replace runner.JumpTo(node) by runner.RestoreAt(snapshot)

runner.go

@@ -19,16 +19,17 @@ import (
 // It keeps track of the current state of the dialogue (variables, current and visited steps).
 // It orchestrates the call of Commands and Functions.
 type DialogueRunner struct {
-	dialogue        *tree.Dialogue
-	statementsToRun container.Stack[*statementQueue]
-	lastStatement   *tree.Statement
-	variableStorer  variable.Storer
-	functionStorer  *functionStorer
-	commandStorer   *commandStorer
-	commandErrChan  <-chan error
-	lineParser      markup.LineParser
-	currentNode     string
-	visitedNodes    map[string]int
+	dialogue         *tree.Dialogue
+	statementsToRun  container.Stack[*statementQueue]
+	lastStatement    *tree.Statement
+	variableStorer   variable.Storer
+	functionStorer   *functionStorer
+	commandStorer    *commandStorer
+	commandErrChan   <-chan error
+	lineParser       markup.LineParser
+	currentNode      string
+	visitedNodes     map[string]int
+	variableSnapshot map[string]variable.Value
 }
 
 // DialogueElement represents a step of a dialogue as it is presented in a game.
@@ -303,6 +304,7 @@ func (dr *DialogueRunner) executeJumpStatement(statement *tree.JumpStatement) er
 		return fmt.Errorf("node [%s] not found in dialogue", *value.String)
 	} else {
 		dr.incrementNodeTrackingIfAllowed()
+		dr.variableSnapshot = dr.variableStorer.GetValues()
 		dr.statementsToRun.Clear()
 		dr.statementsToRun.Push(&statementQueue{statements: node.Statements})
 		dr.currentNode = node.Title()
@@ -394,13 +396,27 @@ func (dr *DialogueRunner) executeDeclareStatement(statement *tree.DeclareStateme
 	})
 }
 
-// JumpTo moves the dialogue to the beginning of the given node.
-func (dr *DialogueRunner) JumpTo(nodeTitle string) error {
-	node, ok := dr.dialogue.FindNode(nodeTitle)
+// RestoreAt uses a snapshot to restore a dialogue runner to a former state.
+func (dr *DialogueRunner) RestoreAt(snapshot *Snapshot) error {
+	node, ok := dr.dialogue.FindNode(snapshot.CurrentNode)
 	if !ok {
-		return fmt.Errorf("dialogue does not contain a node with title [%s]", nodeTitle)
+		return fmt.Errorf("dialogue does not contain a node with title [%s]", snapshot.CurrentNode)
 	}
-	dr.incrementNodeTrackingIfAllowed()
+
+	dr.visitedNodes = snapshot.VisitedNodes
+	dr.variableStorer.Clear()
+	for variable, value := range snapshot.Variables {
+		if value.Boolean != nil {
+			dr.variableStorer.SetBooleanValue(variable, *value.Boolean)
+		}
+		if value.Number != nil {
+			dr.variableStorer.SetNumberValue(variable, *value.Number)
+		}
+		if value.String != nil {
+			dr.variableStorer.SetStringValue(variable, *value.String)
+		}
+	}
+
 	dr.statementsToRun.Clear()
 	dr.statementsToRun.Push(&statementQueue{statements: node.Statements})
 	dr.currentNode = node.Title()
@@ -429,9 +445,14 @@ func (dr *DialogueRunner) ConvertAndAddCommand(commandID string, command any) er
 	return dr.commandStorer.convertAndAddCommand(commandID, command)
 }
 
-// CurrentNode returns the name of the node the runner is currently visiting.
-func (dr *DialogueRunner) CurrentNode() string {
-	return dr.currentNode
+// Snapshot returns the state of the dialogue runner as of the last time a node was entered.
+// It can then be used to later restore the state of the dialogue runner.
+func (dr *DialogueRunner) Snapshot() *Snapshot {
+	return &Snapshot{
+		Variables:    dr.variableSnapshot,
+		CurrentNode:  dr.currentNode,
+		VisitedNodes: dr.visitedNodes,
+	}
 }
 
 type statementQueue struct {

runner_test.go

@@ -157,18 +157,22 @@ func TestRunnerPlan(t *testing.T) {
 	}
 }
 
-func TestRunnerJumpTo(t *testing.T) {
+func TestRunnerRestoreAt(t *testing.T) {
 	script := `
-title: flavors
+title: node_1
 ---
-Do you like chocolate?
-Yes!
-Nice! Here, get some icecream!
+Do you like chocolate? Here, get some icecream!
+<<declare $flavor to "chocolate">>
+Thanks!
+<<jump node_2>>
 ===
-title: bakery
+title: node_2
 ---
-How much for a baguette?
-About 1€!
+You like {$flavor}, right? Here's more icecream!
+Actually, I'd like raspberries this time!
+<<declare $flavor to "raspberries">>
+Oh ok, {$flavor} it is then!
+Thanks!
 ===`
 
 	dr, err := ysgo.NewDialogueRunner(nil, "", strings.NewReader(script))
@@ -177,29 +181,29 @@ About 1€!
 		return
 	}
 
-	dialogueElement, err := dr.Next(0)
-	if err != nil {
-		t.Errorf("failed to get to first dialogue element: %v", err)
-		return
-	}
-	if expected, actual := "Do you like chocolate?", dialogueElement.Line.Text; expected != actual {
-		t.Errorf("unexpected line text: wanted [%s], got [%s]", expected, actual)
-		return
+	assertNextLine := func(expectedLine string) {
+		dialogueElement, err := dr.Next(0)
+		if err != nil {
+			t.Errorf("failed to get to dialogue element: %v", err)
+			return
+		}
+		if expected, actual := expectedLine, dialogueElement.Line.Text; expected != actual {
+			t.Errorf("unexpected line text: wanted [%s], got [%s]", expected, actual)
+			return
+		}
 	}
 
-	err = dr.JumpTo("bakery")
-	if err != nil {
-		t.Errorf("jump to bakery node failed: %v", err)
-		return
-	}
+	assertNextLine("Do you like chocolate? Here, get some icecream!")
+	assertNextLine("Thanks!")
+	assertNextLine("You like chocolate, right? Here's more icecream!")
+	assertNextLine("Actually, I'd like raspberries this time!")
+	assertNextLine("Oh ok, raspberries it is then!")
 
-	dialogueElement, err = dr.Next(0)
-	if err != nil {
-		t.Errorf("failed to get to first dialogue element: %v", err)
-		return
-	}
-	if expected, actual := "How much for a baguette?", dialogueElement.Line.Text; expected != actual {
-		t.Errorf("unexpected line text: wanted [%s], got [%s]", expected, actual)
-		return
+	snapshot := dr.Snapshot()
+
+	if err := dr.RestoreAt(snapshot); err != nil {
+		t.Errorf("unexpected error when restoring snapshot: %v", err)
 	}
+
+	assertNextLine("You like chocolate, right? Here's more icecream!")
 }

snapshot.go

@@ -0,0 +1,13 @@
+package ysgo
+
+import "github.com/remieven/ysgo/variable"
+
+// Snapshot holds data that represents the current state of a dialogue, so it can be restored later
+type Snapshot struct {
+	Variables map[string]variable.Value
+
+	CurrentNode string
+
+	VisitedNodes map[string]int
+}
+

variable/in_memory_storer.go

@@ -26,6 +26,23 @@ func (storer *InMemoryStorer) GetValue(variableName string) (*Value, bool) {
 	return nil, false
 }
 
+// GetValues returns a map of all stored values.
+func (storer *InMemoryStorer) GetValues() map[string]Value {
+	values := make(map[string]Value, len(storer.booleans)+len(storer.numbers)+len(storer.strings))
+
+	for variable, value := range storer.booleans {
+		values[variable] = *NewBoolean(value)
+	}
+	for variable, value := range storer.numbers {
+		values[variable] = *NewNumber(value)
+	}
+	for variable, value := range storer.strings {
+		values[variable] = *NewString(value)
+	}
+
+	return values
+}
+
 // SetNumberValue stores a number.
 func (storer *InMemoryStorer) SetNumberValue(variableName string, value float64) {
 	storer.numbers[variableName] = value

variable/in_memory_storer_test.go

@@ -1,6 +1,10 @@
 package variable
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/remieven/ysgo/internal/testutils"
+)
 
 func TestInMemoryStorer(t *testing.T) {
 	storer := NewInMemoryStorer()
@@ -145,4 +149,32 @@ func TestInMemoryStorer(t *testing.T) {
 			return
 		}
 	})
+
+	t.Run("Export of empty store", func(t *testing.T) {
+		storer := NewInMemoryStorer()
+
+		if len(storer.GetValues()) != 0 {
+			t.Errorf("expected GetValues of empty storer to return 0 values but got %v", len(storer.GetValues()))
+		}
+	})
+
+	t.Run("Export of filled store", func(t *testing.T) {
+		storer := NewInMemoryStorer()
+		storer.SetBooleanValue("bool1", true)
+		storer.SetBooleanValue("bool2", false)
+		storer.SetNumberValue("number", 70400)
+		storer.SetStringValue("string", "some string value")
+
+		expected := map[string]Value{
+			"bool1":  *NewBoolean(true),
+			"bool2":  *NewBoolean(false),
+			"number": *NewNumber(70400),
+			"string": *NewString("some string value"),
+		}
+
+		if diff := testutils.DeepEqual(storer.GetValues(), expected); diff != "" {
+			t.Errorf("unexpected result from GetValues: " + diff)
+		}
+
+	})
 }

variable/storer.go

@@ -4,6 +4,8 @@ package variable
 type Retriever interface {
 	GetValue(variableName string) (*Value, bool)
 
+	GetValues() map[string]Value
+
 	Contains(variableName string) bool
 }