Pop();
workstack.Pop();
workstack.Push("0");
}
catch
{
throw new Exception("Operator error! \"" + token + "\". " + inFix);
}
}
}
else
{
// push the string on the workstack
workstack.Push(token);
}
}
// Check to see if the value on the back is a variable.
//return convertString((string)workstack.Peek());
return true;
}
/// <summary>
/// Evaluates the funcion as for a double.
/// </summary>
/// <remarks><pre>
/// 19 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
/// <returns></returns>
public double EvaluateD()
{
if (dynamicFunction != null)
return dynamicFunction.EvaluateD(variables);
// TODO! Check to see that we have the variable that we need.
// Create a temporary vector to hold the secondary stack.
Stack<string> workstack = new Stack<string>();
string sLeft;
string sRight;
double dLeft = 0;
double dRight = 0;
double dResult = 0;
//this.splitPostFunction = postFunction.Split(new char[] { ' ' });
// loop through the postfix vector
string token = string.Empty;
for (int i = 0, numCount = this.splitPostFunction.Length; i < numCount; i++)
{
token = this.splitPostFunction[i];
// If the current string is an operator
if (this.IsOperator(token))
{
// Single operand operators.
if (token == "abs" ||
token == "neg" ||
token == "sign")
{
// Get right operand
sLeft = workstack.Pop();
// Convert the operands
dLeft = this.ConvertString(sLeft);
}
// Double operand operators
else
{
// Get right operand
sRight = workstack.Pop();
// Get left operand
sLeft = workstack.Pop();
// Convert the operands
dLeft = this.ConvertString(sLeft);
dRight = this.ConvertString(sRight);
}
// call the operator
switch (token)
{
case "+":
// Add the operands
dResult = dLeft + dRight;
break;
case"-":
// Add the operands
dResult = dLeft - dRight;
break;
case "*":
// Multiply the operands
dResult = dLeft * dRight;
break;
case "/":
// Divide the operands
if (dRight == 0)
dResult = double.NaN;
else
dResult = dLeft / dRight;
break;
case "^":
// Raise the number to the power.
dResult = Math.Pow(dLeft, dRight);
break;
case "sign":
// Get the sign.
dResult = dLeft >= 0 ? 1 : -1;
break;
case "abs":
// Convert to postive.
dResult = Math.Abs(dLeft);
break;
case "neg":
// Change the sign.
dResult = -1 * dLeft;
break;
}
// Push the result on the stack
workstack.Push(dResult.ToString());
}
else
{
// push the string on the workstack
workstack.Push(token);
}
}
// Check to see if the value on the back is a variable.
return this.ConvertString(workstack.Peek());
}
/// <summary>
/// Converts a string to its value representation.
/// </summary>
/// <remarks><pre>
/// 20 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
/// <param name="token">The string to check.</param>
/// <returns></returns>
protected double ConvertString(string token)
{
try
{
return variables[token];
}
catch
{
if (token == "true")
return TRUE;
else if (token == "false")
return FALSE;
else
// Convert the operand
return double.Parse(token);
}
/*
// If operand is a variable
if (this.IsVariable(token))
// Get variable value
return this.GetVariableValue(token);
else if (token == "true")
return TRUE;
else if (token == "false")
return FALSE;
else
// Convert the operand
return double.Parse(token);
*/
}
/// <summary>
/// Overloads the ToString method.
/// </summary>
/// <remarks><pre>
/// 20 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
/// <param name="token">The string to check.</param>
/// <returns></returns>
public override string ToString()
{
StringBuilder ret = new StringBuilder();
ret.Append(inFunction);
int count = 0;
foreach (KeyValuePair<string,double> keyval in variables)
{
if (count++ == 0)
ret.Append("; ");
else
ret.Append(", ");
ret.Append(keyval.Key + "=" + keyval.Value);
}
return ret.ToString();
}
/// <summary>
/// Evaluates the function given as a boolean expression.
/// </summary>
/// <remarks><pre>
/// 20 Jul 2004 - Jeremy Roberts
/// </pre></remarks>
public bool EvaluateB()
{
if (dynamicFunction != null)
return dynamicFunction.EvaluateB(variables);
// TODO! Check to see that we have the variable that we need.
// Create a temporary vector to hold the secondary stack.
Stack<string> workstack = new Stack<string>();
string sLeft = string.Empty;
string sRight = string.Empty;
string sResult = string.Empty;
double dLeft = 0;
double dRight = 0;
double dResult = 0;
string[] func = postFunction.Split(new char[]{' '});
// loop through the postfix vector
string token = string.Empty;
for (int i = 0; i < func.Length;i++)
{
token = func[i];
// If the current string is an operator
if (this.IsOperator(token))
{
// Single operand operators.
if (token == "abs" ||
token == "neg")
{
// Get right operand
sLeft = workstack.Pop();
// Convert the operands
dLeft = this.ConvertString(sLeft);
}
// Double operand operators
else
{
// Get right operand
sRight = workstack.Pop();
// Get left operand
sLeft = workstack.Pop();
// Convert the operands
dLeft = this.ConvertString(sLeft);
dRight = this.ConvertString(sRight);
}
// call the operator
switch (token)
{
case "<=":
// Make the comparison.
if (dLeft <= dRight)
sResult = "true";
else
sResult = "false";
break;
case "<":
// Make the comparison.
if (dLeft < dRight)
sResult = "true";
else
sResult = "false";
break;
case ">=":
// Make the comparison.
if (dLeft >= dRight)
sResult = "true";
else
sResult = "false";
break;
case ">":
// Make the comparison.
if (dLeft > dRight)
sResult = "true";
else
sResult = "false";
break;
case "==":
// Get right operand
// Make the comparison.
if (dLeft == dRight)
sResult = "true";
else
sResult = "false";
break;
case "!=":
// Make the comparison.
if (dLeft != dRight)
sResult = "true";
else
sResult = "false";
break;
case "||":
// OR the operands.
if (dRight == TRUE || dLeft == TRUE)
sResult = "true";
else
sResult = "false";
break;
case "&&":
// AND the operands
if (dRight == TRUE && dLeft == TRUE)
sResult = "true";
else
sResult = "false";
break;
case "abs":
// Convert to postive.
dResult = Math.Abs(dLeft);
sResult = dResult.ToString();
break;
case "neg":
// Convert to postive.
dResult = -1 * dLeft;
sResult = dResult.ToString();
break;
}
// Push the result on the stack
workstack.Push(sResult);
}
else
{
// push the string on the workstack
workstack.Push(token);
}
}
//if (workstack.back() == "true")
// return true;
//else
// return false;
if (this.ConvertString(workstack.Peek()) == TRUE)
return true;