What tools are available for F# debugging?

Question

• Are there gdb (or similar) for F#?
• What tools/programs do F# programmers normally use for tracing F# code in Mono?
• Does Visual Studio 2010 provides some integrated debugging tools for F#?

Answer 1

Any .NET debugger should work on F# code. The Visual Studio debugging experience is basically the same as for any other language (e.g. you can set breakpoints in the editor, etc.). I can't speak to what tools people use on Mono.

Answer 2

Visual Studio 2010 provides a fantastic debugging experience for F#, including breakpoints, tracepoints, call stacks, locals, stepping, set next statement, threads window, poking new values into variables, debugger visualizers, conditional breakpoints, immediate window, ... the only caveat is that the last two use the C# expression evaluator (F# does not have its own debugger EE), which means you must type e.g. C# syntax into the 'immediate window'.

(Everything I mentioned above is available for free if you download the free VS2010 Integrated Shell and the F# CTP.)

I am not sure what is available right now for Mono, but would not be surprised if there is something decent already, and something even better coming in the not-too-distant future.

Answer 3

Mono has its own debugger [0]. The debugging format situation is slightly confusing because Visual Studio will generate pdb files which are needed for their debugger. Mono uses the alternative mdb format. fsc.exe (The f# compiler) will generate the appropriate ones for whichever platform it is run on.

The Monodevelop IDE can be used for general debugging of .net assemblies, even though it doesn't support a released f# version yet. You'll need to refer to your project's generated assemblies in the project.

Note that you also have to pass '--debug' to mono if you're executing it on the command line and want, for example, file names and line numbers in stack traces.

[0] http://www.mono-project.com/Debugger