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fsi + exceptions
f#

Hi,

Is there a way to make fsi print line numbers when it reports exceptions (from files provided on the command line - specifically I use fsi with --exec a lot)? -g generally does the job with fsc.

Also, is there a way to detect from a .fs file is you are runing under fsi or fsc? This is for using portable command line processing between the environments - I currently use "--define FSI" to switch between fsi.CommandLineArgs and Sys.argv, but I was wondering if there was something similar already in existance.

Cheers,

Andy

.

Hi Andy,

We have a long-standing todo to emit debug symbols from FSI. This is why line numbers are not being shown. It also enable other interesting scenarios like launching the VS debugger at exceptions within generated code.

For the second point you want the prefedined --defines COMPILED and INTERACTIVE.

Regards

don

By on 6/7/2007 4:40 PM ()

I tried generating an exception from fsharpi while running with --debug:full and receive no line numbers.

May I presume that, seven years later, this long-standing todo is still long-standing?

By on 7/28/2014 7:43 AM ()

F# Interactive emits debug symbols.

(a) To get line information in exceptions, you have to be loading from a file, like "fsi foo.fsx" or a #load, or else #line directives must be emitted by the script or tool hosting F# Interactive. The #line directives are inserted autoatically by Visual Studio and Xamarin Studio.

(b) Line information seem to be missing for exceptions from top-level initialization code.

(c) inlining and optimization may affect the accuracy of line information

Example:

#line 3 @"abc.fs"

let f() =
printfn "hello"
printfn "hello"
printfn "hello"
printfn "hello"
printfn "hello"
(failwith "x" : int)

f()

System.Exception: x
at FSI_0004.f() in C:\test\abc.fs:line 9
at <StartupCode$FSI_0004>.$FSI_0004.main@()

Note the "line 9" on the second last line

By on 7/28/2014 8:16 AM ()

Thanks Don.

I've been making more and more use of fsi - it's such a cool tool. Debug info - at least for command line files (not sure how it would work for manually entered code to be honest) would be great.

Re. second point - I figured you'd already have something like this. Thanks for the head's up.

Cheers,

Andy

By on 6/9/2007 4:59 PM ()

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