cmd/govim: add Hover function to give equivalent string to balloonexpr (

#118)

cmd/govim/config/config.go

@@ -23,6 +23,7 @@ const (
 	FunctionBalloonExpr Function = "BalloonExpr"
 	FunctionComplete    Function = "Complete"
 	FunctionHello       Function = "Hello"
+	FunctionHover       Function = "Hover"
 )
 
 type FormatOnSave string

cmd/govim/functions.go

@@ -412,3 +412,24 @@ func (v *vimstate) loadLocation(loc protocol.Location) error {
 
 	return nil
 }
+
+func (v *vimstate) hover(args ...json.RawMessage) (interface{}, error) {
+	b, pos, err := v.cursorPos()
+	if err != nil {
+		return nil, fmt.Errorf("failed to get current position: %v", err)
+	}
+	params := &protocol.TextDocumentPositionParams{
+		TextDocument: protocol.TextDocumentIdentifier{
+			URI: string(b.URI()),
+		},
+		Position: pos.ToPosition(),
+	}
+	res, err := v.server.Hover(context.Background(), params)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get hover details: %v", err)
+	}
+	md := []byte(res.Contents.Value)
+	plain := string(blackfriday.Run(md, blackfriday.WithRenderer(plainMarkdown{})))
+	plain = strings.TrimSpace(plain)
+	return plain, nil
+}

cmd/govim/main.go

@@ -147,6 +147,7 @@ func (g *govimplugin) Init(gg govim.Govim, errCh chan error) error {
 	g.DefineFunction(string(config.FunctionComplete), []string{"findarg", "base"}, g.complete)
 	g.DefineCommand(string(config.CommandGoToDef), g.gotoDef, govim.NArgsZeroOrOne)
 	g.DefineCommand(string(config.CommandGoToPrevDef), g.gotoPrevDef, govim.NArgsZeroOrOne, govim.CountN(1))
+	g.DefineFunction(string(config.FunctionHover), []string{}, g.hover)
 
 	g.isGui = g.ParseInt(g.ChannelExpr(`has("gui_running")`)) == 1
 

cmd/govim/testdata/function_hover.txt

@@ -0,0 +1,19 @@
+# Test that basic functions work
+
+vim ex 'e main.go'
+vim ex 'call cursor(6,6)'
+vim expr 'GOVIMHover()'
+stdout '^\Q"func fmt.Println(a ...interface{}) (n int, err error)"\E$'
+! stderr .+
+
+-- go.mod --
+module mod.com
+
+-- main.go --
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("Hello, world")
+}