public MathExpressions()
{
var first = new Expression();
Expressions.Add(first);
_instance = this;
}
public void Add()
{
var a = new Expression();
Expressions.Add(a);
}
private void NotifyDependentExpressions(Expression source)
{
foreach (Expression e in dependentExpressions.ToList())
{
e.ParseExpression(source);
}
}
public void RemoveDependentExpression(Expression e)
{
dependentExpressions.Remove(e);
}
public void ParseExpression(Expression source = null)
{
try
{
if (!String.IsNullOrEmpty(Name) && Parser.PrimaryContext.AllVariables.ContainsKey(Name)) // Remove old value from parser
{
Parser.RemoveVariable(Name);
}
var parser = Parser.Parse(ExpressionString);
var usedSymbols = parser.Context.Parser.CollectedSymbols;
var dependsOn = MathExpressions.Instance.Expressions.Where(s => usedSymbols.Contains(s.Name)).ToList(); // Get expressions that are used by this expression.
UpdateDependentOn(dependsOn);
if (source == this) // Detecs infinite dependency loop.
{
Result = null;
ErrorMessage = "Error. Infinite dependecy loop.";
NotifyDependencyLoop();
return;
}
if (source == null)
source = this;
var result = parser.Execute();
if (!String.IsNullOrEmpty(Name)) // Variable must be named to be aded to parser
{
Parser.AddVariable(Name, result);
}
Result = result;
ErrorMessage = null;
NotifyDependentExpressions(source);
}
catch (Exception e)
{
ErrorMessage = e.Message;
Result = null;
NotifyDependentExpressions(source);
}
}
public void NotifyDependencyLoop(Expression source = null)
{
if (source == null || source != this)
{
if (source == null)
source = this;
Result = null;
ErrorMessage = "Error. Infinite dependecy loop.";
foreach (Expression e in dependentExpressions.ToList())
{
e.NotifyDependencyLoop(source);
}
}
}
public void AddDependentExpression(Expression e)
{
if (e != this && !dependentExpressions.Contains(e))
dependentExpressions.Add(e);
}