wip: hover support

packages/darklang/keywordDesc.dark

@@ -0,0 +1,57 @@
+module Darklang =
+  module KeywordDescription =
+    type KeywordDescription = { name: String; description: String }
+
+    let keywords () : List<KeywordDescription> =
+      [ KeywordDescription
+          { name = "module"
+            description =
+              "Used to associate a name with a group of related types, values, and functions, to logically separate it from other code." }
+        KeywordDescription
+          { name = "const"
+            description = "Keyword to specify a constant literal." }
+        KeywordDescription
+          { name = "let"
+            description =
+              "Lets creates a name with an immutable value, and a scope in which that is defined." }
+        KeywordDescription
+          { name = "type"
+            description = "Used to declare an alias, record, or an enumeration type." }
+        KeywordDescription
+          { name = "of"
+            description = "of keyword description TODO" }
+        KeywordDescription
+          { name = "with"
+            description = "with keyword description TODO" }
+        KeywordDescription
+          { name = "if"
+            description = "Used in conditional expressions." }
+        KeywordDescription
+          { name = "then"
+            description = "then keyword description TODO" }
+        KeywordDescription
+          { name = "else"
+            description = "else keyword description TODO" }
+        KeywordDescription
+          { name = "fun"
+            description = "fun keyword description TODO" }
+        KeywordDescription
+          { name = "match"
+            description = "match keyword description TODO" }
+        KeywordDescription
+          { name = "when"
+            description = "when keyword description TODO" }
+        KeywordDescription
+          { name = "List"
+            description = "List keyword description TODO" }
+        KeywordDescription
+          { name = "Dict"
+            description = "Dict keyword description TODO" }
+        KeywordDescription
+          { name = "DB"
+            description = "Db keyword description TODO" } ]
+
+    let getKeywordDescription (name: String) : Stdlib.Option.Option<String> =
+      (keywords ())
+      |> Stdlib.List.findFirst (fun k -> k.name == name)
+      |> Stdlib.Option.map (fun k -> k.description)

packages/darklang/languageTools/lsp-server/hover.dark

@@ -10,14 +10,74 @@ module Darklang =
           //get position
           let position = params.position
 
-          //TODO: get hover information
+          /// Find the document in scope
+          let doc =
+            state.documentsInScope
+            |> Stdlib.Dict.get params.textDocument.uri
+            |> Builtin.unwrap
+
+          /// Get the parsed document
+          let parsed = doc |> (fun doc -> doc.parsed)
+          let parsedToPT = doc |> (fun doc -> doc.parsedToPT) // TODO: use this
+
+          /// Find the node at the hover position, and get the hover information
+          let info =
+            match parsed with
+            | Ok(SourceFile s) ->
+              let decls =
+                s.declarations
+                |> HoverInformation.collectNodeHoverInfoAtPos position []
+
+              // First try to find a declaration at the position, then try to find expressions
+              match decls with
+              | Some _ -> decls
+              | None ->
+                s.exprsToEval
+                |> Stdlib.List.filterMap (fun e ->
+                  HoverInformation.collectExpressionHoverInfoAtPos e position [])
+                |> Stdlib.List.head
+
+            | _ -> Stdlib.Option.Option.None
+
+
+          /// Get the text, metadata, and description for the hover
+          let (hoveringOn, metadata, description) =
+            match info with
+            | Some i ->
+              let text =
+                doc
+                |> (fun doc -> doc.text)
+                |> (fun text ->
+                  match HoverInformation.getTextAtRange text i.range with
+                  | Some t -> t
+                  | None -> "")
+
+              let metadata =
+                i.metadata |> Stdlib.Option.withDefault "No metadata available"
+
+              let description =
+                match i.description with
+                | Some d -> "\n\nDescription: \n\n" ++ d
+                | None -> "no description available"
+
+              (text, metadata, description)
+
+            | None -> ("", "No metadata available", "No description available") // TODO: remove this, we shouldn't show hover if there's no info
+
+
           // Create a hover response with Markdown content
           let hover =
             LanguageServerProtocol.Hover.Hover
               { contents =
                   LanguageServerProtocol.MarkupContent
                     { kind = LanguageServerProtocol.MarkupKind.Markdown
-                      value = "got a **hover** response \n\n yay!" }
+                      value =
+                        (HoverInformation.createCodeSnippet hoveringOn)
+                        ++ "\n\n"
+                        ++ metadata
+                        ++ "\n\n"
+                        ++ description }
+
                 range = Stdlib.Option.Option.None }
 
           let response =