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Visual Studio Code – How to apply modifier to expression

I have an XML file, here is a snippet:

<response>
  <data offset="4" length="2" pattern="[%lx]" desc="Hours"/>
  <data offset="2" length="2" pattern="[%lx]" desc="Minutes"/>
  <data offset="0" length="2" pattern="[%lx]" desc="Seconds"/>
  <data offset="6" length="2" pattern="[%lx]" desc="Day"/>
  <data offset="8" length="2" pattern="[%lx]" desc="Month"/>
  <data offset="10" length="2" pattern="[%lx]" desc="Year" modifier="+2020"/>
</response>

This is used to decode a response in code which is the time and date, the year is returned in the response as 04, I want to apply the modifier to this value, I’m trying to keep it as flexible and generic as possible.

How can I take the value of the modifier which I have in code as a string and apply it to the value? My code:

double dblData = 0.0;
if (double.TryParse(strData, out dblData) == true) {
...
}

strData is a string which in this case contains 04, how can I apply the modifier which I have in another variable called strModifier to strData so it becomes 04+2020 and the result is 2024?

Can I do this with Lambda?

I am using Microsoft Visual Studio Professional 2022, version 17.11.3, the project is using the Target framework .NET Framework 4.8, Output type Windows Application.

I am having problems trying out the suggestions because I cannot add Microsoft.CodeAnalysis.CSharp.Scripting, I’ve also tried the other suggested answer but the code will not compile.

Tags:

3

Answers


  1. Chosen as BEST ANSWER
    0

    I found this post: Is there an eval function In C#?

    And based on the answer posted by rezo-megrelidze:

    if (cdmProvider == null) {
    cdmProvider = new CSharpCodeProvider();
}
if (cdmProvider != null) {
    string strModifier = detail.strModifier;
    strModifier = strModifier.Replace(mcstrValue, strData);
    CompilerResults results = cdmProvider.CompileAssemblyFromSource(
        new CompilerParameters()
      , new string[] {                                                                    
        string.Format(@"namespace nsILC {{
            public class clsILC {{
                public double Eval() {{
                    return {0};
                }}
            }}", strModifier)
        });
Assembly test = results.CompiledAssembly;
dynamic evalulator = Activator.CreateInstance(test.GetType("nsILC.clsILC"));
Console.WriteLine(evalulator.Eval());

    Works a treat, in the console I can see the correct result.


  2. 0 
    using Microsoft.CodeAnalysis.CSharp.Scripting;

class Program
{
    static async Task Main(string[] args)
    {
        string strData = "04";
        string strModifier = "+2020";

        int result = (int) await CSharpScript.EvaluateAsync(strData + strModifier);
    } 
}
    Login or Signup to reply.
  3. 0

    You could try this code. As I saw, the value of modifier could be also +,2020, so here’s generic approach to account also for that (explanations in code):

    static double Parse(string strData, string modifier)
{
    // Parse strData to number
    var @double = double.Parse(strData);
    // Extract operation to perform from first character.
    var operation = modifier[0];
    // Apply regex to capture all numbers:
    // it just captures consecutive digits
    // and parses to number.
    var numbers = Regex.Matches(modifier.Substring(1), @"d+")
        .Select(x => double.Parse(x.Value))
        .ToArray();
    // Apply operation based on extracted information.
    // Also, if you are sure there will be always one number,
    // you can use numbers[0] instead of numbers.Sum()
    return operation switch
    {
        '+' =>  @double + numbers.Sum(),
        //'-' =>  @double - numbers.Sum(),
        //'*' =>  @double * numbers.Sum(),
        _ => throw new NotSupportedException(),
    };
}

    Now it can be used as below. Both examples return 2024:

    var result1 = Parse("04", "+2020");
var result2 = Parse("04", "+,2020");
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