Add scripting

.github/workflows/build.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        go: [ 1.18 ]
+        go: [ 1.20 ]
     env:
       DISPLAY: ':99.0'
     steps:

README.md

@@ -39,7 +39,7 @@ Pi is under development. Only limited functionality is provided. API is not stab
 ## How to get started?
 
 1. Install dependencies 
-   * [Go 1.18+](https://go.dev/dl/)
+   * [Go 1.20+](https://go.dev/dl/)
    * If not on Windows, please install additional dependencies for [Linux](docs/install-linux.md) or [macOS](docs/install-macos.md).
 2. Try examples from [examples](examples) directory.
 3. Create a new game using provided [Github template](https://github.com/elgopher/pi-template).

devtools/control.go

@@ -4,8 +4,11 @@
 package devtools
 
 import (
+	"fmt"
+
 	"github.com/elgopher/pi"
 	"github.com/elgopher/pi/devtools/internal/snapshot"
+	"github.com/elgopher/pi/devtools/internal/terminal"
 )
 
 var (
@@ -17,10 +20,13 @@ func pauseGame() {
 	gamePaused = true
 	timeWhenPaused = pi.TimeSeconds
 	snapshot.Take()
+	terminal.StartReadingCommands()
 }
 
 func resumeGame() {
 	gamePaused = false
 	pi.TimeSeconds = timeWhenPaused
 	snapshot.Draw()
+	fmt.Println("Game resumed")
+	terminal.StopReadingCommandsFromStdin()
 }

devtools/devtools.go

@@ -33,7 +33,7 @@ func MustRun(runBackend func() error) {
 	}
 
 	inspector.BgColor, inspector.FgColor = BgColor, FgColor
-	fmt.Println("Press F12 to pause the game and show devtools.")
+	fmt.Println("Press F12 in the game window to pause the game and activate devtools with terminal.")
 
 	pi.Update = func() {
 		updateDevTools()

devtools/internal/inspector/measure.go

@@ -94,7 +94,7 @@ func (m *Measure) Update() {
 	case pi.MouseBtnp(pi.MouseLeft) && !distance.measuring:
 		distance.measuring = true
 		distance.startX, distance.startY = x, y
-		fmt.Printf("Measuring started at (%d, %d)\n", x, y)
+		fmt.Printf("\nMeasuring started at (%d, %d)\n", x, y)
 	case !pi.MouseBtn(pi.MouseLeft) && distance.measuring:
 		distance.measuring = false
 		dist, width, height := calcDistance()

devtools/internal/inspector/update.go

@@ -38,8 +38,9 @@ var helpShown bool
 func Update() {
 	if !helpShown {
 		helpShown = true
-		fmt.Println("Press right mouse button to show toolbar.")
-		fmt.Println("Press P to take screenshot.")
+		fmt.Println("\nPress right mouse button in the game window to show the toolbar.")
+		fmt.Println("Press P in the game window to take screenshot.")
+		fmt.Println("Terminal activated.")
 	}
 
 	if !toolbar.visible {

devtools/internal/interpreter/interpreter.go

@@ -0,0 +1,199 @@
+package interpreter
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"go/build"
+	"os"
+	"os/exec"
+	"reflect"
+	"runtime"
+	"strings"
+
+	"github.com/traefik/yaegi/interp"
+
+	"github.com/elgopher/pi/devtools/internal/interpreter/lib"
+	"github.com/elgopher/pi/devtools/internal/snapshot"
+	"github.com/elgopher/pi/devtools/internal/terminal"
+)
+
+func ExportFunc(name string, f any) {
+	err := interpreter.Use(interp.Exports{
+		"main/main": map[string]reflect.Value{
+			name: reflect.ValueOf(f),
+		},
+	})
+	if err != nil {
+		panic(fmt.Sprintf("problem exporting function %s: %s", name, err))
+	}
+
+	_, err = interpreter.Eval(`import . "main"`) // TODO Redeclaration?
+	if err != nil {
+		panic(fmt.Sprintf("problem exporting function %s: %s", name, err))
+	}
+}
+
+func ExportVar(name string, v any) {
+	value := reflect.ValueOf(v)
+	if value.Kind() != reflect.Ptr {
+		panic(fmt.Sprintf("ExportVar: you must pass pointer to variable '%s', but you passed %T. Please add '&' in front.", name, v))
+	}
+	err := interpreter.Use(interp.Exports{
+		"main/main": map[string]reflect.Value{
+			name: value.Elem(),
+		},
+	})
+	if err != nil {
+		panic(fmt.Sprintf("problem exporting variable %s: %s", name, err))
+	}
+
+	_, err = interpreter.Eval(`import . "main"`)
+	if err != nil {
+		panic(fmt.Sprintf("problem exporting variable %s: %s", name, err))
+	}
+}
+
+// TODO Better read name from T
+func ExportType[T any](name string) {
+	var nilValue *T
+	err := interpreter.Use(interp.Exports{
+		"main/main": map[string]reflect.Value{
+			name: reflect.ValueOf(nilValue),
+		},
+	})
+	if err != nil {
+		panic(fmt.Sprintf("problem exporting type %s: %s", name, err))
+	}
+
+	_, err = interpreter.Eval(`import . "main"`)
+	if err != nil {
+		panic(fmt.Sprintf("problem exporting type %s: %s", name, err))
+	}
+}
+
+var interpreter *interp.Interpreter
+
+func init() {
+	interpreter = interp.New(interp.Options{
+		GoPath: gopath(), // if GoPath is set then Yaegi does not complain about setting GOPATH.
+	})
+	err := interpreter.Use(lib.Symbols)
+	if err != nil {
+		_, _ = os.Stderr.WriteString(fmt.Sprintf("problem using Go interpreter symbols: %s", err))
+	}
+
+	_, err = interpreter.Eval(`
+import (
+	"bytes"
+	"fmt"
+	"math"
+	"math/rand"
+	"sort"
+	"strconv"
+	"strings"
+
+	"github.com/elgopher/pi"
+	"github.com/elgopher/pi/font"
+	"github.com/elgopher/pi/image"
+	"github.com/elgopher/pi/key"
+	"github.com/elgopher/pi/snap"
+	"github.com/elgopher/pi/state"
+)
+`)
+	if err != nil {
+		_, _ = os.Stderr.WriteString(fmt.Sprintf("importing interpreter packages failed: %s", err))
+	}
+}
+
+func gopath() string {
+	gopath := os.Getenv("GOPATH")
+	if gopath == "" {
+		gopath = build.Default.GOPATH
+	}
+	return gopath
+}
+
+func EvaluateNextCommand() {
+	select {
+	case cmd := <-terminal.Commands:
+		defer func() {
+			terminal.CommandExecuted <- struct{}{}
+		}()
+		defer func() {
+			err := recover()
+			if err != nil {
+				fmt.Println("panic when running Yaegi", err)
+			}
+		}()
+		if helpCmd := strings.Trim(cmd, " "); strings.HasPrefix(helpCmd, "help ") || helpCmd == "help" {
+			printHelp(strings.Trim(strings.TrimLeft(helpCmd, "help"), " "))
+		} else {
+			runGoCode(cmd)
+		}
+	default:
+		return
+	}
+}
+
+func printHelp(topic string) {
+	switch topic {
+	case "":
+		println("This is interactive terminal. You can write Go code here, which will run immediately in the paused game. You can use all Pi packages and selection of standard packages: bytes, fmt, math, rand, sort, strconv and strings.\n\nType help topic for more information. For example: help pi or help pi.Spr")
+	default:
+		if goDoc(topic) {
+			return
+		}
+	}
+}
+
+func goDoc(symbol string) bool {
+	// TODO PREPEND OTHER PACKAGES TOO
+	if strings.HasPrefix(symbol, "pi.") {
+		symbol = "github.com/elgopher/" + symbol
+	}
+
+	var args []string
+	args = append(args, "doc")
+
+	isPackageName := !strings.Contains(symbol, ".")
+	if !isPackageName {
+		args = append(args, "-all")
+	}
+	args = append(args, symbol)
+	command := exec.Command("go", args...)
+	command.Stdout = bufio.NewWriter(os.Stdout)
+	if err := command.Run(); err != nil {
+		var exitErr *exec.ExitError
+		if isExitErr := errors.As(err, &exitErr); isExitErr && exitErr.ExitCode() == 1 {
+			fmt.Println("no help found")
+			return true
+		}
+		fmt.Println("problem getting help:", err)
+	}
+	return false
+}
+
+func runGoCode(source string) {
+	res, err := interpreter.Eval(source)
+	if err != nil {
+		fmt.Println(err)
+	}
+	snapshot.Take()
+
+	if res.IsValid() {
+		if res.Type().Kind() != reflect.Func {
+			kind := res.Type().Kind()
+			if kind == reflect.Struct {
+				structName := res.Type().PkgPath() + "." + res.Type().Name()
+				structName = structName[strings.LastIndex(structName, "/")+1:]
+				fmt.Printf("%s: %+v\n", structName, res)
+			} else {
+				fmt.Printf("%s: %+v\n", kind, res)
+			}
+		} else {
+			name := runtime.FuncForPC(res.Pointer()).Name()
+			printHelp(name)
+		}
+	}
+}