Flee Forum Rss Feed

New Post: Support Nullable type?

rli — Thu, 15 Oct 2009 14:46:14 GMT

We use flee in our project. In our project, we have expressions with variables of nullable datatype. We get error when using flee to evaluate such expressions. For example, for expression (dtReportDate >= DateTime.Parse("2008-11-01")), dtReportDate is a variable of type DateTime?(nullable datetime). When using flee to evaluate it, it reported error: Unhandled Exception: Ciloci.Flee.ExpressionCompileException: CompareElement: Operation 'GreaterThanOrEqual' is not defined for types 'Nullable'1' and 'DateTime'. Yet C# compiler has no problem to compile such nullable type.

Is there a way to fix the parser in flee to solve this issue?

New Post: Initialize variables in expression

leeatkinson — Fri, 18 Sep 2009 13:29:15 GMT

Is it possible to initalize variables within the string, e.g. something like:

"let a = 10; (cos(a) + sin(a))"

Regards

Lee

New Post: Validating Input

davojc — Wed, 09 Sep 2009 16:22:11 GMT

Was wondering if you had any update?

Thanks

David

New Post: 0333 ! = 333 but it is. Another way around it?

jmaronge — Tue, 01 Sep 2009 22:56:31 GMT

I am running into a problem. I have the following formula, well I simplified this one.

0333 = 333

This always evals to true since 0333 is technically a number. We now I am told that this should not return true since the codes 0333 and 333 would have different meanings. Is there any way to handle this without turning into a string and comparing strings.

I could have an expression that looked like

(0419.45 = 419.45) OR (0419.46 = 419.45) OR (0419.47 = 419.45) OR (0419.48 = 419.45) OR (0419.49 = 419.45) .....etc

I would like to do something like:

(419.45 >= 0419.10) AND (419.45 <= 0419.99) and it still return false. I don't want to have to write out an expression string for each number incrementing my .1 since I could be talking about a range from .1 to 999.

I hope this makes sense.

Thanks for your help,

Jason

New Post: Boolean Variables

rickhodder — Fri, 14 Aug 2009 14:31:47 GMT

try GEN4 = IF(GEN1==TRUE,1,2).

New Post: Boolean Variables

Tester22 — Tue, 11 Aug 2009 19:34:55 GMT

Hello,

I have a situation where we create variables and equations in the admin section and variables will be set with the values when new proposal is created.

For Eg: GEN1,GEN2,GEN3... will be created as boolean type and GEN4 = IF(GEN1=TRUE,1,2).

As equations cannot be compiled with null values , I was setting boolean null variables with string "BOOL". GEN1=\"BOOL\",GEN2=\"BOOL\" and integers with 0. For integers I dont see any problem

but for booleans when I use them in the equations like GEN4 = IF(GEN1=TRUE,1,2) its giving exception as string cannot be compared with boolean.

Do you have any solution to solve the problem?

New Post: How to handle nested expressions?

peringathody — Sat, 08 Aug 2009 04:16:26 GMT

Hi Eciloci,

How can i handle nested expressions in FLEE?

Regards,

Neo

New Post: Suggested enhancements to the CalculationEngine

mindcore — Wed, 22 Jul 2009 23:50:34 GMT

Eugene,

I would like to say that this project is great and that I've been following it for a while and I'm planning on using it in a future project. One aspect of my project will be to give my users an interface to update and change their Formulas. However, I need a Framework that can support this type of interface.

This has led me to some thoughts on ways to make the CalculationEngine in Flee transparent, more agile, and stay fully functional in any project someone wants to use it in.

First, and probably the easiest to implement would be the ability to rename Expressions already loaded to the CalculationEngine. It would need to also do a find and replace on it's precedents and dependents to prevent logic from breaking.

Next, and I don't even know if this will be possible, but create some attributes for properties, and if needed classes, that tie this properties to the CalculationEngine. This would allow users to use Flee's Calculation Engine in any project with extreme ease. This would probably require an interface that the class would have to inherit in order to properly work, but this type of approach would separate someones business layer up from their data layer.

One pit fall that keeps coming up is a way to handle the set method on the tagged property. I know through reflection that it's possible to tie an event to this when the value changes, but I haven't been successful. You would have the same problem if the Expression's name is set by another property.

Thanks for a wonderful project,
MindCore

public class Worksheet : IExpressionContainer 
{ 
     private ExpressionContext _context; 

     // The Expression Attribute could except a string representing 
     // the formula's name or maybe even the name of another 
     // property containing the formula's name.) 
     [Expression("formulaname")] 
     public string Formula { get; set; } 

     // implemented from IExpressionContainer 
     public ExpressionContext Context { get; protected set; } 
}

New Post: Forcing Integer Literals to Double

mjethwa — Mon, 20 Jul 2009 09:17:19 GMT

Many thanks for the support Eugene.

New Post: Forcing Integer Literals to Double

eciloci — Sat, 18 Jul 2009 00:16:26 GMT

The product of the first two numbers is too large for an integer. This causes the product to overflow and product the incorrect result.

You can use the context.Options.IntegersAsDoubles option to force the integer literals to be loaded as doubles. This produces the correct result of 206409.544. This option was put in in v0.9.24.0.

You can also set the context.Options.Checked option to true so that integer overflows will cause an exception instead of being silently truncated.

New Post: Forcing Integer Literals to Double

mjethwa — Thu, 16 Jul 2009 11:41:40 GMT

Hi,

I am using the following code in flee version 0.9.18.0 to evaluate string expressions passed to a function:

poExpContext = New ExpressionContext
poExpOptions = poExpContext.Options

poExpOptions.ResultType = GetType(Double)

poExpContext.Imports.AddType(GetType(Math))

poExp = ExpressionFactory.CreateGeneric(Of Double)(expression, poExpContext)
Evaluate = poExp.Evaluate

I noticed a strange behaviour in the calculations:

If I pass '8833 * 1016000 * 0.000023' it calculates 7687.86816

If I pass '1.0 * 8833 * 1016000 * 0.000023' then it correctly calculates 179486.56

The expressions are intended to be decimal/real calculations. Is there any way of forcing the engine to treat all numeric values as real?

Or is there a fix in the later releases for this issue?

Thanks

Milesh

New Post: Is Variables needed for equations having DateTime?

eciloci — Wed, 08 Jul 2009 18:56:23 GMT

Your datetime variables are being initialized with strings instead of actual datetimes.

It should be like this:

ExpressionContext context = new ExpressionContext();
context.Imports.AddType(typeof(DateTime), "DateTime");

context.Variables.Add("Date1", new DateTime(2010, 1, 1));

context.Variables.Add("Date2", new DateTime(2009, 1, 1));

IDynamicExpression exp = context.CompileDynamic("if(Date1 > Date2,true,false)");
string value = exp.Evaluate().ToString();

The literal notation only works inside an expression since a literal is a constant and would never need to be a variable.

So you could do this:

context.Variables.Add("Date1", new DateTime(2010, 1, 1));

IDynamicExpression exp = context.CompileDynamic("if(Date1 > #01/01/2009#, true, false)");

New Post: Is Variables needed for equations having DateTime?

tester27 — Wed, 08 Jul 2009 13:56:54 GMT

The error is raised at context.CompileDynamic and here is the error message:

ex.Message

"CompareElement: Operation 'GreaterThan' is not defined for types 'String' and 'String'"

ex.StackTrace

" at Ciloci.Flee.ExpressionElement.ThrowCompileException(String messageKey, CompileExceptionReason reason, Object[] arguments)\r\n at Ciloci.Flee.BinaryExpressionElement.ThrowOperandTypeMismatch(Object operation, Type leftType, Type rightType)\r\n at Ciloci.Flee.BinaryExpressionElement.ValidateInternal(Object op)\r\n at Ciloci.Flee.BinaryExpressionElement.Configure(ExpressionElement leftChild, ExpressionElement rightChild, Object op)\r\n at Ciloci.Flee.BinaryExpressionElement.CreateElement(IList childValues, Type elementType)\r\n at Ciloci.Flee.FleeExpressionAnalyzer.AddBinaryOp(Production node, Type elementType)\r\n at Ciloci.Flee.FleeExpressionAnalyzer.ExitCompareExpression(Production node)\r\n at Ciloci.Flee.ExpressionAnalyzer.Exit(Node node)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.Parser.ExitNode(Node node)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.R

untime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.Recur

siveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.Pars

eElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.Parse

Pattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(

ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, Productio

nPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\

r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r

\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseElement(Production node, ProductionPatternElement elem)\r\n at Cilo

ci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseAlternative(ProductionPatternAlternative alt)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParsePattern(ProductionPattern pattern)\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.RecursiveDescentParser.ParseStart()\r\n at Ciloci.Flee.PerCederberg.Grammatica.Runtime.Parser.Parse()\r\n at Ciloci.Flee.ExpressionContext.DoParse()\r\n at Ciloci.Flee.ExpressionContext.Parse(String expression, IServiceProvider services)\r\n at Ciloci.Flee.Expression`1.Compile(String expression, ExpressionOptions options)\r\n at Ciloci.Flee.Expression`1..ctor(String expression, ExpressionContext context, Boolean isGeneric)\r\n at Ciloci.Flee.ExpressionContext.CompileDynamic(String expression)\r\n at EquationEditorDemo.EquationEditor.buttonCalculate_Click(Object sender, EventArgs e) in C:\\EquationEditorDemo\\EquationEditorDemo\\EquationEditor.cs:line 151"

New Post: Is Variables needed for equations having DateTime?

eciloci — Tue, 07 Jul 2009 20:50:35 GMT

Can you post the error details?

New Post: Is Variables needed for equations having DateTime?

tester27 — Mon, 06 Jul 2009 15:37:13 GMT

Thanks for your reply.

I'm still getting errors if I use context object instead of engine:

ExpressionContext context = new ExpressionContext();
context.Imports.AddType(typeof(DateTime), "DateTime");

//context.Variables.Add("Date1", "DateTime.Parse(\"1/1/2010\")");
//context.Variables.Add("Date2", "DateTime.Parse(\"1/1/2009\")");

context.Variables.Add("Date1", "#1/1/2009#");
context.Variables.Add("Date2", "#1/1/2010#");

IDynamicExpression exp = context.CompileDynamic("if(Date1 > Date2,true,false)");
string value = exp.Evaluate().ToString();

New Post: Is Variables needed for equations having DateTime?

eciloci — Wed, 01 Jul 2009 23:16:10 GMT

Are you importing the DateTime type into your context?

The following code works:

CalculationEngine engine = new CalculationEngine();
ExpressionContext context = new ExpressionContext();
context.Imports.AddType(typeof(DateTime), "DateTime"); // Import the DateTime functions under the "DateTime" prefix
engine.Add("DateDiff1", "DateTime.Parse(\"1/1/2010\") - DateTime.Parse(\"1/1/2009\")", context);

object obj = engine.GetResult("DateDiff1");

The error message that you get if you don't import the DateTime type is not very helpful so I'll try to make it better.

However, FLEE supports DateTime literals, so you can write the following instead:

CalculationEngine engine = new CalculationEngine();
ExpressionContext context = new ExpressionContext();
engine.Add("DateDiff1", "#01/01/2010# - #01/01/2009#", context);

object obj = engine.GetResult("DateDiff1");

You can use the context.ParserOptions.DateTimeFormat to control the format string for DateTime literals. By default, it is set to the short date string for the current culture.

New Post: Is Variables needed for equations having DateTime?

tester27 — Wed, 01 Jul 2009 16:24:20 GMT

If I use directly DateTime objects in the equation, its throwing an error but if I create varaibles and use the variables in the equation then its working fine. Does it mean that variables are needed for the DateTime equations? if yes then whenever equations get updated then need to update the variables ??

Option 1:

engine.Add("DateDiff1", "DateTime.Parse(\"1/1/2010\") - DateTime.Parse(\"1/1/2009\")", context);

object obj = engine.GetResult("DateDiff1");

Option 2:

variables.Add("Date1", DateTime.Parse("1/1/2009"));

variables.Add("Date2", DateTime.Parse("1/1/2010"));

engine.Add("DateDiff2", "Date2-Date1", context);

obj = engine.GetResult("DateDiff2");

Thanks,

New Post: Abs

eciloci — Fri, 26 Jun 2009 17:19:35 GMT

You could use the IF operator to achieve the same thing:

if(num < 0, -num, num)

New Post: Validating Input

davojc — Fri, 26 Jun 2009 08:54:02 GMT

Great,

Let me know when this happens.

Thank

David

New Post: Abs

edblake — Thu, 25 Jun 2009 09:17:43 GMT

Hi I've looked around but I can't see a way of doing it. Is there any equivalent to an Abs function?

Thanks