Hi All,
I have the following little class of iterators that allow me to iterate over
elements in the file system. I have nested some of them, and then added Func<FileInfo,
bool> delegates to filter out unwanted files. I get an InvalidProgramException
and haven't (yet) been able to find out what's going on. Do you have any
ideas?

TIA

Andrew Matthews
========================================

   public class FsIter
   {
       public static IEnumerable<DirectoryInfo> SubDirectories(DirectoryInfo
di)
       {
           yield return di;
           foreach (DirectoryInfo directory in di.GetDirectories())
           {
               foreach (DirectoryInfo subDirectory in SubDirectories(directory))
               {
                   yield return subDirectory;
               }
           }
       }

       public static IEnumerable<FileInfo> AllFilesUnder(DirectoryInfo d)
       {
           foreach (DirectoryInfo dir in SubDirectories(d))
           {
               foreach (FileInfo fileInfo in dir.GetFiles())
               {
                   yield return fileInfo;
               }
           }
       }

       public static IEnumerable<FileInfo> MatchingFilesUnder(Func<FileInfo,
bool> x, DirectoryInfo d)
       {
           foreach (FileInfo fileInfo in AllFilesUnder(d))
           {
               if (x(fileInfo))
                   yield return fileInfo;
           }
       }

       public static IEnumerable<FileInfo> FilesByExtension(string ext,
DirectoryInfo d)
       {
           Func<FileInfo, bool> test = x=>x.Extension==ext;
           return Match(test, AllFilesUnder(d));
       }
       
       public static IEnumerable<IT> Match<IT>(Func<IT, bool> test, IEnumerable<IT>
col)
       {
           foreach (IT it in col)
           {
               if(test(it))
                   yield return (it);
           }
       }
   }

I tried to exercise it with the following:

       [Test]public void TestIterateTestDir2()
       {
           string testdir = @"C:\etc\dev\fstags\src\UnitTests\tests";
           List<FileInfo> files = new List<FileInfo>(FsTags.Core.FsIter.FilesByExtension(".txt",
new DirectoryInfo(testdir)));
           Assert.AreEqual(files.Count, 4);
       }

And I got the following:

System.InvalidProgramException: Common Language Runtime detected an invalid
program.
at FsTags.Core.FsIter.FilesByExtension(String ext, DirectoryInfo d)
at fstags.UnitTests.TestFsIter.TestIterateTestDir2() in TestFsIter.cs:line
26

I am running C# 3.0 May CTP (LINQ preview) and ReSharper 2.0 (2005)