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If a satisfyUserState parser returns None but also the user state predicate returns false, then the None should be ignored and the state should backtrack. Right now, anything other than a Some will fail and not backtrack which causes instability in other parsers since the stream position has been modified.

It'd be nice to see some benchmarks to show the advantage of parsecclone over alternatives

BenchmarkDotNet is really easy to use and generates preformatted charts that you can paste straight into the readme.

   System.ArgumentOutOfRangeException : Index and length must refer to a location within the string.
Parameter name: length
  at System.String.Substring (System.Int32 startIndex, System.Int32 length) [0x0006a] in <a07d6bf484a54da2861691df910339b1>:0 
  at FooStringUnitTests.testFloat () [0x00047] in <5968faeedd987869a7450383eefa6859>:0 
  at (wrapper managed-to-native) System.Reflection.MonoMethod:InternalInvoke (System.Reflection.MonoMethod,object,object[],System.Exception&)
  at System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00032] in <a07d6bf484a54da2861691df910339b1>:0 

https://travis-ci.org/devshorts/ParsecClone/builds/253690729

@jinahong can you take a look and see if this is related? This will prevent cutting a new release

Now that the blit emit code is all in f# we don't need to have a c# library dependency.

We need to remove the project, update the msbuild, the nuspec, and the readme.

Hi,

I am trying rewrite my hand-made binary parser with ParserClone and can not figure out how can I seek from begin of stream? For example, suppose there is 64 byte-length file and I need to begin to parse offset which locates at end of file (last 4 bytes). Then I need to seek from begin of file by this parsed offset and parse another int32.

Create test file:

let writeTestFile () =
    use f = IO.File.OpenWrite("testfile.bin")
    use bw = new IO.BinaryWriter(f)

    let value = 55
    let offset = 32

    do bw.BaseStream.Seek(int64 offset, IO.SeekOrigin.Begin) |> ignore
    do bw.Write(BitConverter.GetBytes(value))

    do bw.BaseStream.Seek(int64 60, IO.SeekOrigin.Begin) |> ignore
    do bw.Write(BitConverter.GetBytes(offset))

Parse:

let parseTestFile () =
    let parser =
        bp.skip 60
        >>. bp.int32  // parse offset
        // ??? seek from start by readed offset
        >>. bp.int32 // parse value

    let fs = IO.File.OpenRead("testfile.bin")
    let bs = makeBinStream fs

    parser bs |> printfn "%A"

How can I do that?

The stream position should return the actual stream position, and not the cached start position that was used when the stream container was instantiated.

If a satisfyUserState parser returns None but also the user state predicate returns false, then the None should be ignored and the state should backtrack. Right now, anything other than a Some will fail and not backtrack which causes instability in other parsers since the stream position has been modified.

you know the drill