Hi I'm running on Xamarin 6.1.5 on MacOS
I've installed FSharp.Charting 0.90.14
its the first time I'm trying to use it
whether i try to compile or i try in F# interactive, i get this kind of error
(Chart.Line [ for x in 1.0 .. 100.0 -> (x, x ** 2.0) ]).ShowChart();;
System.ArgumentNullException: Value cannot be null. Parameter name:
key at System.ThrowHelper.ThrowArgumentNullException
(...)
EDIT1
I was very stupid indeed and did not install the Gtk version
EDIT2
the above one-liner code in F# interactive "works". It takes some unusual time to execute, but i see the window with the chart. It is not possible to hover on the chart and see coordinates, but maybe its not a default setting ?
also, i don't understand how to CLOSE the window where the chart appears.
Is everything alright ?
Aren't you trying to use FSharp.Charting package on Mac instead of FSharp.Charting.Gtk, as documentation says you to do?
See https://fslab.org/FSharp.Charting/ReferencingTheLibrary.html
Edit: answering to the edit of the original question: no, there should be no warnings. That's how it works for me:
$ fsharpi
F# Interactive for F# 4.1
Freely distributed under the Apache 2.0 Open Source License
For help type #help;;
> #load "packages/FSharp.Charting.Gtk.0.90.14/FSharp.Charting.Gtk.fsx" ;;
[Loading /Users/avysk/Projects/_Sandbox/testfsharpcharting/packages/FSharp.Charting.Gtk.0.90.14/FSharp.Charting.Gtk.fsx]
namespace FSI_0002.FSharp.Charting
val verifyMac : unit -> bool
val isMac : bool
module FsiAutoShow = begin
end
> open FSharp.Charting ;;
> (Chart.Line [ for x in 1.0 .. 100.0 -> (x, x ** 2.0) ]).ShowChart();;
Binding session to '/Users/avysk/Projects/_Sandbox/testfsharpcharting/packages/FSharp.Charting.Gtk.0.90.14/lib/net40/OxyPlot.dll'...
Binding session to '/Users/avysk/Projects/_Sandbox/testfsharpcharting/packages/FSharp.Charting.Gtk.0.90.14/lib/net40/OxyPlot.GtkSharp.dll'...
val it : unit = ()
(The window appears immediately.)
Related
I have installed the MathNet.Numerics package on Visual Studio 2017 using the Package Manager Console.
I have attempted to open a Source File on and execute an algorithm relating to the MersenneTwister type within the MathNet namespace.
However, when I try to generate numbers using this algorithm in F# Interactive, I am met with the error:
File1.fs(3,6): error FS0039: The namespace or module 'MathNet' is not defined. Maybe you want one of the following:
Math
Code is as per below:
module File1
open MathNet.Numerics.Random
let mersenneTwister = new MersenneTwister(42)
let a = mersenneTwister.NextDouble()
Apologies if this is unclear, I am relatively new to F# :)
Are you per change using the interactive window or running an fsx script? Cause these don't recognize your packages.
When reproducing your problem in a F# console app I got this output: Hello 0.374540.
I installed the MathNet.Numerics.fsharp nuget package (which also uses the package you mention) and used the following code in the Program.fs:
open MathNet.Numerics.Random
let hello () =
let mersenneTwister = new MersenneTwister(42)
let a = mersenneTwister.NextDouble()
printfn "Hello %f" a
[<EntryPoint>]
let main argv =
hello ()
0 // return an integer exit code
If you do want to use the nuget package from a script you can reference it in the top of your script like so (absolute or relative)
#r #"C:\Path\bin\Debug\netcoreapp3.0\MathNet.Numerics.dll"
I am trying to read a GIF file header into a structure with F#, using Mono 5.8 on Mac OSX. The following code sample works fine in Visual Studio 2017 on Windows 10; however, when I try to run it in Visual Studio for Mac, I get the following error in F# interactive:
* Assertion at class-accessors.c:138, condition `mono_class_has_static_metadata (klass)' not met
The code I am using is below. The structure is probably incorrect since I just threw it together quickly for the question, but
open System
open System.IO
open System.Runtime.InteropServices
[<Struct; StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)>]
type GifHeader = {
[<MarshalAs(UnmanagedType.ByValTStr, SizeConst = 3)>]
signature: string
[<MarshalAs(UnmanagedType.ByValTStr, SizeConst = 3)>]
version: string
logicalWidth: int16
logicalHeight: int16
}
When I invoke Marshal.SizeOf(typeof<GifHeader>) in Visual Studio for Mac's FSI, I get the error mentioned above.
I noticed that when I am reading into a structure like:
[<Struct; StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)>]
type SomeOtherHeader = {
field1: uint16
field2: int32
field3: int16
field4: float
}
i.e. with no MarshalAs UnmanagedType specification, the error is not thrown.
Does anyone know what this error means? I haven't seen any other instances of this particular error on Google or other SE posts, and it is especially puzzling since it doesn't occur on Windows/.NET Framework 4.7. Not having the interactive window to test code is a massive hindrance for learning, and quite frustrating since I don't think it's possible to use an alternative (non-Mono) FSI.
This was an issue intrinsic to the current Mono release. Per the Mono team, this has been fixed as of Mono 5.14.
I'm trying to use FAKE to build my F# project.
The build.fsx looks like below and works fine.
#r "packages/FAKE/tools/FakeLib.dll"
open Fake
Target "Default" (fun _ ->
trace "Hello World from FAKE"
)
RunTargetOrDefault "Default"
Then I want to use fsc from FAKE. Following the official tutorial, I added one line open Fake.FscHelper and get below error message:
#r "packages/FAKE/tools/FakeLib.dll"
open Fake
open Fake.FscHelper
// this value is not a function and can not be applied
// union case FscParam.Target: TargetType -> FscParam
Target "Default" (fun _ ->
~~~~~~~~~~~~~~~~
trace "Hello World from FAKE"
)
RunTargetOrDefault "Default"
I appreciate if anyone can give me any advice.
I'm using VS Code on Mac with Mono 4.2.1.
And my paket.lock looks like below:
NUGET
remote: https://www.nuget.org/api/v2
specs:
FAKE (4.21.0)
FSharp.Core (4.0.0.1)
FsUnit (2.0.0)
FSharp.Core (>= 3.1.2.5)
NUnit (3.0.1)
NUnit (3.0.1)
This happens because the module FscHelper defines a constructor called Target (see source), and that constructor conflicts with the Target function from the TargetHelper module. There is an issue filed about it.
Until the issue is fixed, there are three ways to work around this ambiguity:
Don't open FscHelper, just use all its innards in a qualified manner (e.g. FscHelper.Compile etc.)
Re-alias the TargetHelper.Target function in the local scope:
open Fake
open Fake.FscHelper
let Target = TargetHelper.Target
Target "Default" (fun _ ->
trace "Hello World from FAKE"
)
Reorder the open statements:
open Fake.FscHelper
open Fake
And since you're using this helper, note that the documentation for it is outdated. In particular, the Fsc task is deprecated in favor of the Compile task (see source).
Change the order of the open statements
#r #"packages/FAKE/tools/FakeLib.dll"
open Fake.FscHelper
open Fake
Target "a" (fun _ ->
["a.fs"] |> Compile []
The order of your open statements determines the precedence of the name resolution with the later opened modules and namespaces taking precedent.
I have 2 files: Asm.fs, AsmTest.fs
Asm.fs
namespace Assembler
[<Measure>] type ln
[<Measure>] type col
[<Measure>] type port
type Addr = int<ln> * int<col> * int<port>
module Asm =
let emptyAddr : Addr = (-1<ln>, -1<col>, -1<port>)
AsmTest.fs
module Assembler.Tests
[<Test>]
let someTest() =
let x = Asm.emptyAddr
When I debug someTest() code, I get that x = null, what am I doing wrong?
P.S. files in the different projects visual studio projects. Asm.fs in the Assembler project and AsmTest.fs in the AssemblerTest project.
I found an interesting behavior. My problem will be resolved, if I add some file (even empty) to the Assembler project. Can anyone explain this behavior?
The debugger sometimes has issues showing the correct values. For me however, having exactly the same Asm.fs and AsmTest.fs like this:
module Assembler.Tests
open NUnit.Framework
[<Test>]
let someTest() =
let x = Asm.emptyAddr
Assert.IsNotNull x
the test passes and if I set a breakpoint at the assertion, x is correctly shown as {(-1, -1, -1)}
As the code that you show does not compile as it is (Block following this let is unfinished. in someTest), could you try my test above and/or show your complete test method?
Using your code I can reproduce the behaviour. If I set my projects to console applications, my test will fail as well. So, it seems that for console projects, not having any other file or an [<EntryPoint>] surprisingly skips the initialization of module values. For me, the compiler at least issues a warning Main module of program is empty where I use x in the test. The solution to the problem is therefore:
make sure you treat warnings as errors
have an [<EntryPoint>] for console applications
use library projects for libraries
I am getting this when trying to parse a simple csv string. I am running F# out of VS 2013, the dll says it is version 4.3.0.1 which I thought was F# 3.1. My Fsharp.Data dll is 1.1.10.
I am trying to run this as part of an nunit test using resharper. The snippet does work in interactive mode.
Here is the code:
open FSharp.Data
type TestCsv = CsvProvider<"test,taht\n1,1">
let x = TestCsv.Parse "test,taht\n1,1"
let tests = x.Data |> Seq.map (fun x -> x.test)
tests |> Seq.head
And the result:
System.Exception : Couldn't parse row 1 according to schema: Method not found: 'Microsoft.FSharp.Core.FSharpOption`1<System.String> FSharp.Data.RuntimeImplementation.Operations.AsOption(System.String)'.
Any ideas how to fix this?
FSharp.Data 1.1.10 doesn't support F# 3.1/VS2013. Please try with the prerelease version 2.0.0-alpha3 and let us if that works. Make sure both the unit test project and the library project are using the same version of FSharp.Core (either 4.3.0.0 or 4.3.1.0)