Using KeyNotFoundException and exception patterns

• Category: Exceptions
• Description: Raising a 'KeyNotFoundException' exception, and using exception patterns
• Code:

using Nemerle;
using System;
using System.Console;
using System.IO;
using System.Collections.Generic;

    try 
    {
        WriteLine("About to raise an exception...");
        match (DateTime.Now.DayOfWeek)
        {
         | DayOfWeek.Monday => throw KeyNotFoundException() 
         | _                => assert(false, "it's not Monday")
        }
    }
    catch
    {
        | _ is KeyNotFoundException => WriteLine("Caught a 'KeyNotFoundException' exception, it must be Monday")
        | x is AssertionException   => WriteLine($"Caught a 'AssertionException' exception: $x")
    }

• Execution Result (in case of Monday):

About to raise an exception...
Caught a 'KeyNotFoundException' exception, it must be Monday

• Execution Result (in other cases):

About to raise an exception...
Caught a 'AssertionException' exception: Nemerle.Core.AssertionException: assertion failed in file C:\Users\Alexander\AppData\Local\Temp\tmp373B.tmp, line 13: it's not Monday
   в tmp373B.Main()

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