feat(repl): support multi-line inputs and declarations (gnolang#978)

gnovm/cmd/gno/repl.go

@@ -2,19 +2,15 @@ package main
 
 import (
 	"bufio"
+	"bytes"
 	"context"
-	"errors"
 	"flag"
 	"fmt"
-	"io"
 	"os"
-	"strconv"
 	"strings"
 
-	gno "github.com/gnolang/gno/gnovm/pkg/gnolang"
-	"github.com/gnolang/gno/gnovm/tests"
+	"github.com/gnolang/gno/gnovm/pkg/repl"
 	"github.com/gnolang/gno/tm2/pkg/commands"
-	"golang.org/x/term"
 )
 
 type replCfg struct {
@@ -89,170 +85,94 @@ func execRepl(cfg *replCfg, args []string) error {
 
 	if !cfg.skipUsage {
 		fmt.Fprint(os.Stderr, `// Usage:
-//   gno:1> /import "gno.land/p/demo/avl"     // import the p/demo/avl package
-//   gno:2> /func a() string { return "a" }   // declare a new function named a
-//   gno:3> /src                              // print current generated source
-//   gno:4> println(a())                      // print the result of calling a()
-//   gno:5> /exit
+//   gno> import "gno.land/p/demo/avl"     // import the p/demo/avl package
+//   gno> func a() string { return "a" }   // declare a new function named a
+//   gno> /src                             // print current generated source
+//   gno> /editor                          // enter in editor mode to add several lines
+//   gno> /reset                           // remove all previously inserted code
+//   gno> println(a())                     // print the result of calling a()
+//   gno> /exit
 `)
 	}
 
 	return runRepl(cfg)
 }
 
-type repl struct {
-	// repl state
-	imports   []string
-	funcs     []string
-	lastInput string
-	i         int
-	// TODO: support setting global vars
-	// TODO: switch to state machine, and support rollback of anything
-
-	stderr  io.Writer
-	stdout  io.Writer
-	machine *gno.Machine
-}
+func runRepl(cfg *replCfg) error {
+	// init repl state
+	r := repl.NewRepl()
 
-func (r *repl) handleInput(input string) error {
-	if strings.TrimSpace(input) == "" {
-		return nil
+	if cfg.initialCommand != "" {
+		handleInput(r, cfg.initialCommand)
 	}
 
-	r.i++
-	funcName := fmt.Sprintf("repl_%d", r.i)
-	// FIXME: support ";" as line separator?
-	// FIXME: support multiline when unclosed parenthesis, etc
-
-	imports := strings.Join(r.imports, "\n")
-	funcs := strings.Join(r.funcs, "\n")
-	srcBefore := "// generated by 'gno repl'\npackage test\n" + imports + "\n" + funcs + "\nfunc " + funcName + "() {\n"
-	srcAfter := "\n}"
+	var multiline bool
+	for {
+		fmt.Fprint(os.Stdout, "gno> ")
 
-	fields := strings.Fields(input)
-	command := fields[0]
-	switch {
-	case command == "/import":
-		imp := fields[1]
-		if strings.HasPrefix(imp, `"`) {
-			imp, _ = strconv.Unquote(imp) // support with or without quotes
-		}
-		imp = strings.TrimSpace(imp)
-		if imp == "" {
-			fmt.Fprintf(r.stdout, "invalid import: %q\n", imp)
-			return nil
+		input, err := getInput(multiline)
+		if err != nil {
+			return err
 		}
-		r.imports = append(r.imports, `import "`+imp+`"`)
-		// TODO: check if valid, else rollback
-		return nil
-	case command == "/func":
-		r.funcs = append(r.funcs, input[1:])
-		// TODO: check if valid, else rollback
-		return nil
-	case command == "/src":
-		// TODO: use go/format for pretty print
-		src := srcBefore + r.lastInput + srcAfter
-		fmt.Fprintln(r.stdout, src)
-		return nil
-	case command == "/exit":
-		os.Exit(0) // return special err?
-	case strings.HasPrefix(command, "/"):
-		fmt.Fprintln(r.stdout, "unsupported command")
-		return nil
-	default:
-		// not a command, probably code to run
-	}
 
-	r.lastInput = input
-	src := srcBefore + r.lastInput + srcAfter
-	n := gno.MustParseFile(funcName+".gno", src)
-	// TODO: run fmt check + linter
-	r.machine.RunFiles(n)
-	// TODO: smart recover system
-	r.machine.RunStatement(gno.S(gno.Call(gno.X(funcName))))
-	// TODO: if output is empty, consider that it's a persisted variable?
-	return nil
+		multiline = handleInput(r, input)
+	}
 }
 
-func runRepl(cfg *replCfg) error {
-	stdin := os.Stdin
-	stdout := os.Stdout
-	stderr := os.Stderr
-
-	// init repl state
-	r := repl{
-		i:         1,
-		stdout:    stdout,
-		stderr:    stderr,
-		imports:   make([]string, 0),
-		funcs:     make([]string, 0),
-		lastInput: "// your code will be here", // initial value, to make it easier to identify with '/src'
-	}
-	for _, imp := range strings.Split(cfg.initialImports, ",") {
-		if strings.TrimSpace(imp) == "" {
-			continue
+// handleInput reads the input string and parses it depending if it
+// is a specific command, or source code. It returns true if the following
+// input is expected to be on more than one line.
+func handleInput(r *repl.Repl, input string) bool {
+	switch strings.TrimSpace(input) {
+	case "/reset":
+		r.Reset()
+	case "/src":
+		fmt.Fprintln(os.Stdout, r.Src())
+	case "/exit":
+		os.Exit(0)
+	case "/editor":
+		fmt.Fprintln(os.Stdout, "// Entering editor mode (^D to finish)")
+		return true
+	case "":
+		// avoid to increase the repl execution counter if sending empty content
+		fmt.Fprintln(os.Stdout, "")
+		return false
+	default:
+		out, err := r.Process(input)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err)
 		}
-		r.imports = append(r.imports, `import "`+imp+`"`)
-	}
-	testStore := tests.TestStore(cfg.rootDir, "", stdin, stdout, stderr, tests.ImportModeStdlibsOnly)
-	if cfg.verbose {
-		testStore.SetLogStoreOps(true)
-	}
-	r.machine = gno.NewMachineWithOptions(gno.MachineOptions{
-		PkgPath: "test",
-		Output:  stdout,
-		Store:   testStore,
-	})
-	defer r.machine.Release()
-
-	if cfg.initialCommand != "" {
-		r.handleInput(cfg.initialCommand)
+		fmt.Fprintln(os.Stdout, out)
 	}
 
-	// main loop
-	isTerm := term.IsTerminal(int(stdin.Fd()))
+	return false
+}
 
-	if isTerm {
-		rw := struct {
-			io.Reader
-			io.Writer
-		}{os.Stdin, os.Stderr}
-		t := term.NewTerminal(rw, "")
-		for {
-			// prompt and parse
-			t.SetPrompt(fmt.Sprintf("gno:%d> ", r.i))
-			oldState, err := term.MakeRaw(0)
-			if err != nil {
-				return fmt.Errorf("make term raw: %w", err)
-			}
-			input, err := t.ReadLine()
-			if err != nil {
-				term.Restore(0, oldState)
-				if errors.Is(err, io.EOF) {
-					return nil
-				}
-				return fmt.Errorf("term error: %w", err)
-			}
-			term.Restore(0, oldState)
+const (
+	inputBreaker = "^D"
+	nl           = "\n"
+)
 
-			err = r.handleInput(input)
-			if err != nil {
-				return fmt.Errorf("handle repl input: %w", err)
-			}
+func getInput(ml bool) (string, error) {
+	s := bufio.NewScanner(os.Stdin)
+	var mlOut bytes.Buffer
+	for s.Scan() {
+		line := s.Text()
+		if !ml {
+			return line, nil
 		}
-	} else { // !isTerm
-		scanner := bufio.NewScanner(stdin)
-		for scanner.Scan() {
-			input := scanner.Text()
-			err := r.handleInput(input)
-			if err != nil {
-				return fmt.Errorf("handle repl input: %w", err)
-			}
-		}
-		err := scanner.Err()
-		if err != nil {
-			return fmt.Errorf("read stdin: %w", err)
+
+		if line == inputBreaker {
+			break
 		}
+
+		mlOut.WriteString(line)
+		mlOut.WriteString(nl)
 	}
-	return nil
+
+	if err := s.Err(); err != nil {
+		return "", err
+	}
+
+	return mlOut.String(), nil
 }