LoopExpression Example

C# Code :

Action<int> loopSample = cpt =>

            {

                for (int i = 0; i < cpt; i++)

                    Console.WriteLine(i);

            };

Expression Tree Code :

Expression<Action<int>> loopSampleE =

                // Action<int> loopSample =

                Expression.Lambda<Action<int>>(

                //{

                    Expression.Block(

                //i = 0

                        new[] { iVariable },

                        Expression.Assign(

                        iVariable,

                        Expression.Constant(0)),

                //while(true)

                        Expression.Loop(

                //{

                            Expression.Block(

                //if

                                Expression.IfThen(

                //!(i < cpt)

                                Expression.Not(

                                Expression.LessThan(iVariable, cptParam)),

                //break

                                Expression.Break(breakOuter)),

                //Console.WriteLine(i)

                                Expression.Call(typeof(Console).GetMethod("WriteLine", new Type[] { typeof(int) }), iVariable),

                //i++

                                Expression.PostIncrementAssign(iVariable)),

                        breakOuter)),

                cptParam);

Expression Tree Debug View :

.Lambda #Lambda1<System.Action`1[System.Int32]>(System.Int32 $cpt) {
    .Block(System.Int32 $i) {
        $i = 0;
        .Loop  {
            .Block() {
                .If (
                    !($i < $cpt)
                ) {
                    .Break #Label1 { }
                } .Else {
                    .Default(System.Void)
                };
                .Call System.Console.WriteLine($i);
                $i++
            }
        }
        .LabelTarget #Label1:
    }
}

IL Code :

//i = 0
IL_0000: ldc.i4.0

IL_0001: stloc.0
//i < cpt

IL_0002: ldloc.0

IL_0003: ldarg.1

IL_0004: clt

//Condition Valid : --> go to WriteLine Block

IL_0006: brtrue IL_0010
//Condition InValid--> ret

IL_000b: br IL_0021

//Console.WritleLine(i)

IL_0010: ldloc.0

IL_0011: call 6000003 System.Console.WriteLine(Int32)

//i++

IL_0016: ldloc.0

IL_0017: stloc.1

IL_0018: ldloc.1

IL_0019: ldc.i4.1

IL_001a: add

IL_001b: stloc.0

//loop

IL_001c: br IL_0002

IL_0021: ret