Added initial LSP support.

This pull-request, once complete, will had LSP support and
will close #108.

Currently we show help for standard library functions, when
the user hovers over a token.  We also provide completion for
all our standard-library functions.

go.mod

@@ -1,3 +1,28 @@
 module github.com/skx/yal
 
 go 1.18
+
+require (
+	github.com/tliron/glsp v0.1.1
+	github.com/tliron/kutil v0.1.63
+	go.lsp.dev/uri v0.3.0
+)
+
+require (
+	github.com/gorilla/websocket v1.5.0 // indirect
+	github.com/iancoleman/strcase v0.2.0 // indirect
+	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
+	github.com/mattn/go-isatty v0.0.14 // indirect
+	github.com/mattn/go-runewidth v0.0.13 // indirect
+	github.com/muesli/termenv v0.12.0 // indirect
+	github.com/petermattis/goid v0.0.0-20180202154549-b0b1615b78e5 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/rivo/uniseg v0.2.0 // indirect
+	github.com/sasha-s/go-deadlock v0.3.1 // indirect
+	github.com/sourcegraph/jsonrpc2 v0.1.0 // indirect
+	github.com/vmihailenco/msgpack/v5 v5.3.5 // indirect
+	github.com/vmihailenco/tagparser/v2 v2.0.0 // indirect
+	golang.org/x/crypto v0.0.0-20220722155217-630584e8d5aa // indirect
+	golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10 // indirect
+	golang.org/x/term v0.0.0-20220722155259-a9ba230a4035 // indirect
+)

go.sum

@@ -0,0 +1,49 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/gorilla/websocket v1.4.1/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWmnc=
+github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+github.com/iancoleman/strcase v0.2.0 h1:05I4QRnGpI0m37iZQRuskXh+w77mr6Z41lwQzuHLwW0=
+github.com/iancoleman/strcase v0.2.0/go.mod h1:iwCmte+B7n89clKwxIoIXy/HfoL7AsD47ZCWhYzw7ho=
+github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
+github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
+github.com/mattn/go-isatty v0.0.14 h1:yVuAays6BHfxijgZPzw+3Zlu5yQgKGP2/hcQbHb7S9Y=
+github.com/mattn/go-isatty v0.0.14/go.mod h1:7GGIvUiUoEMVVmxf/4nioHXj79iQHKdU27kJ6hsGG94=
+github.com/mattn/go-runewidth v0.0.13 h1:lTGmDsbAYt5DmK6OnoV7EuIF1wEIFAcxld6ypU4OSgU=
+github.com/mattn/go-runewidth v0.0.13/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
+github.com/muesli/termenv v0.12.0 h1:KuQRUE3PgxRFWhq4gHvZtPSLCGDqM5q/cYr1pZ39ytc=
+github.com/muesli/termenv v0.12.0/go.mod h1:WCCv32tusQ/EEZ5S8oUIIrC/nIuBcxCVqlN4Xfkv+7A=
+github.com/petermattis/goid v0.0.0-20180202154549-b0b1615b78e5 h1:q2e307iGHPdTGp0hoxKjt1H5pDo6utceo3dQVK3I5XQ=
+github.com/petermattis/goid v0.0.0-20180202154549-b0b1615b78e5/go.mod h1:jvVRKCrJTQWu0XVbaOlby/2lO20uSCHEMzzplHXte1o=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/rivo/uniseg v0.2.0 h1:S1pD9weZBuJdFmowNwbpi7BJ8TNftyUImj/0WQi72jY=
+github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
+github.com/sasha-s/go-deadlock v0.3.1 h1:sqv7fDNShgjcaxkO0JNcOAlr8B9+cV5Ey/OB71efZx0=
+github.com/sasha-s/go-deadlock v0.3.1/go.mod h1:F73l+cr82YSh10GxyRI6qZiCgK64VaZjwesgfQ1/iLM=
+github.com/sourcegraph/jsonrpc2 v0.1.0 h1:ohJHjZ+PcaLxDUjqk2NC3tIGsVa5bXThe1ZheSXOjuk=
+github.com/sourcegraph/jsonrpc2 v0.1.0/go.mod h1:ZafdZgk/axhT1cvZAPOhw+95nz2I/Ra5qMlU4gTRwIo=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/tliron/glsp v0.1.1 h1:GNNgUX9p1Q9MoPQooJoZ0+WaLL03EkhcKZUYJAtiNqs=
+github.com/tliron/glsp v0.1.1/go.mod h1:RVyVKeY3U+Nlc3DRklUiaegNsQyjzNTEool6YWh1v7g=
+github.com/tliron/kutil v0.1.63 h1:/xOqEShxPymwhcVcPFAks8zj43HU+NljbmzYjNXIO+Y=
+github.com/tliron/kutil v0.1.63/go.mod h1:Mo1pAtg/9yG3ClnUv32Hrl+t0BFFCg49RpCjHG3sY7c=
+github.com/vmihailenco/msgpack/v5 v5.3.5 h1:5gO0H1iULLWGhs2H5tbAHIZTV8/cYafcFOr9znI5mJU=
+github.com/vmihailenco/msgpack/v5 v5.3.5/go.mod h1:7xyJ9e+0+9SaZT0Wt1RGleJXzli6Q/V5KbhBonMG9jc=
+github.com/vmihailenco/tagparser/v2 v2.0.0 h1:y09buUbR+b5aycVFQs/g70pqKVZNBmxwAhO7/IwNM9g=
+github.com/vmihailenco/tagparser/v2 v2.0.0/go.mod h1:Wri+At7QHww0WTrCBeu4J6bNtoV6mEfg5OIWRZA9qds=
+go.lsp.dev/uri v0.3.0 h1:KcZJmh6nFIBeJzTugn5JTU6OOyG0lDOo3R9KwTxTYbo=
+go.lsp.dev/uri v0.3.0/go.mod h1:P5sbO1IQR+qySTWOCnhnK7phBx+W3zbLqSMDJNTw88I=
+golang.org/x/crypto v0.0.0-20220722155217-630584e8d5aa h1:zuSxTR4o9y82ebqCUJYNGJbGPo6sKVl54f/TVDObg1c=
+golang.org/x/crypto v0.0.0-20220722155217-630584e8d5aa/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
+golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220209214540-3681064d5158/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10 h1:WIoqL4EROvwiPdUtaip4VcDdpZ4kha7wBWZrbVKCIZg=
+golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20220722155259-a9ba230a4035 h1:Q5284mrmYTpACcm+eAKjKJH48BBwSyfJqmmGDTtT8Vc=
+golang.org/x/term v0.0.0-20220722155259-a9ba230a4035/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

lsp.go

@@ -0,0 +1,178 @@
+// This file provides our LSP support.
+//
+// When yal is invoked with the "-lsp" flag we call lspStart(),
+// which provides simple completion and hover support.
+//
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"sort"
+
+	"github.com/skx/yal/primitive"
+	"github.com/tliron/glsp"
+	protocol "github.com/tliron/glsp/protocol_3_16"
+	"github.com/tliron/glsp/server"
+	"github.com/tliron/kutil/logging"
+	"go.lsp.dev/uri"
+
+	// Must include a backend implementation. See kutil's logging/ for other options.
+	_ "github.com/tliron/kutil/logging/simple"
+)
+
+// lsName contains the name of our LSP handler
+const lsName = "yal"
+
+// handler contains the pointer to our handler
+var handler protocol.Handler
+
+// initialize is called to setup a new buffer.
+func initialize(context *glsp.Context, params *protocol.InitializeParams) (any, error) {
+	capabilities := handler.CreateServerCapabilities()
+
+	return protocol.InitializeResult{
+		Capabilities: capabilities,
+		ServerInfo: &protocol.InitializeResultServerInfo{
+			Name:    "yal",
+			Version: &version,
+		},
+	}, nil
+}
+
+func lspStart() {
+	logging.Configure(1, nil)
+
+	handler = protocol.Handler{
+		// generic
+		Initialize: initialize,
+
+		// Yal Specific
+		TextDocumentCompletion: textDocumentCompletion,
+		TextDocumentHover:      textDocumentHover,
+	}
+
+	server := server.NewServer(&handler, lsName, false)
+
+	server.RunStdio()
+}
+
+// textDocumentCompletion should return appropriate completions.
+//
+// However we just always return a list of all known functions, the
+// client can sort it out.
+func textDocumentCompletion(context *glsp.Context, params *protocol.CompletionParams) (interface{}, error) {
+
+	// Build up a list of all things known in the environment
+	keys := []string{}
+
+	// Save the known "things", because we want show them in sorted-order.
+	items := ENV.Items()
+	for k := range items {
+		keys = append(keys, k)
+	}
+
+	// sort the known-things (i.e. environment keys)
+	sort.Strings(keys)
+
+	// Create the return value
+	out := make([]protocol.CompletionItem, len(keys))
+
+	// The kind of completion we have
+	kind := protocol.CompletionItemKindFunction
+
+	// Now we have a list of sorted things.
+	for i, key := range keys {
+
+		out[i] = protocol.CompletionItem{
+			Label:  key,
+			Kind:   &kind,
+			Detail: &key,
+		}
+	}
+	return out, nil
+}
+
+// textDocumentHover is called when the client hovers over a token
+//
+// We need to find out what text is being hovered over, and return
+// something "useful" to the client.
+func textDocumentHover(context *glsp.Context, params *protocol.HoverParams) (*protocol.Hover, error) {
+
+	// Get the file
+	_uri, err := uri.Parse(params.TextDocument.URI)
+	if err != nil {
+		return nil, err
+	}
+
+	// open the file
+	var content []byte
+
+	// read the content
+	content, err = os.ReadFile(_uri.Filename())
+	if err != nil {
+		return nil, err
+	}
+
+	// We'll build up the current line, being hovered on here
+	var curLine uint32
+	line := ""
+
+	// count the newlines to get the current line.
+	for _, chr := range content {
+		if chr == '\n' {
+			curLine++
+			continue
+		}
+		if curLine == params.Position.Line {
+			line += string(chr)
+		}
+	}
+
+	// current line is empty?  Then abort
+	if line == "" {
+		return nil, nil
+	}
+
+	// Right now we have the line we want the token
+	//
+	// Assume we have a line like "(this is (cake))"
+	// and position points to the "c" we want to have the
+	// whole token
+	//
+	token := ""
+
+	for i, chr := range line {
+		if chr == rune(' ') || chr == rune('(') || chr == rune(')') || chr == rune('\t') {
+			if uint32(i) > params.Position.Character {
+				break
+			}
+			token = ""
+			continue
+		}
+		token += string(chr)
+	}
+
+	// Find the details of the function, if we can
+	info, ok := ENV.Get(token)
+	if !ok {
+		return nil, nil
+	}
+
+	// Is it a procedure?
+	prc, ok2 := info.(*primitive.Procedure)
+	if !ok2 {
+		return nil, nil
+	}
+
+	// The text we'll show.
+	help := fmt.Sprintf("**%s**\n%s", token, prc.Help)
+
+	return &protocol.Hover{
+		Contents: protocol.MarkupContent{
+			Kind:  protocol.MarkupKindMarkdown,
+			Value: help,
+		},
+	}, nil
+}

main.go

@@ -3,8 +3,6 @@
 // All the logic is contained within the `main` function, and it merely
 // reads the contents of the user-supplied filename, prepends the standard
 // library to that content, and executes it.
-//
-// Notably we don't contain a REPL-mode at the moment.
 package main
 
 import (
@@ -189,6 +187,7 @@ func main() {
 	// Parse our command-line flags
 	exp := flag.String("e", "", "A string to evaluate.")
 	hlp := flag.Bool("h", false, "Show help information and exit.")
+	lsp := flag.Bool("lsp", false, "Launch the LSP mode")
 	ver := flag.Bool("v", false, "Show our version and exit.")
 	flag.Parse()
 
@@ -213,6 +212,12 @@ func main() {
 	//
 	create()
 
+	// LSP?
+	if *lsp {
+		lspStart()
+		return
+	}
+
 	// showing the help?
 	if *hlp {
 		help(flag.Args())