17,085 questions
0
votes
1
answer
50
views
FS0072 (Lookup of object of indeterminate type... A type annotation may be needed) on "_.member"
type WeatherTool (factory: IHttpClientFactory) =
[...]
member private _.ProcessResponse<'T> (response:HttpResponseMessage) : Task<Result<'T, string>> = task {
[...]
...
- 3,370
1
vote
1
answer
60
views
Why are .fsx scripts executed when a compiled program is started?
I just noticed unexpected behavior in a newly created F# project.
I have a Development.fsx file that is listed in a <Compile> tag within the .fsproj file so that it is displayed nicely in the ...
- 199
1
vote
2
answers
72
views
Exception when loading F# types that implement an interface which uses generics from an assembly
I'm trying to load a type from an assembly at runtime that implements this interface which is in a project called PluginBase:
type IPlugin =
abstract member TestString: Option<string> with ...
- 21
Advice
0
votes
6
replies
55
views
Map Over Elements of a List with Successive Elements from Another List
I have two lists (both lists of lists of ints), and want to do the following:
(1) Take the first element of List 1 and use it as input to a function, then use List.map to map that function over all ...
- 13
1
vote
1
answer
94
views
Is there an equivalent to F# Async.StartAsTask that returns Async<'T> and lets you pass in a cancellation token?
Inside an async computation expression, I would like to be able to pass in a CancellationToken that cancels the child computation only (a.k.a. not the "ambient" token). I'm a little ...
- 1,256
0
votes
2
answers
122
views
translation of f# expression to c# in the debugger
Ionide debugger doesn't support f# now. Such expressions should be translated to c#.
How can I see, say, the following expression:
connections|>List.map(fun c->c.Probabilities)
Edits:
Tried the ...
- 6,659
2
votes
1
answer
96
views
Instantiation of type with recursive type constraints
The Announcing F #7 page gives the example code
type IAddition<'T when 'T :> IAddition<'T>> =
static abstract op_Addition: 'T * 'T -> 'T
type Number<'T when IAddition<'T&...
- 400
0
votes
1
answer
65
views
F# * and -> difference
I am struggling a little bit with understanding when a*b and a->b is cast (not sure if casting is good word) implicitly. Example: (I am not sure if this is feature or bug)
type a = {
x: int
}
...
- 41
Advice
2
votes
6
replies
114
views
How to model a deep inheritance in F# and allow all items to be added to an inventory
Referring to the attached diagram for an example hierarchy of materials, how can I represent this in F#? Once represented I need to be able to add ANY/ALL of the materials in level 4 (L4) of the ...
- 2,137
Best practices
2
votes
6
replies
132
views
Short circuit F# fold
Is there a convenient way to short circuit a Seq.fold evaluation?
For example, the following function evaluates if parenthesis are balanced in a string.
let isBalanced str =
(([], str) ||> Seq....
- 2,633
0
votes
0
answers
144
views
Visual Studio 2026 - F# MAUI fails with "DEP1700: The recipe file ..." is missing
I recently installed Visual Studio 2026.
My program is written in F# with MAUI.
With Visual Studio 2022 it was working so far, since I installed VS 2026, it fails on VS 2022 as well. Prior VS 2026 I ...
- 3,042
Best practices
0
votes
6
replies
93
views
Avoiding redundancy using type constraints in F#
I have a Measurement type and a Constant type, like so
type Measurement =
private
{ value: Var
uncertainty: float
unit: Unit }
static let getUncertainty v =
...
0
votes
1
answer
78
views
Defining exponentiation for a custom type
I have a simple record type with float fields that I'm trying to define the exponentiation for, but I keep running into errors one after another.
This was my first attempt:
static member ( ** )(a, ...
3
votes
1
answer
77
views
How does F# record label inference work across projects?
I have an F# solution with the following project structure:
ProjectA
Foo.fs
Bar.Fs
ClientA.fs
ProjectB
ClientB.fs
Where ProjectB depends on ProjectA.
Foo.fs defines a type:
type Foo =
{
...
- 17.4k
0
votes
1
answer
66
views
How to add Math text to XPlot.Plotly Plots in F#?
I want to add LaTeX to my plot. I'm using XPlot.Plotly to make plots.
let layout =
Layout(
title = "Plot of $\\frac{1}{t}$ vs h",
xaxis = Xaxis(title = "...
