Fix values

cli/main.go

@@ -147,7 +147,7 @@ func (cmd *RunCmd) Run(ctx *Context) error {
 		log.Println("=v= output =v=")
 	}
 	// execute order 66
-	for vm.HasNext() && vm.Next() {
+	for vm.Next() {
 	}
 
 	return nil

core/all_test.go

@@ -16,7 +16,7 @@ func GetAllTestCases() map[string]AllTestCase {
 			[]Value{
 				&VariableValue{
 					"a",
-					NumberValue(1),
+					&NumberValue{1},
 					0,
 				},
 			},
@@ -26,7 +26,7 @@ func GetAllTestCases() map[string]AllTestCase {
 			[]Value{
 				&VariableValue{
 					"sum",
-					FunctionValue{
+					&FunctionValue{
 						Name:   "sum",
 						Params: []string{"a", "b"},
 						Chunk: &Chunk{
@@ -38,7 +38,7 @@ func GetAllTestCases() map[string]AllTestCase {
 								InstructionReturn,
 								InstructionAscend,
 							},
-							Constants: []Value{StringValue("a"), StringValue("b")},
+							Constants: []Value{&StringValue{"a"}, &StringValue{"b"}},
 						},
 					},
 					0,
@@ -86,7 +86,7 @@ func TestAll(t *testing.T) {
 			vm := NewVM(c.Chunk, 256, 256)
 
 			t.Log("Running bytecode")
-			for vm.HasNext() && vm.Next() {
+			for vm.Next() {
 			}
 
 			t.Log("Comparing stacks")
@@ -112,7 +112,7 @@ func BenchmarkAll(b *testing.B) {
 
 				vm := NewVM(c.Chunk, 256, 256)
 
-				for vm.HasNext() && vm.Next() {
+				for vm.Next() {
 				}
 			}
 		})

core/compiler.go

@@ -1,5 +1,9 @@
 package core
 
+import (
+	"fmt"
+)
+
 type Compiler struct {
 	Chunk *Chunk
 	ip    Pos
@@ -45,7 +49,7 @@ func (c *Compiler) add(instruction Bytecode) {
 func (c *Compiler) addConstant(value Value) {
 	chunk := c.Chunk
 	for i := 0; i < len(chunk.Constants); i++ {
-		if chunk.Constants[i] == value {
+		if chunk.Constants[i].Equals(value) {
 			c.add(Bytecode(i))
 
 			return
@@ -57,26 +61,41 @@ func (c *Compiler) addConstant(value Value) {
 	c.add(Bytecode(len(chunk.Constants) - 1))
 }
 
-func (c *Compiler) Compile(tree Node) {
+func (c *Compiler) Compile(tree Node) error {
 	if tree == nil {
-		panic("nil value parse tree node")
+		panic("compile called with nil value")
 	}
 
 	switch tree.Type() {
 	case StringNodeType:
 		c.add(InstructionConstant)
-		c.addConstant(StringValue(tree.(*StringNode).value))
+		c.addConstant(&StringValue{
+			tree.(*StringNode).value,
+		})
 
 	case NumberNodeType:
 		c.add(InstructionConstant)
-		c.addConstant(tree.(*NumberNode).value)
+		c.addConstant(&NumberValue{tree.(*NumberNode).value})
 
 	case ListNodeType:
-		v := tree.(*ListNode).items
+		l := tree.(*ListNode)
+
+		if len(l.items) == 0 {
 			c.add(InstructionNewList)
-		for _, n := range v {
+		} else if c.isTreeConstant(l) {
+			v, err := c.compute(l)
+			if err != nil {
+				panic(err) // this shouldn't happen
+			}
+
+			c.add(InstructionConstant)
+			c.addConstant(v)
+		} else {
+			for _, n := range l.items {
 				c.Compile(n)
-			c.add(InstructionAppend)
+			}
+			c.add(InstructionFormList)
+			c.addU16(uint16(len(l.items)))
 		}
 
 	case ReferenceNodeType:
@@ -201,12 +220,17 @@ func (c *Compiler) Compile(tree Node) {
 		for _, p := range n.params {
 			c.registerVar(p)
 		}
-		c.Compile(n.logic)
+
+		err := c.Compile(n.logic)
+		if err != nil {
+			return err
+		}
+
 		if n.logic.Type() != BlockNodeType {
 			c.stack.Pop()
 		}
 
-		mc.Constants[fi] = FunctionValue{
+		mc.Constants[fi] = &FunctionValue{
 			n.name,
 			n.params,
 			c.Chunk,
@@ -219,9 +243,14 @@ func (c *Compiler) Compile(tree Node) {
 
 	case AccessNodeType:
 		n := tree.(*AccessNode)
-		c.Compile(n.source)
+		err := c.Compile(n.source)
+		if err != nil {
+			return err
+		}
 		c.add(InstructionAccessProperty)
-		c.addConstant(StringValue(n.property))
+		c.addConstant(&StringValue{
+			n.property,
+		})
 
 	case ImportNodeType:
 		n := tree.(*ImportNode)
@@ -229,21 +258,46 @@ func (c *Compiler) Compile(tree Node) {
 		t := c.resolveImport(n.path).(*BlockNode)
 
 		for _, statement := range t.statements {
-			c.Compile(statement)
+			err := c.Compile(statement)
+			if err != nil {
+				return err
+			}
 		}
 
 	case ReturnNodeType:
-		c.Compile(tree.(*ReturnNode).value)
+		err := c.Compile(tree.(*ReturnNode).value)
+		if err != nil {
+			return err
+		}
 		c.add(InstructionReturn)
 
 	case BreakpointNodeType:
 		c.add(InstructionBreakpoint)
 	}
+
+	return nil
 }
 
-func (c *Compiler) compileBinary(binary *BinaryNode) {
+func (c *Compiler) compileBinary(binary *BinaryNode) error {
-	c.Compile(binary.Left)
+	if c.isTreeConstant(binary) {
-	c.Compile(binary.Right)
+		v, err := c.compute(binary)
+		if err != nil {
+			return err
+		}
+
+		c.add(InstructionConstant)
+		c.addConstant(v)
+		return nil
+	}
+
+	err := c.Compile(binary.Left)
+	if err != nil {
+		return err
+	}
+	err = c.Compile(binary.Right)
+	if err != nil {
+		return err
+	}
 
 	switch binary.BinaryOperation {
 	case BinaryAddition:
@@ -271,20 +325,29 @@ func (c *Compiler) compileBinary(binary *BinaryNode) {
 	case BinaryOr:
 		c.add(InstructionOr)
 	}
+
+	return nil
 }
 
 func (c *Compiler) getVar(name string) {
 	if c.isGlobal(name) {
 		c.add(InstructionGetGlobal)
-		c.addConstant(StringValue(name))
+		c.addConstant(&StringValue{
+			name,
+		})
 	} else {
 		c.add(InstructionGetLocal)
-		c.addConstant(StringValue(name))
+		c.addConstant(&StringValue{
+			name,
+		})
 	}
 }
 
-func (c *Compiler) setVar(name string, value Node, declare bool) {
+func (c *Compiler) setVar(name string, value Node, declare bool) error {
-	c.Compile(value)
+	err := c.Compile(value)
+	if err != nil {
+		return err
+	}
 
 	if declare {
 		c.add(InstructionDeclareLocal)
@@ -293,7 +356,11 @@ func (c *Compiler) setVar(name string, value Node, declare bool) {
 		c.add(InstructionSetLocal)
 	}
 
-	c.addConstant(StringValue(name))
+	c.addConstant(&StringValue{
+		name,
+	})
+
+	return nil
 }
 
 // keep track that a variable is declared but doesn't necessarily have a deducible type
@@ -314,6 +381,112 @@ func (c *Compiler) isLocal(name string) bool {
 	return false
 }
 
+// isTreeConstant check if a node tree is constant (predictable)
+func (c *Compiler) isTreeConstant(tree Node) bool {
+	switch tree.Type() {
+	case StringNodeType, NumberNodeType, BooleanNodeType, NilNodeType:
+		return true
+	case ListNodeType:
+		for _, item := range tree.(*ListNode).items {
+			if !c.isTreeConstant(item) {
+				return false
+			}
+		}
+
+		return true
+	case BinaryNodeType:
+		return c.isTreeConstant(tree.(*BinaryNode).Left) && c.isTreeConstant(tree.(*BinaryNode).Right)
+	case BlockNodeType, ConditionalNodeType, LoopNodeType, AssignNodeType, CallNodeType, FunctionNodeType,
+		ReturnNodeType, AccessNodeType, BreakpointNodeType, ImportNodeType, ReferenceNodeType:
+		return false
+	default:
+		panic(fmt.Sprintf("unexpected node %s", tree))
+	}
+}
+
+func (c *Compiler) compute(tree Node) (Value, error) {
+	switch n := tree.(type) {
+	case *StringNode:
+		return &StringValue{
+			n.value,
+		}, nil
+
+	case *NumberNode:
+		return &NumberValue{
+			n.value,
+		}, nil
+
+	case *BooleanNode:
+		return &BoolValue{
+			n.value,
+		}, nil
+
+	case *NilNode:
+		return &NilValue{}, nil
+
+	case *ListNode:
+		items := make([]Value, len(n.items))
+		var err error
+		for i, item := range n.items {
+			items[i], err = c.compute(item)
+
+			if err != nil {
+				return nil, err
+			}
+		}
+		return &ListValue{
+			items,
+		}, nil
+
+	case *BinaryNode:
+		return c.computeBinary(n)
+
+	default:
+		panic(fmt.Sprintf("unexpected node %s, %T", tree.String(), tree))
+	}
+}
+
+func (c *Compiler) computeBinary(n *BinaryNode) (Value, error) {
+	l, err := c.compute(n.Left)
+	if err != nil {
+		return nil, err
+	}
+	r, err := c.compute(n.Right)
+	if err != nil {
+		return nil, err
+	}
+
+	var v interface{}
+	switch n.BinaryOperation {
+	case BinaryAddition:
+		v = l.(*NumberValue).float64 + r.(*NumberValue).float64
+	case BinarySubtraction:
+		v = l.(*NumberValue).float64 - r.(*NumberValue).float64
+	case BinaryMultiplication:
+		v = l.(*NumberValue).float64 * r.(*NumberValue).float64
+	case BinaryDivision:
+		v = l.(*NumberValue).float64 / r.(*NumberValue).float64
+	case BinaryAnd:
+		v = l.(*BoolValue).bool && r.(*BoolValue).bool
+	case BinaryOr:
+		v = l.(*BoolValue).bool && r.(*BoolValue).bool
+	case BinaryEquality:
+		v = l.Equals(r)
+	case BinaryInequality:
+		v = !l.Equals(r.(*BoolValue))
+	case BinaryLess:
+		v = l.(*NumberValue).float64 < r.(*NumberValue).float64
+	case BinaryGreater:
+		v = l.(*NumberValue).float64 > r.(*NumberValue).float64
+	case BinaryLessEqual:
+		v = l.(*NumberValue).float64 <= r.(*NumberValue).float64
+	case BinaryGreaterEqual:
+		v = l.(*NumberValue).float64 >= r.(*NumberValue).float64
+	}
+
+	return GoToValue(v), nil
+}
+
 // isGlobal whether a variable is defined in the standard global environment
 func (c *Compiler) isGlobal(name string) bool {
 	return DefaultGlobals[name] != nil

core/compiler_test.go

@@ -40,7 +40,7 @@ func GetCompileTestData() map[string]CompileTestData {
 				"\"Hello world!\"",
 			},
 			[]Value{
-				StringValue("Hello world!"),
+				&StringValue{"Hello world!"},
 			},
 		},
 		"conditional_false": {
@@ -75,7 +75,7 @@ func GetCompileTestData() map[string]CompileTestData {
 			[]Value{
 				&VariableValue{
 					"a",
-					NumberValue(0),
+					&NumberValue{0},
 					0,
 				},
 			},
@@ -112,7 +112,7 @@ func GetCompileTestData() map[string]CompileTestData {
 			[]Value{
 				&VariableValue{
 					"a",
-					NumberValue(1),
+					&NumberValue{1},
 					0,
 				},
 			},
@@ -159,7 +159,7 @@ func GetCompileTestData() map[string]CompileTestData {
 			[]Value{
 				&VariableValue{
 					"a",
-					NumberValue(2),
+					&NumberValue{2},
 					0,
 				},
 			},
@@ -206,7 +206,7 @@ func GetCompileTestData() map[string]CompileTestData {
 			[]Value{
 				&VariableValue{
 					"a",
-					NumberValue(1),
+					&NumberValue{1},
 					0,
 				},
 			},
@@ -222,7 +222,7 @@ func GetCompileTestData() map[string]CompileTestData {
 				},
 			},
 			[]Value{
-				NumberValue(3),
+				&NumberValue{3},
 			},
 		},
 		"sum_function": {&BlockNode{
@@ -251,7 +251,8 @@ func GetCompileTestData() map[string]CompileTestData {
 			[]Value{
 				&VariableValue{
 					"sum",
-					FunctionValue{
+
+					&FunctionValue{
 						"sum",
 						[]string{"a", "b"},
 						NewChunk(
@@ -264,7 +265,7 @@ func GetCompileTestData() map[string]CompileTestData {
 								InstructionAscend,
 							},
 							[]Value{
-								StringValue("a"), StringValue("b"),
+								&StringValue{"a"}, &StringValue{"b"},
 							},
 						),
 						nil,
@@ -308,7 +309,7 @@ func GetCompileTestData() map[string]CompileTestData {
 			[]Value{
 				&VariableValue{
 					"a",
-					FunctionValue{
+					&FunctionValue{
 						"a",
 						[]string{},
 						NewChunk(
@@ -321,7 +322,7 @@ func GetCompileTestData() map[string]CompileTestData {
 								InstructionAscend,
 							},
 							[]Value{
-								NumberValue(1), StringValue("b"),
+								&NumberValue{1}, &StringValue{"b"},
 							},
 						),
 						nil,
@@ -344,7 +345,7 @@ func printChunk(t *testing.T, name string, chunk *Chunk) {
 	for i, ct := range chunk.Constants {
 		t.Logf("c=%d \t%s", i, ct)
 
-		f, ok := ct.(FunctionValue)
+		f, ok := ct.(*FunctionValue)
 		if ok {
 			printChunk(t, f.Name, f.Chunk)
 		}
@@ -371,7 +372,7 @@ func TestCompile(t *testing.T) {
 			printChunk(t, name, c.Chunk)
 
 			t.Log("Executing bytecode")
-			for vm.HasNext() && vm.Next() {
+			for vm.Next() {
 			}
 			t.Log("Executed bytecode")
 
@@ -437,7 +438,7 @@ func TestCompiler_CleanStack(t *testing.T) {
 			c.Compile(tc.tree)
 
 			vm := NewVM(c.Chunk, 256, 256)
-			for vm.HasNext() && vm.Next() {
+			for vm.Next() {
 			}
 
 			// make sure stack has only assigned values

core/lexer.go

@@ -151,6 +151,8 @@ func (t TokenType) String() string {
 		return "open bracket"
 	case TokenCloseBracket:
 		return "close bracket"
+	case TokenImport:
+		return "import"
 	}
 
 	return "UNDEFINED TOKENTYPE STRING CONVERSION"

core/nodes.go

@@ -101,7 +101,7 @@ func (n StringNode) String() string {
 }
 
 type NumberNode struct {
-	value NumberValue
+	value float64
 }
 
 func (n NumberNode) Type() NodeType {
@@ -109,7 +109,7 @@ func (n NumberNode) Type() NodeType {
 }
 
 func (n NumberNode) String() string {
-	return strconv.FormatFloat(float64(n.value), 'g', -1, NumberSize)
+	return strconv.FormatFloat(n.value, 'g', -1, NumberSize)
 }
 
 // ListNode a list or sequence of values (items)

core/parser.go

@@ -158,7 +158,7 @@ func (p *Parser) factor() (Node, error) {
 		}
 
 		return &NumberNode{
-			NumberValue(num),
+			num,
 		}, nil
 
 	case TokenTrue:
@@ -209,7 +209,7 @@ func (p *Parser) factor() (Node, error) {
 		}
 		return &BinaryNode{
 			BinarySubtraction,
-			&NumberNode{NumberValue(0)},
+			&NumberNode{0},
 			f,
 		}, nil
 

core/parser_test.go

@@ -65,10 +65,10 @@ func GetTokenTestData() map[string]TokenTestData {
 						&BinaryNode{
 							BinaryAddition,
 							&NumberNode{
-								value: NumberValue(1),
+								1,
 							},
 							&NumberNode{
-								value: NumberValue(2),
+								2,
 							},
 						},
 						false,
@@ -170,22 +170,22 @@ func GetTokenTestData() map[string]TokenTestData {
 										&NumberNode{2},
 										&NumberNode{1},
 									},
-									&NumberNode{NumberValue(5)},
+									&NumberNode{5},
 								},
 								&BinaryNode{
 									BinaryDivision,
-									&NumberNode{NumberValue(3)},
+									&NumberNode{3},
 									&BinaryNode{
 										BinarySubtraction,
-										&NumberNode{NumberValue(6)},
+										&NumberNode{6},
-										&NumberNode{NumberValue(2)},
+										&NumberNode{2},
 									},
 								},
 							},
 							&BinaryNode{
 								BinaryDivision,
-								&NumberNode{NumberValue(10)},
+								&NumberNode{10},
-								&NumberNode{NumberValue(2)},
+								&NumberNode{2},
 							},
 						},
 						false,
@@ -242,7 +242,7 @@ func GetTokenTestData() map[string]TokenTestData {
 								"a",
 							},
 							&NumberNode{
-								NumberValue(0),
+								0,
 							},
 						},
 						do: &BlockNode{
@@ -250,7 +250,7 @@ func GetTokenTestData() map[string]TokenTestData {
 								&AssignNode{
 									"b",
 									&NumberNode{
-										NumberValue(1),
+										1,
 									},
 									false,
 								},
@@ -288,7 +288,7 @@ func GetTokenTestData() map[string]TokenTestData {
 								"a",
 							},
 							&NumberNode{
-								NumberValue(0),
+								0,
 							},
 						},
 						do: &BlockNode{
@@ -296,7 +296,7 @@ func GetTokenTestData() map[string]TokenTestData {
 								&AssignNode{
 									"b",
 									&NumberNode{
-										NumberValue(1),
+										1,
 									},
 									false,
 								},
@@ -307,7 +307,7 @@ func GetTokenTestData() map[string]TokenTestData {
 								&AssignNode{
 									"b",
 									&NumberNode{
-										NumberValue(0),
+										0,
 									},
 									false,
 								},

core/values.go

@@ -4,7 +4,6 @@ import (
 	"errors"
 	"fmt"
 	"reflect"
-	"slices"
 	"strconv"
 	"strings"
 )
@@ -48,24 +47,34 @@ func (v ValueType) String() string {
 	return "undefined"
 }
 
-// GoToValue convert go values to anglais VM-values. Works for some values (nil, bool, float64, string, slices, maps)
+// GoToValue convert go values to anglais VM-values. Works for some values (nil, bool, float64, int, string, slices, maps)
 func GoToValue(gov interface{}) Value {
 	switch v := gov.(type) {
 	case nil:
-		return NilValue{}
+		return &NilValue{}
 	case bool:
-		return BoolValue(v)
+		return &BoolValue{
+			v,
+		}
+	case int:
+		return &NumberValue{
+			float64(v),
+		}
 	case float64:
-		return NumberValue(v)
+		return &NumberValue{
+			v,
+		}
 	case string:
-		return StringValue(v)
+		return &StringValue{
+			v,
+		}
 	case []interface{}:
 		values := make([]Value, len(v))
 		for i, value := range v {
 			values[i] = GoToValue(value)
 		}
 
-		return ListValue{
+		return &ListValue{
 			values,
 		}
 	case map[string]interface{}:
@@ -74,7 +83,7 @@ func GoToValue(gov interface{}) Value {
 			values[key] = GoToValue(value)
 		}
 
-		return ObjectValue{
+		return &ObjectValue{
 			values,
 		}
 	}
@@ -101,49 +110,51 @@ type Value interface {
 
 type NilValue struct{}
 
-func (v NilValue) Type() ValueType {
+func (v *NilValue) Type() ValueType {
 	return NilValueType
 }
 
-func (v NilValue) String() string {
+func (v *NilValue) String() string {
 	return "nil"
 }
 
-func (v NilValue) DebugString() string {
+func (v *NilValue) DebugString() string {
 	return v.String()
 }
 
-func (v NilValue) Equals(other Value) bool {
+func (v *NilValue) Equals(other Value) bool {
 	return other.Type() == NilValueType
 }
 
-func (v NilValue) Get(key string) (Value, error) {
+func (v *NilValue) Get(_ string) (Value, error) {
 	return nil, errors.New("nil has no properties")
 }
 
-type BoolValue bool
+type BoolValue struct {
+	bool
+}
 
-func (v BoolValue) Type() ValueType {
+func (v *BoolValue) Type() ValueType {
 	return BoolValueType
 }
 
-func (v BoolValue) String() string {
+func (v *BoolValue) String() string {
-	if v {
+	if v.bool {
 		return "true"
 	} else {
 		return "false"
 	}
 }
 
-func (v BoolValue) DebugString() string {
+func (v *BoolValue) DebugString() string {
 	return v.String()
 }
 
-func (v BoolValue) Equals(other Value) bool {
+func (v *BoolValue) Equals(other Value) bool {
-	return other.Type() == BoolValueType && bool(other.(BoolValue)) == bool(v)
+	return other.Type() == BoolValueType && other.(*BoolValue).bool == v.bool
 }
 
-func (v BoolValue) Get(key string) (Value, error) {
+func (v *BoolValue) Get(key string) (Value, error) {
 	return nil, errors.New("booleans have no properties")
 }
 
@@ -152,11 +163,11 @@ type ObjectValue struct {
 	members map[string]Value
 }
 
-func (v ObjectValue) Type() ValueType {
+func (v *ObjectValue) Type() ValueType {
 	return ObjectValueType
 }
 
-func (v ObjectValue) String() string {
+func (v *ObjectValue) String() string {
 	out := "{"
 	for key, value := range v.members {
 		if out != "{" {
@@ -170,74 +181,111 @@ func (v ObjectValue) String() string {
 	return out
 }
 
-func (v ObjectValue) DebugString() string {
+func (v *ObjectValue) DebugString() string {
 	return v.String()
 }
 
-func (v ObjectValue) Equals(other Value) bool {
+func (v *ObjectValue) Equals(other Value) bool {
-	// TODO implement object equality check
+	object, ok := other.(*ObjectValue)
+	if !ok {
 		return false
+	}
+
+	for key, value := range v.members {
+		if !object.members[key].Equals(value) {
+			return false
+		}
+	}
+
+	return true
 }
 
-func (v ObjectValue) Get(key string) (Value, error) {
+var ObjectPrototype = map[string]Value{
-	if member := v.members[key]; member == nil {
+	"set": &BuiltinFunctionValue{
-		return nil, errors.New("no property found with name \"" + key + "\"")
+		"set",
-	} else {
+		[]string{"property", "value"},
+		func(vm *VM, _this Value, params map[string]Value) (Value, error) {
+			this := _this.(*ObjectValue)
+
+			p := params["property"]
+			v, ok := params["value"].(*StringValue)
+			if !ok {
+				return nil, errors.New("property is not a string")
+			}
+
+			this.members[v.string] = p
+
+			return &NilValue{}, nil
+		},
+		nil,
+	},
+}
+
+func (v *ObjectValue) Get(key string) (Value, error) {
+	if member, ok := v.members[key]; ok {
 		return member, nil
+	} else if p, ok := ObjectPrototype[key]; ok {
+		return p, nil
+	} else {
+		return nil, errors.New("no property found with name \"" + key + "\"")
 	}
 }
 
 // NumberValue Integer or floating-point values
-type NumberValue float64
+type NumberValue struct {
+	float64
+}
 
 const NumberSize int = 64
 
-func (v NumberValue) Type() ValueType {
+func (v *NumberValue) Type() ValueType {
 	return NumberValueType
 }
 
-func (v NumberValue) String() string {
+func (v *NumberValue) String() string {
-	return strconv.FormatFloat(float64(v), 'g', -1, NumberSize)
+	return strconv.FormatFloat(v.float64, 'g', -1, NumberSize)
 }
 
-func (v NumberValue) DebugString() string {
+func (v *NumberValue) DebugString() string {
 	return v.String()
 }
 
-func (v NumberValue) Equals(other Value) bool {
+func (v *NumberValue) Equals(other Value) bool {
-	return other.Type() == NumberValueType && float64(other.(NumberValue)) == float64(v)
+	return other.Type() == NumberValueType && other.(*NumberValue).float64 == v.float64
 }
 
-func (v NumberValue) Get(key string) (Value, error) {
+func (v *NumberValue) Get(key string) (Value, error) {
 	// TODO maybe add standard functions for number values?
 	return nil, errors.New("numbers have no properties")
 }
 
-type StringValue string
+type StringValue struct {
+	string
+}
 
-func (v StringValue) Type() ValueType {
+func (v *StringValue) Type() ValueType {
 	return StringValueType
 }
 
-func (v StringValue) String() string {
+func (v *StringValue) String() string {
-	return string(v)
+	return v.string
 }
 
-func (v StringValue) DebugString() string {
+func (v *StringValue) DebugString() string {
 	return "\"" + v.String() + "\""
 }
 
-func (v StringValue) Equals(other Value) bool {
+func (v *StringValue) Equals(other Value) bool {
-	return other.Type() == StringValueType && string(other.(StringValue)) == string(v)
+	return other.Type() == StringValueType && other.(*StringValue).string == v.string
 }
 
-var StringPrototype = map[string]BuiltinFunctionValue{
+var StringPrototype = map[string]*BuiltinFunctionValue{
 	"split": {
 		"split",
 		[]string{"seperator"},
 		func(vm *VM, this Value, m map[string]Value) (Value, error) {
-			str := this.(StringValue).String()
+			str := this.(*StringValue).String()
-			sep := m["seperator"].(StringValue).String()
+			sep := m["seperator"].(*StringValue).String()
 
 			var out []string
 			tmp := strings.Builder{}
@@ -256,7 +304,7 @@ var StringPrototype = map[string]BuiltinFunctionValue{
 	},
 }
 
-func (v StringValue) Get(key string) (Value, error) {
+func (v *StringValue) Get(key string) (Value, error) {
 	if prop, ok := StringPrototype[key]; ok {
 		return prop, nil
 	}
@@ -269,11 +317,11 @@ type ListValue struct {
 	items []Value
 }
 
-func (v ListValue) Type() ValueType {
+func (v *ListValue) Type() ValueType {
 	return ListValueType
 }
 
-func (v ListValue) String() string {
+func (v *ListValue) String() string {
 	out := "["
 	for i, item := range v.items {
 		if i != 0 {
@@ -286,23 +334,37 @@ func (v ListValue) String() string {
 	return out
 }
 
-func (v ListValue) DebugString() string {
+func (v *ListValue) DebugString() string {
 	return v.String()
 }
 
-func (v ListValue) Equals(other Value) bool {
+func (v *ListValue) Equals(other Value) bool {
-	return other.Type() == ListValueType &&
+	if other.Type() != ListValueType {
-		slices.Equal(v.items, other.(ListValue).items)
+		return false
+	}
+
+	l := other.(*ListValue)
+
+	if len(v.items) != len(l.items) {
+		return false
+	}
+
+	for i, item := range l.items {
+		if !item.Equals(l.items[i]) {
+			return false
+		}
+	}
+
+	return true
 }
 
-var ListPrototype = map[string]BuiltinFunctionValue{
+var ListPrototype = map[string]*BuiltinFunctionValue{
 	"append": {
 		"append",
 		[]string{"item"},
 		func(_ *VM, this Value, p map[string]Value) (Value, error) {
-			return ListValue{
+			this.(*ListValue).items = append(this.(*ListValue).items, p["item"])
-				append(this.(ListValue).items, p["item"]),
+			return &NilValue{}, nil
-			}, nil
 		},
 		nil,
 	},
@@ -310,8 +372,8 @@ var ListPrototype = map[string]BuiltinFunctionValue{
 		"at",
 		[]string{"index"},
 		func(_ *VM, this Value, p map[string]Value) (Value, error) {
-			index := int(p["index"].(NumberValue))
+			items := this.(*ListValue).items
-			items := this.(ListValue).items
+			index := int(p["index"].(*NumberValue).float64)
 
 			if index >= len(items) {
 				return nil, errors.New(fmt.Sprintf("list index %x out of range", index))
@@ -325,7 +387,7 @@ var ListPrototype = map[string]BuiltinFunctionValue{
 		"length",
 		[]string{},
 		func(_ *VM, this Value, p map[string]Value) (Value, error) {
-			return NumberValue(len(this.(ListValue).items)), nil
+			return GoToValue(len(this.(*ListValue).items)), nil
 		},
 		nil,
 	},
@@ -333,13 +395,13 @@ var ListPrototype = map[string]BuiltinFunctionValue{
 		"map",
 		[]string{"f"},
 		func(vm *VM, value Value, m map[string]Value) (Value, error) {
-			list := value.(ListValue)
+			list := value.(*ListValue)
 
 			v := m["f"]
 			var f Value
-			f, ok := v.(FunctionValue)
+			f, ok := v.(*FunctionValue)
 			if !ok {
-				f, ok = v.(BuiltinFunctionValue)
+				f, ok = v.(*BuiltinFunctionValue)
 
 				if !ok {
 					return nil, errors.New(fmt.Sprintf("not a function to apply: %s", v))
@@ -365,7 +427,7 @@ var ListPrototype = map[string]BuiltinFunctionValue{
 		"reduce",
 		[]string{"f", "start"},
 		func(vm *VM, value Value, m map[string]Value) (Value, error) {
-			list := value.(ListValue)
+			list := value.(*ListValue)
 			f := m["f"]
 			sum := m["start"]
 
@@ -383,7 +445,7 @@ var ListPrototype = map[string]BuiltinFunctionValue{
 	},
 }
 
-func (v ListValue) Get(key string) (Value, error) {
+func (v *ListValue) Get(key string) (Value, error) {
 	if prop, ok := ListPrototype[key]; ok {
 		return prop, nil
 	}
@@ -398,25 +460,25 @@ type FunctionValue struct {
 	Parent Value
 }
 
-func (v FunctionValue) Type() ValueType {
+func (v *FunctionValue) Type() ValueType {
 	return FunctionValueType
 }
 
-func (v FunctionValue) String() string {
+func (v *FunctionValue) String() string {
 	return fmt.Sprintf("<function name=%s>", v.Name)
 }
 
-func (v FunctionValue) DebugString() string {
+func (v *FunctionValue) DebugString() string {
 	return v.String()
 }
 
-func (v FunctionValue) Equals(other Value) bool {
+func (v *FunctionValue) Equals(other Value) bool {
 	return other.Type() == FunctionValueType &&
-		v.Name == other.(FunctionValue).Name &&
+		v.Name == other.(*FunctionValue).Name &&
-		v.Chunk == other.(FunctionValue).Chunk
+		v.Chunk == other.(*FunctionValue).Chunk
 }
 
-func (v FunctionValue) Get(_ string) (Value, error) {
+func (v *FunctionValue) Get(_ string) (Value, error) {
 	return nil, errors.New("functions have no properties")
 }
 
@@ -431,20 +493,20 @@ func (v BuiltinFunctionValue) Type() ValueType {
 	return BuiltinFunctionValueType
 }
 
-func (v BuiltinFunctionValue) String() string {
+func (v *BuiltinFunctionValue) String() string {
 	return fmt.Sprintf("<function name=%s builtin>", v.Name)
 }
 
-func (v BuiltinFunctionValue) DebugString() string {
+func (v *BuiltinFunctionValue) DebugString() string {
 	return v.String()
 }
 
-func (v BuiltinFunctionValue) Equals(other Value) bool {
+func (v *BuiltinFunctionValue) Equals(other Value) bool {
 	return other.Type() == BuiltinFunctionValueType &&
-		v.Name == other.(BuiltinFunctionValue).Name
+		v.Name == other.(*BuiltinFunctionValue).Name
 }
 
-func (v BuiltinFunctionValue) Get(_ string) (Value, error) {
+func (v *BuiltinFunctionValue) Get(_ string) (Value, error) {
 	return nil, errors.New("functions have no properties")
 }
 
@@ -455,27 +517,27 @@ type VariableValue struct {
 	scope Pos
 }
 
-func (v VariableValue) Type() ValueType {
+func (v *VariableValue) Type() ValueType {
 	return VariableValueType
 }
 
-func (v VariableValue) String() string {
+func (v *VariableValue) String() string {
 	return fmt.Sprintf("<variable name=%s value=%s scope=%d>", v.name, v.value, v.scope)
 
 	// variables should not be accessed on the stack; normal values should be pushed and popped predictably
 	//panic("tried getting string value of a unreachable value")
 }
 
-func (v VariableValue) DebugString() string {
+func (v *VariableValue) DebugString() string {
 	return v.String()
 }
 
-func (v VariableValue) Equals(other Value) bool {
+func (v *VariableValue) Equals(other Value) bool {
 	return other.Type() == VariableValueType &&
-		v.name == other.(VariableValue).name &&
+		v.name == other.(*VariableValue).name &&
-		v.value.Equals(other.(VariableValue).value)
+		v.value.Equals(other.(*VariableValue).value)
 }
 
-func (v VariableValue) Get(_ string) (Value, error) {
+func (v *VariableValue) Get(_ string) (Value, error) {
 	return nil, errors.New("variables have no properties")
 }

core/values_test.go

@@ -16,26 +16,26 @@ func CompareValues(t *testing.T, got Value, want Value) {
 		t.Logf("Both are nil")
 		return
 	case BoolValueType:
-		if got.(BoolValue) != want.(BoolValue) {
+		if got.(*BoolValue).bool != want.(*BoolValue).bool {
-			t.Errorf("bool value mismatch: got %v, want %v", got.(BoolValue), want.(BoolValue))
+			t.Errorf("bool value mismatch: got %v, want %v", got.(*BoolValue), want.(*BoolValue))
 		} else {
-			t.Logf("Both are same boolean (%s)", want.(BoolValue).String())
+			t.Logf("Both are same boolean (%s)", want.(*BoolValue).String())
 		}
 	case NumberValueType:
-		if got.(NumberValue) != want.(NumberValue) {
+		if got.(*NumberValue).float64 != want.(*NumberValue).float64 {
-			t.Errorf("number value mismatch: got %v, want %v", got.(NumberValue), want.(NumberValue))
+			t.Errorf("number value mismatch: got %v, want %v", got.(*NumberValue), want.(*NumberValue))
 		} else {
-			t.Logf("Both are same number (%s)", got.(NumberValue).String())
+			t.Logf("Both are same number (%s)", got.(*NumberValue).String())
 		}
 	case StringValueType:
-		if got.(StringValue) != want.(StringValue) {
+		if got.(*StringValue).string != want.(*StringValue).string {
-			t.Errorf("string value mismatch: got %v, want %v", got.(StringValue), want.(StringValue))
+			t.Errorf("string value mismatch: got %v, want %v", got.(*StringValue), want.(*StringValue))
 		} else {
-			t.Logf("Both are same string (%s)", got.(StringValue).String())
+			t.Logf("Both are same string (%s)", got.(*StringValue).String())
 		}
 	case FunctionValueType:
-		n := got.(FunctionValue)
+		n := got.(*FunctionValue)
-		m := want.(FunctionValue)
+		m := want.(*FunctionValue)
 
 		if n.Name != m.Name {
 			t.Errorf("function name mismatch: got %v, want %v", n.Name, m.Name)
@@ -53,8 +53,8 @@ func CompareValues(t *testing.T, got Value, want Value) {
 
 		CompareChunks(t, n.Chunk, m.Chunk)
 	case BuiltinFunctionValueType:
-		n := got.(BuiltinFunctionValue)
+		n := got.(*BuiltinFunctionValue)
-		m := want.(BuiltinFunctionValue)
+		m := want.(*BuiltinFunctionValue)
 
 		if n.Name != m.Name {
 			t.Errorf("builtin function name mismatch: got %v, want %v", n.Name, m.Name)

core/vm.go

@@ -96,7 +96,8 @@ const (
 	// InstructionAppend Append to a list. stack: (... > list > item) => (... > list)
 	InstructionAppend
 	// InstructionFormList Form items on the stack into a list. The 2 bytes after the instructions are the amount of
-	// items to include minus one. (value of 0 => 1 item, value of 1 => 2 items, etc.)
+	// items to include minus one. (value of 0 => 1 item, value of 1 => 2 items, etc.) The order is reversed compared
+	// to on the stack; the top value on the stack is the last in the list.
 	InstructionFormList
 
 	// InstructionBreakpoint for debugging purposes
@@ -203,7 +204,7 @@ func (c Chunk) String() string {
 	for i, ct := range c.Constants {
 		b.WriteString(fmt.Sprintf("c=%d \t%s\n", i, ct))
 
-		f, ok := ct.(FunctionValue)
+		f, ok := ct.(*FunctionValue)
 		if ok {
 			b.WriteString(f.Chunk.String())
 		}
@@ -219,9 +220,10 @@ func NewChunk(bytecode []Bytecode, constants []Value) *Chunk {
 }
 
 func RegisterGOBTypes() {
-	gob.Register(StringValue(""))
+	gob.Register(&StringValue{""})
-	gob.Register(NumberValue(0))
+	gob.Register(&BoolValue{false})
-	gob.Register(FunctionValue{
+	gob.Register(&NumberValue{0})
+	gob.Register(&FunctionValue{
 		Name:   "",
 		Params: nil,
 		Chunk:  nil,
@@ -283,7 +285,7 @@ type Call struct {
 }
 
 var DefaultGlobals = map[string]Value{
-	"write": BuiltinFunctionValue{
+	"write": &BuiltinFunctionValue{
 		"write", // always remember where you come from...
 		[]string{"value"},
 		func(_ *VM, this Value, v map[string]Value) (Value, error) {
@@ -292,7 +294,7 @@ var DefaultGlobals = map[string]Value{
 		},
 		nil,
 	},
-	"print": BuiltinFunctionValue{
+	"print": &BuiltinFunctionValue{
 		"print",
 		[]string{"value"},
 		func(_ *VM, this Value, v map[string]Value) (Value, error) {
@@ -301,15 +303,43 @@ var DefaultGlobals = map[string]Value{
 		},
 		nil,
 	},
-	"assert": BuiltinFunctionValue{
+	"format": &BuiltinFunctionValue{
-		"assert",
+		"format",
-		[]string{"condition"},
+		[]string{"format_string", "values"},
+		func(vm *VM, value Value, m map[string]Value) (Value, error) {
+			valuies := m["values"].(*ListValue).items
+
+			return GoToValue(fmt.Sprintf(m["format_string"].String(), valuies)), nil
+		},
+		nil,
+	},
+	"assertEq": &BuiltinFunctionValue{
+		"assertEq",
+		[]string{"a", "b"},
 		func(vm *VM, this Value, params map[string]Value) (Value, error) {
-			if !params["condition"].(BoolValue) {
+			a := params["a"]
-				return nil, errors.New("assertion failed")
+			b := params["b"]
+
+			if !a.Equals(b) {
+				return nil, errors.New(fmt.Sprintf("assertion failed: %s does not equal %s", a, b))
 			}
 
-			return NilValue{}, nil
+			return &NilValue{}, nil
+		},
+		nil,
+	},
+	"assertNotEq": &BuiltinFunctionValue{
+		"assertNotEq",
+		[]string{"a", "b"},
+		func(vm *VM, this Value, params map[string]Value) (Value, error) {
+			a := params["a"]
+			b := params["b"]
+
+			if a.Equals(b) {
+				return nil, errors.New(fmt.Sprintf("assertion failed: %s does not equal %s", a, b))
+			}
+
+			return &NilValue{}, nil
 		},
 		nil,
 	},
@@ -330,6 +360,10 @@ func NewVM(chunk *Chunk, stackSize Pos, callstackSize Pos) *VM {
 // Next execute instruction
 // returns true if more instructions should be executed
 func (vm *VM) Next() bool {
+	if !vm.HasNext() {
+		return false
+	}
+
 	switch vm.NextByte() {
 	case InstructionReturn:
 		if vm.call.Current == 0 {
@@ -359,81 +393,81 @@ func (vm *VM) Next() bool {
 		vm.stack.Push(vm.ReadConstant())
 
 	case InstructionAdd:
-		r := vm.stack.Pop().(NumberValue)
+		r := vm.stack.Pop().(*NumberValue).float64
-		l := vm.stack.Pop().(NumberValue)
+		l := vm.stack.Pop().(*NumberValue).float64
 
-		vm.stack.Push(l + r)
+		vm.stack.Push(&NumberValue{l + r})
 
 	case InstructionSub:
-		r := vm.stack.Pop().(NumberValue)
+		r := vm.stack.Pop().(*NumberValue).float64
-		l := vm.stack.Pop().(NumberValue)
+		l := vm.stack.Pop().(*NumberValue).float64
 
-		vm.stack.Push(l - r)
+		vm.stack.Push(&NumberValue{l - r})
 
 	case InstructionMul:
-		r := vm.stack.Pop().(NumberValue)
+		r := vm.stack.Pop().(*NumberValue).float64
-		l := vm.stack.Pop().(NumberValue)
+		l := vm.stack.Pop().(*NumberValue).float64
 
-		vm.stack.Push(l * r)
+		vm.stack.Push(&NumberValue{l * r})
 
 	case InstructionDiv:
-		r := vm.stack.Pop().(NumberValue)
+		r := vm.stack.Pop().(*NumberValue).float64
-		l := vm.stack.Pop().(NumberValue)
+		l := vm.stack.Pop().(*NumberValue).float64
 
-		vm.stack.Push(l / r)
+		vm.stack.Push(&NumberValue{l / r})
 
 	case InstructionEquals:
 		vm.stack.Push(
-			BoolValue(vm.stack.Pop().Equals(vm.stack.Pop())),
+			&BoolValue{vm.stack.Pop().Equals(vm.stack.Pop())},
 		)
 
 	case InstructionNotEqual:
 		vm.stack.Push(
-			BoolValue(!vm.stack.Pop().Equals(vm.stack.Pop())),
+			&BoolValue{!vm.stack.Pop().Equals(vm.stack.Pop())},
 		)
 
 	case InstructionNot:
-		b := vm.stack.Pop().(BoolValue)
+		b := vm.stack.Pop().(*BoolValue).bool
-		vm.stack.Push(!b)
+		vm.stack.Push(&BoolValue{!b})
 
 	case InstructionAnd:
-		r := vm.stack.Pop().(BoolValue)
+		r := vm.stack.Pop().(*BoolValue).bool
-		l := vm.stack.Pop().(BoolValue)
+		l := vm.stack.Pop().(*BoolValue).bool
-		vm.stack.Push(l && r)
+		vm.stack.Push(&BoolValue{l && r})
 
 	case InstructionOr:
-		r := vm.stack.Pop().(BoolValue)
+		r := vm.stack.Pop().(*BoolValue).bool
-		l := vm.stack.Pop().(BoolValue)
+		l := vm.stack.Pop().(*BoolValue).bool
-		vm.stack.Push(r || l)
+		vm.stack.Push(&BoolValue{l || r})
 
 	case InstructionLess:
-		r := vm.stack.Pop().(NumberValue)
+		r := vm.stack.Pop().(*NumberValue).float64
-		l := vm.stack.Pop().(NumberValue)
+		l := vm.stack.Pop().(*NumberValue).float64
 
-		vm.stack.Push(BoolValue(l < r))
+		vm.stack.Push(&BoolValue{l < r})
 
 	case InstructionLessOrEqual:
-		r := vm.stack.Pop().(NumberValue)
+		r := vm.stack.Pop().(*NumberValue).float64
-		l := vm.stack.Pop().(NumberValue)
+		l := vm.stack.Pop().(*NumberValue).float64
 
-		vm.stack.Push(BoolValue(l <= r))
+		vm.stack.Push(&BoolValue{l <= r})
 
 	case InstructionGreater:
-		r := vm.stack.Pop().(NumberValue)
+		r := vm.stack.Pop().(*NumberValue).float64
-		l := vm.stack.Pop().(NumberValue)
+		l := vm.stack.Pop().(*NumberValue).float64
 
-		vm.stack.Push(BoolValue(l > r))
+		vm.stack.Push(&BoolValue{l > r})
 
 	case InstructionGreaterOrEqual:
-		r := vm.stack.Pop().(NumberValue)
+		r := vm.stack.Pop().(*NumberValue).float64
-		l := vm.stack.Pop().(NumberValue)
+		l := vm.stack.Pop().(*NumberValue).float64
 
-		vm.stack.Push(BoolValue(l >= r))
+		vm.stack.Push(&BoolValue{l >= r})
 
 	case InstructionCall:
 		v := vm.stack.Pop()
 		switch f := v.(type) {
-		case FunctionValue:
+		case *FunctionValue:
 			vm.call.Push(Call{
 				chunk:       vm.chunk,
 				ip:          vm.ip,
@@ -459,7 +493,7 @@ func (vm *VM) Next() bool {
 
 			vm.chunk = f.Chunk
 			vm.ip = 0
-		case BuiltinFunctionValue:
+		case *BuiltinFunctionValue:
 			args := map[string]Value{}
 
 			for i := len(f.Parameters) - 1; i >= 0; i-- {
@@ -473,7 +507,7 @@ func (vm *VM) Next() bool {
 
 			vm.stack.Push(v)
 		default:
-			vm.error(fmt.Sprintf("value called is not a function (%s)", v.DebugString()))
+			vm.error(fmt.Sprintf("value called is not a function (%s, type %T)", v.DebugString(), v))
 			return false
 		}
 
@@ -485,13 +519,13 @@ func (vm *VM) Next() bool {
 
 	case InstructionJumpFalse:
 		n := vm.NextU16()
-		if !vm.stack.Pop().(BoolValue) {
+		if !vm.stack.Pop().(*BoolValue).bool {
 			vm.ip += Pos(n)
 		}
 
 	case InstructionGetLocal:
-		name := vm.GetConstant(vm.NextByte()).(StringValue)
+		name := vm.GetConstant(vm.NextByte()).(*StringValue).string
-		v := vm.getVar(string(name))
+		v := vm.getVar(name)
 
 		if v == nil {
 			vm.error(fmt.Sprintf("cannot get local: undefined variable %s", name))
@@ -502,9 +536,9 @@ func (vm *VM) Next() bool {
 
 	case InstructionSetLocal:
 		value := vm.stack.Pop().(Value)
-		name := vm.GetConstant(vm.NextByte()).(StringValue)
+		name := vm.GetConstant(vm.NextByte()).(*StringValue).string
 
-		v := vm.getVar(string(name))
+		v := vm.getVar(name)
 
 		if v == nil {
 			vm.error(fmt.Sprintf("cannot set local: undefined variable %s", name))
@@ -514,33 +548,39 @@ func (vm *VM) Next() bool {
 
 	case InstructionDeclareLocal:
 		vm.addVar(
-			string(vm.GetConstant(vm.NextByte()).(StringValue)),
+			vm.GetConstant(vm.NextByte()).(*StringValue).string,
 			vm.stack.Pop().(Value),
 		)
 
 	case InstructionGetGlobal:
-		vm.stack.Push(vm.globals[string(vm.GetConstant(vm.NextByte()).(StringValue))])
+		vm.stack.Push(vm.globals[vm.GetConstant(vm.NextByte()).(*StringValue).string])
 
 	case InstructionSetGlobal:
-		vm.globals[string(vm.GetConstant(vm.NextByte()).(StringValue))] = vm.stack.Pop()
+		vm.globals[vm.GetConstant(vm.NextByte()).(*StringValue).string] = vm.stack.Pop()
 
 	case InstructionTrue:
-		vm.stack.Push(BoolValue(true))
+		vm.stack.Push(&BoolValue{true})
 
 	case InstructionFalse:
-		vm.stack.Push(BoolValue(false))
+		vm.stack.Push(&BoolValue{false})
 
 	case InstructionNil:
-		vm.stack.Push(NilValue{})
+		vm.stack.Push(&NilValue{})
 
 	case InstructionFormList:
+		n := int(vm.NextU16())
+
+		items := make([]Value, n+1)
+		for i := 0; i <= n; i++ {
+			items[n-i] = vm.stack.Pop()
+		}
 
 	case InstructionNewList:
-		vm.stack.Push(ListValue{[]Value{}})
+		vm.stack.Push(&ListValue{[]Value{}})
 
 	case InstructionAppend:
 		value := vm.stack.Pop()
-		list := vm.stack.Pop().(ListValue)
+		list := vm.stack.Pop().(*ListValue)
 		list.items = append(list.items, value)
 		vm.stack.Push(list)
 
@@ -552,13 +592,13 @@ func (vm *VM) Next() bool {
 
 	case InstructionStringConversion:
 		v := vm.stack.Pop()
-		vm.stack.Push(StringValue(v.String()))
+		vm.stack.Push(&StringValue{v.String()})
 
 	case InstructionStringConcatenation:
-		r := vm.stack.Pop().(StringValue)
+		r := vm.stack.Pop().(*StringValue).string
-		l := vm.stack.Pop().(StringValue)
+		l := vm.stack.Pop().(*StringValue).string
 
-		vm.stack.Push(l + r)
+		vm.stack.Push(&StringValue{l + r})
 
 	case InstructionSwap:
 		r := vm.stack.Pop()
@@ -570,20 +610,16 @@ func (vm *VM) Next() bool {
 		source := vm.stack.Pop()
 		property := vm.ReadConstant()
 
-		member, err := source.Get(property.(StringValue).String())
+		member, err := source.Get(property.(*StringValue).String())
 		if err != nil {
 			vm.error(err.Error())
 		}
 
-		// add parent if function with a little switcheroo
+		// add parent if function
 		if member.Type() == FunctionValueType {
-			f := member.(FunctionValue)
+			member.(*FunctionValue).Parent = source
-			f.Parent = source
-			member = f
 		} else if member.Type() == BuiltinFunctionValueType {
-			f := member.(BuiltinFunctionValue)
+			member.(*BuiltinFunctionValue).Parent = source
-			f.Parent = source
-			member = f
 		}
 
 		vm.stack.Push(member)
@@ -599,7 +635,7 @@ func (vm *VM) Next() bool {
 
 func (vm *VM) Call(v Value, args []Value) (Value, error) {
 	switch f := v.(type) {
-	case FunctionValue:
+	case *FunctionValue:
 		vm.call.Push(Call{
 			chunk:       vm.chunk,
 			ip:          vm.ip,
@@ -630,7 +666,7 @@ func (vm *VM) Call(v Value, args []Value) (Value, error) {
 
 		return vm.stack.Pop(), nil
 
-	case BuiltinFunctionValue:
+	case *BuiltinFunctionValue:
 		argies := map[string]Value{}
 
 		for i, arg := range args {

core/vm_test.go

@@ -11,7 +11,7 @@ func CompareChunks(t *testing.T, got *Chunk, want *Chunk) {
 	}
 
 	for i, v := range got.Constants {
-		if v != want.Constants[i] {
+		if i < len(want.Constants) && !v.Equals(want.Constants[i]) {
 			t.Errorf("constant %d does not match (%s and %s)", i, v.String(), want.Constants[i].String())
 		}
 	}
@@ -49,7 +49,7 @@ func TestNewVM(t *testing.T) {
 	chunk := NewChunk([]Bytecode{
 		InstructionConstant, 0,
 	}, []Value{
-		NumberValue(0),
+		&NumberValue{0},
 	})
 	stackSize := Pos(256)
 	callstackSize := Pos(256)
@@ -107,10 +107,10 @@ func GetExecutionTestData() map[string]struct {
 				InstructionAdd,
 			},
 				[]Value{
-					NumberValue(1), NumberValue(2),
+					&NumberValue{1}, &NumberValue{2},
 				}),
 			[]Value{
-				NumberValue(3),
+				&NumberValue{3},
 			},
 		},
 		"push_constant": {
@@ -119,11 +119,11 @@ func GetExecutionTestData() map[string]struct {
 					InstructionConstant, 0,
 				},
 				[]Value{
-					NumberValue(1),
+					&NumberValue{1},
 				},
 			),
 			[]Value{
-				NumberValue(1),
+				&NumberValue{1},
 			},
 		},
 		"push_true": {
@@ -134,7 +134,7 @@ func GetExecutionTestData() map[string]struct {
 				[]Value{},
 			),
 			[]Value{
-				BoolValue(true),
+				&BoolValue{true},
 			},
 		},
 		"push_false": {
@@ -145,7 +145,7 @@ func GetExecutionTestData() map[string]struct {
 				[]Value{},
 			),
 			[]Value{
-				BoolValue(false),
+				&BoolValue{false},
 			},
 		},
 		"push_nil": {
@@ -156,7 +156,7 @@ func GetExecutionTestData() map[string]struct {
 				[]Value{},
 			),
 			[]Value{
-				NilValue{},
+				&NilValue{},
 			},
 		},
 		"empty": {
@@ -181,11 +181,11 @@ func GetExecutionTestData() map[string]struct {
 					InstructionDiv,
 				},
 				[]Value{
-					NumberValue(2), NumberValue(1), NumberValue(5), NumberValue(6),
+					&NumberValue{2}, &NumberValue{1}, &NumberValue{5}, &NumberValue{6},
 				},
 			),
 			[]Value{
-				NumberValue((2.0 + 1.0) * 5.0 / (6.0 - 2.0)),
+				&NumberValue{3.75},
 			},
 		},
 		"equality_true": {
@@ -196,11 +196,11 @@ func GetExecutionTestData() map[string]struct {
 					InstructionEquals,
 				},
 				[]Value{
-					NumberValue(1),
+					&NumberValue{1},
 				},
 			),
 			[]Value{
-				BoolValue(true),
+				&BoolValue{true},
 			},
 		},
 		"equality_false": {
@@ -211,11 +211,11 @@ func GetExecutionTestData() map[string]struct {
 					InstructionEquals,
 				},
 				[]Value{
-					NumberValue(1), NumberValue(2),
+					&NumberValue{1}, &NumberValue{2},
 				},
 			),
 			[]Value{
-				BoolValue(false),
+				&BoolValue{false},
 			},
 		},
 		"inequality_false": {
@@ -226,11 +226,11 @@ func GetExecutionTestData() map[string]struct {
 					InstructionNotEqual,
 				},
 				[]Value{
-					NumberValue(1),
+					&NumberValue{1},
 				},
 			),
 			[]Value{
-				BoolValue(false),
+				&BoolValue{false},
 			},
 		},
 		"inequality_true": {
@@ -241,11 +241,11 @@ func GetExecutionTestData() map[string]struct {
 					InstructionNotEqual,
 				},
 				[]Value{
-					NumberValue(1), NumberValue(2),
+					&NumberValue{1}, &NumberValue{2},
 				},
 			),
 			[]Value{
-				BoolValue(true),
+				&BoolValue{true},
 			},
 		},
 		"not_true": {
@@ -257,7 +257,7 @@ func GetExecutionTestData() map[string]struct {
 				[]Value{},
 			),
 			[]Value{
-				BoolValue(false),
+				&BoolValue{false},
 			},
 		},
 		"not_false": {
@@ -269,7 +269,7 @@ func GetExecutionTestData() map[string]struct {
 				[]Value{},
 			),
 			[]Value{
-				BoolValue(true),
+				&BoolValue{true},
 			},
 		},
 		"jump": {
@@ -280,11 +280,11 @@ func GetExecutionTestData() map[string]struct {
 					InstructionConstant, 1, // should execute
 				},
 				[]Value{
-					NumberValue(0), NumberValue(1),
+					&NumberValue{0}, &NumberValue{1},
 				},
 			),
 			[]Value{
-				NumberValue(1),
+				&NumberValue{1},
 			},
 		},
 		"jump_false/false": {
@@ -296,11 +296,11 @@ func GetExecutionTestData() map[string]struct {
 					InstructionConstant, 1, // should execute
 				},
 				[]Value{
-					NumberValue(0), NumberValue(1),
+					&NumberValue{0}, &NumberValue{1},
 				},
 			),
 			[]Value{
-				NumberValue(1),
+				&NumberValue{1},
 			},
 		},
 		"jump_false/true": {
@@ -312,11 +312,11 @@ func GetExecutionTestData() map[string]struct {
 					InstructionConstant, 1, // should execute
 				},
 				[]Value{
-					NumberValue(0), NumberValue(1),
+					&NumberValue{0}, &NumberValue{1},
 				},
 			),
 			[]Value{
-				NumberValue(0), NumberValue(1),
+				&NumberValue{0}, &NumberValue{1},
 			},
 		},
 		"declare_local": {
@@ -326,13 +326,13 @@ func GetExecutionTestData() map[string]struct {
 					InstructionDeclareLocal, 1,
 				},
 				[]Value{
-					NumberValue(0), StringValue("a"),
+					&NumberValue{0}, &StringValue{"a"},
 				},
 			),
 			[]Value{
 				&VariableValue{
 					"a",
-					NumberValue(0),
+					&NumberValue{0},
 					0,
 				},
 			},
@@ -346,13 +346,13 @@ func GetExecutionTestData() map[string]struct {
 					InstructionSetLocal, 1, // reassign
 				},
 				[]Value{
-					NumberValue(0), StringValue("a"), NumberValue(1),
+					&NumberValue{0}, &StringValue{"a"}, &NumberValue{1},
 				},
 			),
 			[]Value{
 				&VariableValue{
 					"a",
-					NumberValue(1),
+					&NumberValue{1},
 					0,
 				},
 			},
@@ -365,16 +365,16 @@ func GetExecutionTestData() map[string]struct {
 					InstructionGetLocal, 1, // reassign
 				},
 				[]Value{
-					NumberValue(0), StringValue("a"),
+					&NumberValue{0}, &StringValue{"a"},
 				},
 			),
 			[]Value{
 				&VariableValue{
 					"a",
-					NumberValue(0),
+					&NumberValue{0},
 					0,
 				},
-				NumberValue(0),
+				&NumberValue{0},
 			},
 		},
 		"get_reassigned_local": {
@@ -388,17 +388,17 @@ func GetExecutionTestData() map[string]struct {
 					InstructionGetLocal, 1,
 				},
 				[]Value{
-					NumberValue(0), StringValue("a"), NumberValue(1),
+					&NumberValue{0}, &StringValue{"a"}, &NumberValue{1},
 				},
 			),
 			[]Value{
 				&VariableValue{
 					"a",
-					NumberValue(1),
+					&NumberValue{1},
 					0,
 				},
-				NumberValue(0),
+				&NumberValue{0},
-				NumberValue(1),
+				&NumberValue{1},
 			},
 		},
 		"variable_scope": {
@@ -416,15 +416,15 @@ func GetExecutionTestData() map[string]struct {
 					InstructionAscend,
 				},
 				[]Value{
-					NumberValue(0), StringValue("a"),
+					&NumberValue{0}, &StringValue{"a"},
-					NumberValue(1), StringValue("b"),
+					&NumberValue{1}, &StringValue{"b"},
-					NumberValue(2), StringValue("c"),
+					&NumberValue{2}, &StringValue{"c"},
 				},
 			),
 			[]Value{
 				&VariableValue{
 					"a",
-					NumberValue(0),
+					&NumberValue{0},
 					0,
 				},
 			},
@@ -438,9 +438,9 @@ func GetExecutionTestData() map[string]struct {
 					InstructionCall,
 				},
 				[]Value{
-					NumberValue(1),
+					&NumberValue{1},
-					NumberValue(2),
+					&NumberValue{2},
-					FunctionValue{
+					&FunctionValue{
 						Name:   "sum",
 						Params: []string{"a", "b"},
 						Chunk: NewChunk(
@@ -451,14 +451,14 @@ func GetExecutionTestData() map[string]struct {
 								InstructionReturn,
 							},
 							[]Value{
-								StringValue("a"), StringValue("b"),
+								&StringValue{"a"}, &StringValue{"b"},
 							},
 						),
 					},
 				},
 			),
 			[]Value{
-				NumberValue(3),
+				&NumberValue{3},
 			},
 		},
 		"function_calling_function": {
@@ -472,9 +472,9 @@ func GetExecutionTestData() map[string]struct {
 					InstructionCall,
 				},
 				[]Value{
-					NumberValue(1),
+					&NumberValue{1},
-					NumberValue(2),
+					&NumberValue{2},
-					FunctionValue{
+					&FunctionValue{
 						Name:   "sum",
 						Params: []string{"a", "b"},
 						Chunk: NewChunk(
@@ -487,11 +487,11 @@ func GetExecutionTestData() map[string]struct {
 								InstructionReturn,
 							},
 							[]Value{
-								StringValue("a"), StringValue("b"), StringValue("square"),
+								&StringValue{"a"}, &StringValue{"b"}, &StringValue{"square"},
 							},
 						),
 					},
-					FunctionValue{
+					&FunctionValue{
 						Name:   "square",
 						Params: []string{"n"},
 						Chunk: NewChunk(
@@ -502,17 +502,17 @@ func GetExecutionTestData() map[string]struct {
 								InstructionReturn,
 							},
 							[]Value{
-								StringValue("n"),
+								&StringValue{"n"},
 							},
 						),
 					},
-					StringValue("square"),
+					&StringValue{"square"},
 				},
 			),
 			[]Value{
 				&VariableValue{
 					"square",
-					FunctionValue{
+					&FunctionValue{
 						Name:   "square",
 						Params: []string{"n"},
 						Chunk: NewChunk(
@@ -523,13 +523,13 @@ func GetExecutionTestData() map[string]struct {
 								InstructionReturn,
 							},
 							[]Value{
-								StringValue("n"),
+								&StringValue{"n"},
 							},
 						),
 					},
 					0,
 				},
-				NumberValue(5),
+				&NumberValue{5},
 			},
 		},
 	}
@@ -542,7 +542,7 @@ func TestVM_Execution(t *testing.T) {
 		t.Run(name, func(t *testing.T) {
 			vm := NewVM(test.chunk, 256, 256)
 
-			for vm.HasNext() && vm.Next() {
+			for vm.Next() {
 			}
 
 			CompareStacks(t, test.resultingStack, vm.stack)
@@ -557,7 +557,7 @@ func BenchmarkVM_Execution(b *testing.B) {
 		b.Run(name, func(b *testing.B) {
 			for n := 0; n < b.N; n++ {
 				vm := NewVM(test.chunk, 256, 256)
-				for vm.HasNext() && vm.Next() {
+				for vm.Next() {
 				}
 			}
 		})
@@ -571,7 +571,7 @@ func TestVM_NextByte(t *testing.T) {
 				InstructionConstant, 0,
 			},
 			[]Value{
-				NumberValue(0),
+				&NumberValue{0},
 			},
 		),
 		16,
@@ -682,7 +682,7 @@ func TestVM_Jump(t *testing.T) {
 				InstructionConstant, 2,
 			},
 			[]Value{
-				NumberValue(0), NumberValue(1), NumberValue(2),
+				&NumberValue{0}, &NumberValue{1}, &NumberValue{2},
 			},
 		),
 		16,
@@ -707,7 +707,7 @@ func TestVM_JumpFalse(t *testing.T) {
 				InstructionConstant, 2,
 			},
 			[]Value{
-				NumberValue(0), NumberValue(1), NumberValue(2),
+				&NumberValue{0}, &NumberValue{1}, &NumberValue{2},
 			},
 		),
 		16,
@@ -733,7 +733,7 @@ func TestVM_DontJumpFalse(t *testing.T) {
 				InstructionConstant, 2,
 			},
 			[]Value{
-				NumberValue(0), NumberValue(1), NumberValue(2),
+				&NumberValue{0}, &NumberValue{1}, &NumberValue{2},
 			},
 		),
 		16,

tests/arithmetics.ang

@@ -1,5 +1,5 @@
-assert(1+1 == 2)
+assertEq(1+1, 2)
-assert(3*2 == 6)
+assertEq(3*2, 6)
-assert(3/4 == 0.75)
+assertEq(3/4, 0.75)
-assert(2 - 5 == -3)
+assertEq(2 - 5, -3)
 

tests/conditions.ang

@@ -1,11 +1,11 @@
 # Basic equality
-assert(1 == 1)
+assertEq(1, 1)
-assert(0 == 0)
+assertEq(0, 0)
-assert("" == "")
+assertEq("", "")
 
-assert([] == [])
+assertEq([], [])
-assert([3, 1, 4, 1] == [3, 1, 4, 1])
+assertEq([3, 1, 4, 1], [3, 1, 4, 1])
-assert([true, 1024, nil, "Hello world!"] == [true, 1024, nil, "Hello world!"])
+assertEq([true, 1024, nil, "Hello world!"], [true, 1024, nil, "Hello world!"])
 
 # Inequality
-assert(2 != 3)
+assertNotEq(2, 3)

tests/list.ang

@@ -2,10 +2,10 @@ list := []
 
 x := 1
 while x <= 1000 {
-    list = list.append(x)
+    list.append(x)
-    assert(list.reduce(func(tot, a){
+    assertEq(list.reduce(func(tot, a){
         return tot + a
-    }, 0) == x*(x + 1)/2)
+    }, 0), x*(x + 1)/2)
 
     x = x + 1
 }
@@ -17,8 +17,8 @@ func sum(a, b) {
 list = []
 x = 1
 while x <= 100 {
-    list = list.append(2*x - 1)
+    list.append(2*x - 1)
-    assert(list.reduce(sum, 0) == x*x)
+    assertEq(list.reduce(sum, 0), x*x)
 
     x = x + 1
 }

tests/recursive_fib.ang

@@ -3,8 +3,7 @@ fibonacci_numbers := [
     0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377,
     610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657,
     46368, 75025, 121393, 196418, 317811, 514229, 832040,
-    1346269, 2178309, 3524578, 5702887, 9227465, 14930352,
+    1346269, 2178309, 3524578, 5702887, 9227465, 14930352
-    24157817, 39088169, 63245986, 102334155
 ]
 
 func fib(n) {
@@ -15,14 +14,21 @@ func fib(n) {
     return fib(n-1) + fib(n-2)
 }
 
+n := 0
+while n < fibonacci_numbers.length() {
+    print("_")
+    n = n + 1
+}
+
+write("")
+
 x := 0
 while x < fibonacci_numbers.length() {
     n := fib(x)
 
-    print("assert ")
+    assertEq(n, fibonacci_numbers.at(x))
-    print(n)
+    print("*")
-    print(" == ")
-    write(fibonacci_numbers.at(x))
-    assert(n == fibonacci_numbers.at(x))
     x = x + 1
 }
+
+write("")

tests/scope.ang

@@ -3,10 +3,10 @@ a := 2
 
 {
     a := 3
-    assert(a == 3)
+    assertEq(a, 3)
 
     a = 4
-    assert(a == 4)
+    assertEq(a, 4)
 }
 
-assert(a == 2)
+assertEq(a, 2)

tests/simple_func.ang

@@ -5,8 +5,8 @@ func sum(a, b) {
 
 breakpoint
 
-assert(sum(1, 2) == 3)
+assertEq(sum(1, 2), 3)
 breakpoint
 
-assert(sum(3, 3) == 6)
+assertEq(sum(3, 3), 6)
 breakpoint

wasm/wasm.go

@@ -96,7 +96,7 @@ func run(this js.Value, args []js.Value) interface{} {
 	vm := core.NewVM(compiler.Chunk, 256, 256)
 
 	// overwrite output
-	vm.SetGlobal("write", core.BuiltinFunctionValue{
+	vm.SetGlobal("write", &core.BuiltinFunctionValue{
 		Name:       "write",
 		Parameters: []string{"value"},
 		F: func(vm *core.VM, this core.Value, v map[string]core.Value) (core.Value, error) {
@@ -105,7 +105,7 @@ func run(this js.Value, args []js.Value) interface{} {
 			return nil, nil
 		},
 	})
-	vm.SetGlobal("print", core.BuiltinFunctionValue{
+	vm.SetGlobal("print", &core.BuiltinFunctionValue{
 		Name:       "print",
 		Parameters: []string{"value"},
 		F: func(vm *core.VM, this core.Value, v map[string]core.Value) (core.Value, error) {
@@ -115,7 +115,7 @@ func run(this js.Value, args []js.Value) interface{} {
 		},
 	})
 
-	for vm.HasNext() && vm.Next() {
+	for vm.Next() {
 	}
 
 	log.Println("Finished executing")