Fast Lightweight Expression Evaluator

Closed Feature: Support for null value [945]

ECiloci — Thu, 16 May 2013 11:24:10 GMT

There needs to be support for specifying the null value in expressions

Closed Task: Strongly signed assemblies [2160]

ECiloci — Thu, 16 May 2013 11:24:09 GMT

Hi,

Great library, too bad the assemblies are not strongly signed. This prevents referencing the library from assemblies which have a strong key.
Any chances of providing strongly signed versions of assemblies? I tried to add the strong key to the source, but it couldn't be compiled since the gramatica DLL is also not strongly signed, and there is no source code for it.

Best regards,
Igor

Closed Issue: Owner base type property calling produce runtime error [3107]

ECiloci — Thu, 16 May 2013 11:24:08 GMT

I have specified the Owner property for the expression object, and the type of owner object has base type which is not Object. When I get the value of base type property, an runtime exception occurred. My related code is (C#):
public abstract class Constraint
{
private string name = "";
public string Name
{
get { return name; }
set { name = value; }
}
}

public class PrimaryKey : Constraint
{
}

Template calculate code is:
ExpressionContext expressionContext = new ExpressionContext();
expressionContext.Options.StringComparison = StringComparison.InvariantCultureIgnoreCase;
bool brs = ExpressionFactory.CreateGeneric<bool>("Name<>null", new PrimaryKey(), expressionContext).Evaluate();

When I was debugging into method ExpressionOptions.IsOwnerType(ByVal t As Type), I found that the value of Me.OwnerType is Constraint and t is PrimaryKey. So the IL code Ldarg_0 cannot be generated. And then I modified this method body to Return t.IsAssignableFrom(Me.OwnerType), It works well.

Closed Issue: Implement standard constructors on all custom exceptions [3823]

ECiloci — Thu, 16 May 2013 11:24:07 GMT

Thanks for adding the [Serializable] attribute to custom exceptions, but we didn't quite make it deserializable yet. Please implement the 4 standard constructors on all custom exceptions:

public InvalidExpressionException()
{
}

public InvalidExpressionException(string s)
: base( s )
{
}

protected InvalidExpressionException(SerializationInfo info, StreamingContext context)
: base( info, context )
{
}

public InvalidExpressionException(string message, Exception innerException)
: base( message, innerException )
{
}

Thanks!
~Steve

Closed Feature: Indexer with more than one argument gives parser exception [7013]

ECiloci — Thu, 16 May 2013 11:24:06 GMT

Calling an indexer with more than one argument gives a parse exception on the list separator.

Unit tests:

[TestMethod]
public void TestIndexerWithOneArgument() {
ExpressionContext context = new ExpressionContext(new IndexerContainer());
IGenericExpression<string> expr = ExpressionFactory.CreateGeneric<string>("Indexer[\"Bob\"]", context);
Assert.AreEqual("name : Bob, selected : False", expr.Evaluate());
}

[TestMethod]
public void TestIndexerWithTwoArguments() {
ExpressionContext context = new ExpressionContext(new IndexerContainer());
IGenericExpression<string> expr = ExpressionFactory.CreateGeneric<string>("Indexer[\"Bob\"; true]", context);
Assert.AreEqual("name : Bob, selected : True", expr.Evaluate());
}

public class IndexerContainer {
public IndexerClass Indexer = new IndexerClass();
}
public class IndexerClass {
public string this[string name] {
get {
return this[name, false];
}
}
public string this[string name, bool isSelected] {
get {
return string.Format("name : {0}, selected : {1}", name, isSelected);
}
}
}

The first test succeeds, the second fails. I think it should succeed.

Can you have a look at the issue? Thanks!

BTW: I'm running these tests with a Dutch current culture, so I used ';' as list separator.

Closed Issue: Implicit castor is not used in FLEE expression [7048]

leithfx — Thu, 16 May 2013 11:24:06 GMT

I have implemented an implicit conversion to a double in a class (DoubleWrapper) that is used as a variable. When I use this class in C#, it works as expected:
double dResult = Math.Cos( aDouble );
However the same expression does not work in FLEE.
IDynamicExpression expression = context.CompileDynamic( "Math.Cos( aDouble )" );
It throws an exception indicating it cannot find Cos(DoubleWrapper)

It seems to me that FLEE should behave the same as C#. Perhaps when it does not find the initial method signature, try to find the first method with a signature that can be used via implicit conversion of the parameter.

The attached file contains example code to better explain the problem.

New Post: Is there a way to check whether the expression is valid before evaluating it?

ESSB — Wed, 27 Mar 2013 01:42:08 GMT

Hi,

New here, so hi.

Excellent project.

Got it working in MVC3, .NET4. C# environment to test rules against class objects. Looks good.
However I have found an issue, and that is I need to validate the expression to check it can compile before evaluating it, otherwise I will get a runtime exception. which crashes the application. I do not mind a graceful failure. Perhaps just wrapping the "evaluate" in a try catch block is enough. However is there a better method to do this, perhaps there is a method in FLEE.

Many thanks,

Ed

New Post: Library customization with payment.

neo2_e_van — Fri, 04 Jan 2013 04:47:10 GMT

Any one in this discussion forum can do support for this library project? My company can make a payment for some one that make customize the feature on the source code to fit with our main project. If some one interesting , please response on this discussion first. We need discusstion for furthur process.

New Post: Support Nullable type?

MiRos — Thu, 03 Jan 2013 13:43:18 GMT

The solution posted by spboyer doesn't seem to be working correctly for System.DateTime? (nullable System.DateTime).

Created Issue: No result for power higher than "30"! [15877]

IWIH — Sat, 22 Dec 2012 10:13:33 GMT

Hi,

Thank you for this fabulous library... The most thing I love about, is the ability to add a custom functions easily.

Please, check the error (mentioned in the title)... Anyone knows where I can find the operator "^" implementation in the library source, please, tell me.... I may be able to fix it.

Best regards.

New Comment on "LanguageReference"

aph31 — Fri, 21 Dec 2012 08:58:28 GMT

Hi, is there possible for me to write a multiline expression? Example: This is vb format If a > 0 then If a <= 1 then X = b * ( a * 1.5 ) else X = ( 1.5 + ( a - 1 ) * 2 ) * b end if else X = 0 End if If y = 1 then X = X * 2 End if How to write this into expression without using custom function. because i write the formula in texbox, and it is impossible for me to write them to custom function.

New Post: Some enhancements, please

TuRRiCAN — Mon, 17 Dec 2012 12:35:41 GMT

Hello, thanks for this great Evaluator.

I'm still at the beginning of understanding the wide spectrum of possibilities of this Evaluator.

I started use it in an Excel-like application. For this I took the CalculationEngine. Could you please add something like an update-function, please?

At first I push all the expressions via the batchloader. But if the content of one of my cells is changing (e.g. from y + 5 to r * 3), I want to update the engine. The only way I see at the moment is to .Remove("x") and .Add("x","r * 3"). For this I wish for a .Update("x", "r * 3") function.

Or missed I something?

Furthermore, is there a way to BatchAdd? Because BatchLoad clears the CalcEngine.

The last wish (for now) is a .Count function for the Batchloader, so I could count the entries (i added dynamic before)

Thanks a lot in advance

TuRRiCAN

New Post: iOS Support

GarethHayter — Mon, 10 Dec 2012 21:14:38 GMT

Thanks very much potpockey.

New Post: iOS Support

potpockey — Fri, 07 Dec 2012 08:04:57 GMT

Hi Gareth.

From what i know, Code Generation is not allowed by the iOS kernel, because of that MonoTouch doesn't include/support the Reflection.Emit namespace of .NET that flee heavily relies on.

http://docs.xamarin.com/ios/about/limitations - see the "No Dynamic Code Generation" section.

Flee will not work.

New Post: iOS Support

GarethHayter — Thu, 06 Dec 2012 23:35:47 GMT

Hi. Is FLEE able to run on iOS (via MonoTouch)?

Thanks, Gareth.

New Post: C# port

potpockey — Thu, 06 Dec 2012 12:44:09 GMT

Done :)

New Post: C# port

Aricie — Wed, 05 Dec 2012 11:42:16 GMT

Thanks a lot for that,

We're definitely up for contributing.

Can you add this account as a developper to the project?

See you there,

Jesse

CTO Aricie

New Post: C# port

potpockey — Sun, 02 Dec 2012 08:47:57 GMT

Hi guy's. I have ported Flee to C#.

Updated grammatica from 1.5 alpha to 1.5 stable and modified it to work well with Flee.

I have ran all of the unit tests and they all pass

I have compared benchmark results from original flee to Flee# and Flee# parses expressions faster - most probably the grammatica update.

The project is in codeplex - http://fleesharp.codeplex.com/

New Post: CompileGeneric throws error on parsing double quotes "

MrException — Tue, 30 Oct 2012 10:11:23 GMT

Hi,

When I try this code I getting an exception. I am trying to insert " (double quotes) within a string.

This is the code:

ExpressionContext fleeContext;

fleeContext = GetFleeContext<string>();

fleeContext.CompileGeneric<string>("\"");

this throws an exception which reads: Unexpected character: Unexpected character: \" Line: 1, Column: 1

Any idea how can acheive this? i.e. being able to parse " successfully by flee

Regards,

New Post: C# port

SidAhmedDev — Mon, 29 Oct 2012 08:44:38 GMT

chadknudson wrote:

I have managed to port FLEE to C# -- I call it FleeSharp :-) I haven't been able to find a way to get in touch with the original author Ciloci to get his blessing on it, but it was a relatively painless process to get it up and running in C#.

Hi, as Aricie said, it's good news, personaly, it will help me a lot to have the C# version. Did you publish it somwhere ?

Thanks