Hover.fs

/// <summary>
/// The hover capability shows a tooltip when you hover over something of interest.
/// </summary>
/// <see href="https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_hover"/>
module LspExample.Hover

open Ionide.LanguageServerProtocol.Types
open LspExample.Types
open LspExample.Types.DemoLang

/// <summary>
/// Generate hover information: the type of the value and some information about it
/// </summary>
/// <param name="hoverLocation">Where the hover is requested</param>
/// <param name="contents">The parsed file to lookup within</param>
let LookupHover (hoverLocation: Position) (contents: Line[]) : Hover =
    match contents |> Array.tryItem (int hoverLocation.Line) with
    | Some { Value = Number number
             Contents = contents
             Line = line } ->
        { Contents =
            U3.C1
                { MarkupContent.Kind = MarkupKind.PlainText
                  Value = $"(Number) {number}" }
          Range = range (line, 0) (line, contents.Length) |> Some }
    | Some { Value = Text text
             Contents = contents
             Line = line } ->
        let leading = text.TrimStart()
        let trailing = text.TrimEnd()

        { Contents =
            U3.C1
                { MarkupContent.Kind = MarkupKind.PlainText
                  Value = $"(Text) Length={text.Trim().Length}" }
          Range = range (line, contents.Length - leading.Length) (line, trailing.Length) |> Some }
    | _ ->
        { Contents =
            U3.C1
                { MarkupContent.Kind = MarkupKind.PlainText
                  Value = "No hover information to display here" }
          Range = None }