Question

I am having trouble running FsLex from F# PowerPack 2.0.0.0 on Mac. When I simply run the program I see:

$ mono /Library/Frameworks/Mono.framework/Versions/3.0.2/lib/mono/FSharpPowerPack-2.0.0.0/bin/fslex.exe 

Unhandled Exception:
System.TypeLoadException: Could not load type
'.$FSharp.PowerPack.FsLex.Driver' from assembly 'fslex, Version=2.0.0.0,
Culture=neutral, PublicKeyToken=a19089b1c74d0809'.
[ERROR] FATAL UNHANDLED EXCEPTION: System.TypeLoadException: Could not load type
'.$FSharp.PowerPack.FsLex.Driver' from assembly 'fslex, Version=2.0.0.0,
Culture=neutral, PublicKeyToken=a19089b1c74d0809'.

The steps I followed were:

1. Install MDK 3.0.2.
2. Download F# PowerPack 2.0.0.0 released May 20, 2010. sudo gacutil -i on each DLL. sudo cp -r FSharpPowerPack-2.0.0.0 /Library/Frameworks/Mono.framework/Versions/3.0.2/lib/mono
3. Download the April 2011 CTP of F# 2.0.0.0 from http://www.microsoft.com/en-us/download/details.aspx?id=11100 and use the install-mono.sh script.

What does the error mean and how do I fix it?

Answer 1

You might try reposting your question to the fsharp-opensource mailing list. That’s where most of the collaboration around F# on Mono takes place, so you might have better luck getting an answer there.

A couple of quick suggestions to try first though:

• The April 2011 F# CTP is way out of date now. Try installing F# directly from the open source F# repository instead — it includes a number of installation fixes and minor patches that make the F# compiler (and F# interactive) work better on Mono.
• The PowerPack is also quite out of date at this point. Once you’ve built/installed F# from sources (above), you might try building the PowerPack from sources too to see if that fixes the problem for you.