Support textDocument/inlineCompletion request from 3.18

[rcjsuen]

I used #30 as an example for adding support for the new textDocument/inlineCompletion request introduced in 3.18. @tliron I know copy/pasting isn't the best of ideas but it can help get people unblocked for now. What do you think?

I tested it by having Visual Studio Code connect to the language server below and triggering the textDocument/inlineCompletion request from the editor.

package main

import (
	"github.com/tliron/commonlog"
	"github.com/tliron/glsp"
	protocol316 "github.com/tliron/glsp/protocol_3_16"
	protocol317 "github.com/tliron/glsp/protocol_3_17"
	protocol318 "github.com/tliron/glsp/protocol_3_18"
	"github.com/tliron/glsp/server"
)

const lsName = "my language"

var (
	version string = "0.0.1"
	handler protocol318.Handler
)

func main() {
	// This increases logging verbosity (optional)
	commonlog.Configure(1, nil)

	handler = protocol318.Handler{
		Initialize: initialize,
		TextDocumentInlineCompletion: func(context *glsp.Context, params *protocol318.InlineCompletionParams) (any, error) {
			return []protocol318.InlineCompletionItem{
				{
					InsertText: "hello world",
					Range: &protocol316.Range{
						Start: protocol316.Position{
							Line:      0,
							Character: 0,
						},
						End: protocol316.Position{
							Line:      0,
							Character: 0,
						},
					},
				},
			}, nil
		},
		Handler: protocol317.Handler{
			Handler: protocol316.Handler{
				Initialized: initialized,
				Shutdown:    shutdown,
				SetTrace:    setTrace,
			},
		},
	}

	server := server.NewServer(&handler, lsName, false)

	server.RunStdio()
}

func initialize(context *glsp.Context, params *protocol318.InitializeParams) (any, error) {
	capabilities := handler.CreateServerCapabilities()

	return protocol318.InitializeResult{
		Capabilities: capabilities,
		ServerInfo: &protocol316.InitializeResultServerInfo{
			Name:    lsName,
			Version: &version,
		},
	}, nil
}

func initialized(context *glsp.Context, params *protocol316.InitializedParams) error {
	return nil
}

func shutdown(context *glsp.Context) error {
	protocol316.SetTraceValue(protocol316.TraceValueOff)
	return nil
}

func setTrace(context *glsp.Context, params *protocol316.SetTraceParams) error {
	protocol316.SetTraceValue(params.Value)
	return nil
}

[tris203]

Hi @rcjsuen,
Thanks for your contribution!
I've recently taken over maintenance of this library and I'm excited about this. I'd love to bring full support for all LSP 3.18 methods.
I'm currently weighing up whether to merge this as a shortcut, or to implement a protocol factory or builder to reduce duplication.

[rcjsuen]

@tris203 Do whatever you think is best for the project. :)

In our case, we ended up copying the code into our repository (also under Apache v2) and merged the versions together instead of trying to deal with the version differences.