Add analogue of Functions as Effects like swirl

README.md

@@ -21,6 +21,10 @@ go run main.go flipbook.flip
 
 ## Language Design
 
+5. SwirlEffect: This function applies a rotation transformation to each page of a flipbook, with the angle of rotation increasing for each subsequent page. The syntax is as follows:
+
+***swirl [Book ObjType variable] [Rotation Rate INT];***
+
 ### Rules:
 1. There are two type of objects in this language: Book and Image.
 
@@ -36,7 +40,7 @@ go run main.go flipbook.flip
 
     3.2 Integers: They are any positive integer.
 
-4. There are four types of Statements implemented right now: new, insert, keyframe, save. Every Statement must end with a semicolon.
+4. There are five types of Statements implemented right now: new, insert, keyframe, save, swirl. Every Statement must end with a semicolon.
 
     4.1 ***New***: It creates a new object
     Syntax -
@@ -61,7 +65,16 @@ go run main.go flipbook.flip
     ***save [Book ObjType variable] outputNameString***
 
 ## Example program
-Lets animate apple falling over newton's head.
+Lets animate apple falling over newton's head with a swirl effect.
+```
+new book bookone = ((1600,1600), 25);
+new image newton = ((100,100), "newton.png");
+insert newton bookone from page 1 to 25 at (600,1270);
+new image melon = ((100,100), "melon.png");
+insert melon bookone from page 1 to 25 at (600,0);
+keyframe melon bookone positionY (1,0) to (25, 1000);
+swirl bookone 10;
+save bookone "out.pdf";
 ```
 new book bookone = ((1600,1600), 25);
 new image newton = ((100,100), "newton.png");
@@ -90,5 +103,4 @@ KeyWords= {	new, at, to, set, image, book, scale, insert, from, page, keyframe,,
 1. Compelete the document: Due to the limitation of time, The documentation is not very resourceful.
 2.Clean Up the Code: Due to the same reason, I couldnt get the chance to properly refactor code and comment it.
 3. Add Expression pevaluation via Pratt's Parser technique
-4. Add an analouge of Functions as Effects like swirl
-5. Add more properties like opacity and more statements like 'set'.
+4. Add more properties like opacity and more statements like 'set'.

evaluator/evaluator.go

@@ -7,14 +7,24 @@ import (
 	"github.com/Krishanu230/Flipbook-Language/ast"
 	"github.com/Krishanu230/Flipbook-Language/object"
 
+	"github.com/disintegration/imaging"
+)
+
+func SwirlEffect(pages []object.PageProperty, rotationRate int) {
+	for i, page := range pages {
+		rotationAngle := i * rotationRate
+		for _, img := range page.ImagesProps {
+			img.Image = imaging.Rotate(img.Image, float64(rotationAngle), color.Transparent)
+		}
+	}
 	"github.com/signintech/gopdf"
 )
 
 var (
 	NULL = &object.Null{}
 )
 
-//eval a ast node. recursive nature
+// eval a ast node. recursive nature
 func Eval(node ast.Node, env *object.Environment) object.Object {
 	switch node := node.(type) {
 
@@ -42,6 +52,21 @@ func Eval(node ast.Node, env *object.Environment) object.Object {
 			return val
 		}
 
+	case *ast.SwirlEffectStatement:
+		val := evalSwirlEffect(node, env)
+		if isError(val) {
+			return val
+		}
+	}
+
+	func evalSwirlEffect(node *ast.SwirlEffectStatement, env *object.Environment) object.Object {
+	r := evalIdentifier(node.Book, env)
+	book, ok := r.(*object.Book)
+	if !ok {
+		return r
+	}
+	SwirlEffect(book.Pages, node.RotationRate.Value)
+	return &object.Null{}
 	case *ast.SaveStatement:
 		val := evalSave(node, env)
 		if isError(val) {
@@ -51,7 +76,7 @@ func Eval(node ast.Node, env *object.Environment) object.Object {
 	return nil
 }
 
-//eval a bunch of statements by passing them to Eval()
+// eval a bunch of statements by passing them to Eval()
 func evalStatements(sts []ast.Statement, env *object.Environment) object.Object {
 	var result object.Object
 
@@ -62,7 +87,7 @@ func evalStatements(sts []ast.Statement, env *object.Environment) object.Object
 	return result
 }
 
-//resolve an identifier
+// resolve an identifier
 func evalIdentifier(node *ast.Identifier, env *object.Environment) object.Object {
 	val, ok := env.Get(node.Value)
 	if ok {
@@ -71,7 +96,7 @@ func evalIdentifier(node *ast.Identifier, env *object.Environment) object.Object
 	return newError("identifier not found: " + node.Value)
 }
 
-//evaluate New type of statements
+// evaluate New type of statements
 func evalNew(inp *ast.NewStatement, env *object.Environment) object.Object {
 	st := *inp
 	if st.DType.Value == "image" {
@@ -89,7 +114,7 @@ func evalNew(inp *ast.NewStatement, env *object.Environment) object.Object {
 	return &object.Null{}
 }
 
-//evaluate Insert statements
+// evaluate Insert statements
 func evalInsert(inp *ast.InsertStatement, env *object.Environment) object.Object {
 	//env.Print()
 	r := evalIdentifier(inp.Image, env)
@@ -125,7 +150,7 @@ func evalInsert(inp *ast.InsertStatement, env *object.Environment) object.Object
 	return &object.Null{}
 }
 
-//evaluate keyframe statements
+// evaluate keyframe statements
 func evalKeyframe(inp *ast.KeyframeStatement, env *object.Environment) object.Object {
 	r := evalIdentifier(inp.Image, env)
 	img, ok := r.(*object.Image)
@@ -177,11 +202,30 @@ func evalKeyframe(inp *ast.KeyframeStatement, env *object.Environment) object.Ob
 }
 
 func evalSave(inp *ast.SaveStatement, env *object.Environment) object.Object {
+	ix := 0
+	iy := 0
 	r := evalIdentifier(inp.Book, env)
 	book, ok := r.(*object.Book)
 	if !ok {
 		return r
 	}
+	imgObj := evalIdentifier(inp.Image, env)
+	img, ok := imgObj.(*object.Image)
+	if !ok {
+		return imgObj
+	}
+	pdf = gopdf.GoPdf{}
+	pdf.Start(gopdf.Config{PageSize: gopdf.Rect{W: float64(book.DimX), H: float64(book.DimY)}})
+	for pno, page := range book.Pages {
+		pdf.AddPage()
+		for _, img := range page.ImagesProps {
+			rotatedImg := img.Image
+			pdf.Image(rotatedImg, float64(ix), float64(iy), nil)
+		}
+	}
+	if !ok {
+		return r
+	}
 	fname := inp.OutputName.Value
 	pw := book.DimX
 	ph := book.DimY
@@ -192,7 +236,7 @@ func evalSave(inp *ast.SaveStatement, env *object.Environment) object.Object {
 	for pno, page := range book.Pages {
 		pdf.AddPage()
 		for _, img := range page.ImagesProps {
-			imgpath := img.Image.Filename
+			imgpath := img.Filename
 			//// TODO: implement scale property change by using a better library for pdf
 			/*iw := int(img.Image.DimX * (0))
 			ih := int(img.Image.DimX * (0))
@@ -201,8 +245,8 @@ func evalSave(inp *ast.SaveStatement, env *object.Environment) object.Object {
 				println("ERROR1")
 				return newError("Image " + fname + " size larger than the page " + strconv.Itoa(pno))
 			}*/
-			ix := img.PosX
-			iy := img.PosY
+			ix = img.PosX
+			iy = img.PosY
 			if (ix > pw) || (iy > ph) {
 				return newError("Image " + fname + " position beyond the page " + strconv.Itoa(pno))
 			}
@@ -215,7 +259,7 @@ func evalSave(inp *ast.SaveStatement, env *object.Environment) object.Object {
 	return &object.Null{}
 }
 
-//Helper Functions
+// Helper Functions
 func isError(obj object.Object) bool {
 	if obj != nil {
 		return obj.Type() == object.ERROR_OBJ

evaluator/evaluator_test.go

@@ -0,0 +1,47 @@
+package evaluator
+
+import (
+	"testing"
+
+	"github.com/Krishanu230/Flipbook-Language/ast"
+	"github.com/Krishanu230/Flipbook-Language/object"
+)
+
+func TestSwirlEffect(t *testing.T) {
+	pages := []object.PageProperty{
+		{ImagesProps: []object.ImageProperty{{Image: object.Image{Rotation: 0}}}},
+		{ImagesProps: []object.ImageProperty{{Image: object.Image{Rotation: 0}}}},
+	}
+	SwirlEffect(pages, 10)
+	if pages[0].ImagesProps[0].Image.Rotation != 0 || pages[1].ImagesProps[0].Image.Rotation != 10 {
+		t.Errorf("SwirlEffect did not correctly update the rotation of the images")
+	}
+}
+
+func TestEvalSwirlEffect(t *testing.T) {
+	env := object.NewEnvironment()
+	env.Set("bookone", &object.Book{Pages: []object.PageProperty{
+		{ImagesProps: []object.ImageProperty{{Image: object.Image{Rotation: 0}}}},
+		{ImagesProps: []object.ImageProperty{{Image: object.Image{Rotation: 0}}}},
+	}})
+	node := &ast.SwirlEffectStatement{Book: &ast.Identifier{Value: "bookone"}, RotationRate: &ast.IntegerLiteral{Value: 10}}
+	evalSwirlEffect(node, env)
+	book, _ := env.Get("bookone")
+	if book.(*object.Book).Pages[0].ImagesProps[0].Image.Rotation != 0 || book.(*object.Book).Pages[1].ImagesProps[0].Image.Rotation != 10 {
+		t.Errorf("evalSwirlEffect did not correctly update the rotation of the images")
+	}
+}
+
+func TestEvalSave(t *testing.T) {
+	env := object.NewEnvironment()
+	env.Set("bookone", &object.Book{Pages: []object.PageProperty{
+		{ImagesProps: []object.ImageProperty{{Image: object.Image{Rotation: 0}}}},
+		{ImagesProps: []object.ImageProperty{{Image: object.Image{Rotation: 0}}}},
+	}})
+	node := &ast.SaveStatement{Book: &ast.Identifier{Value: "bookone"}, OutputName: &ast.StringLiteral{Value: "out.pdf"}}
+	evalSave(node, env)
+	book, _ := env.Get("bookone")
+	if book.(*object.Book).Pages[0].ImagesProps[0].Image.Rotation != 0 || book.(*object.Book).Pages[1].ImagesProps[0].Image.Rotation != 10 {
+		t.Errorf("evalSave did not correctly update the rotation of the images")
+	}
+}

lexer/lexer_test.go

@@ -41,6 +41,10 @@ func TestNextToken(t *testing.T) {
 		{token.SCALE, "scale"},
 		{token.INT, "10"},
 		{token.SEMICOLON, ";"},
+		{token.SWIRL, "swirl"},
+		{token.IDN, "bookone"},
+		{token.INT, "10"},
+		{token.SEMICOLON, ";"},
 	}
 
 	l := NewLexer(input)