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Util.Table broken for anonymous records #233
Description
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.TableExpected 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.DefaultTableRelated information
- Operating system: Ubuntu
- Branch: Master
- CoreCLR
Activity
rudihorn commentedon Jun 28, 2019
Questions I still have:
cgravill commentedon Jun 28, 2019
It's not a .NET Core issue.
I'd be tempted to just initialise as a seq or convert to that:
but improving compatibility seems like a good idea too.
cgravill commentedon Jun 28, 2019
To confirm the implicit conversion works for explict records:
IfSharp/src/IfSharp.Kernel/Util.fs
Lines 86 to 100 in 5a415a7
rudihorn commentedon Jun 28, 2019
Yes this is what was confusing me about this. The conversion to a seq first works for me though.