Skip to content

Util.Table broken for anonymous records #233

@rudihorn

Description

@rudihorn

Description

This seems to more be an F# bug related to a unification error with F# anonymous record types (possibly a dotnet restriction?).

Repro steps

[ {|id=5; name = "hello"|} ] |> Util.Table

Expected behavior

Table output

Actual behavior

Error message:

Type constraint mismatch. The type
'{|id : int ; name : string|} list'
is not compatible with type
'seq<{|id : int ; name : string|}>'

Known workarounds

Define it within a module:

open System

module MUtil =
    let Row (columns:seq<Reflection.PropertyInfo>) (item:'A) =
        columns
        |> Seq.map (fun p -> p.GetValue(item))
        |> Seq.map Convert.ToString
        |> Seq.toArray

    let Table (items:seq<'A>, propertyNames:seq<string> option) =
        let properties = 
            if propertyNames.IsSome then
                typeof<'A>.GetProperties()
                |> Seq.filter (fun x -> (propertyNames.Value |> Seq.exists (fun y -> x.Name = y)))
                |> Seq.toArray
            else
                typeof<'A>.GetProperties()
        { 
            Columns = properties |> Array.map (fun x -> x.Name);
            Rows = 
                items 
                |> Seq.map (Test.MyRow properties)
                |> Seq.toArray
        }
    
    let DefaultTable items = Table (items, None)

Then call:

[ {|id=5; name = "hello"|} ] |>  MUtil.DefaultTable

Related information

  • Operating system: Ubuntu
  • Branch: Master
  • CoreCLR

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions