Empty array

pkg/compiler/allocator.go

@@ -31,7 +31,7 @@ type (
 func NewRegisterAllocator() *RegisterAllocator {
 	return &RegisterAllocator{
 		registers:    make(map[runtime.Operand]*RegisterStatus),
-		nextRegister: 0,
+		nextRegister: runtime.ResultOperand + 1, // we start at 1 to avoid ResultOperand
 		lifetimes:    make(map[string]*RegisterLifetime),
 		usageGraph:   make(map[runtime.Operand]map[runtime.Operand]bool),
 	}

pkg/compiler/compiler_test.go

@@ -19,31 +19,31 @@ func TestVariables(t *testing.T) {
 			nil,
 			nil,
 		},
-		//{
-		//	`LET a = TRUE RETURN a`,
-		//	true,
-		//	nil,
-		//},
-		//{
-		//	`LET a = 1 RETURN a`,
-		//	1,
-		//	nil,
-		//},
-		//{
-		//	`LET a = 1.1 RETURN a`,
-		//	1.1,
-		//	nil,
-		//},
-		//{
-		//	`LET i = 'foo' RETURN i`,
-		//	"foo",
-		//	nil,
-		//},
-		//{
-		//	`LET i = [] RETURN i`,
-		//	[]any{},
-		//	ShouldEqualJSON,
-		//},
+		{
+			`LET a = TRUE RETURN a`,
+			true,
+			nil,
+		},
+		{
+			`LET a = 1 RETURN a`,
+			1,
+			nil,
+		},
+		{
+			`LET a = 1.1 RETURN a`,
+			1.1,
+			nil,
+		},
+		{
+			`LET i = 'foo' RETURN i`,
+			"foo",
+			nil,
+		},
+		{
+			`LET i = [] RETURN i`,
+			[]any{},
+			ShouldEqualJSON,
+		},
 		//{
 		//	`LET i = [1, 2, 3] RETURN i`,
 		//	[]any{1, 2, 3},

pkg/compiler/emitter.go

@@ -31,6 +31,11 @@ func (e *Emitter) EmitAB(op runtime.Opcode, dest, src1 runtime.Operand) {
 	e.EmitABC(op, dest, src1, 0)
 }
 
+// EmitABx emits an opcode with a destination register and a custom argument.
+func (e *Emitter) EmitABx(op runtime.Opcode, dest runtime.Operand, arg int) {
+	e.EmitABC(op, dest, runtime.Operand(arg), 0)
+}
+
 // EmitABC emits an opcode with a destination register and two source register arguments.
 func (e *Emitter) EmitABC(op runtime.Opcode, dest, src1, src2 runtime.Operand) {
 	e.instructions = append(e.instructions, runtime.Instruction{

pkg/compiler/symbols.go

@@ -9,7 +9,7 @@ import (
 type SymbolTable struct {
 	constants      []core.Value
 	constantsIndex map[uint64]int
-	globals        map[string]int
+	globals        map[string]runtime.Operand
 	scope          int
 	locals         []Variable
 	registers      *RegisterAllocator
@@ -19,7 +19,7 @@ func NewSymbolTable(registers *RegisterAllocator) *SymbolTable {
 	return &SymbolTable{
 		constants:      make([]core.Value, 0),
 		constantsIndex: make(map[uint64]int),
-		globals:        make(map[string]int),
+		globals:        make(map[string]runtime.Operand),
 		locals:         make([]Variable, 0),
 		registers:      registers,
 	}
@@ -62,8 +62,6 @@ func (st *SymbolTable) AddConstant(constant core.Value) runtime.Operand {
 }
 
 func (st *SymbolTable) DefineVariable(name string) runtime.Operand {
-	var index int
-
 	if st.scope == 0 {
 		// Check for duplicate global variable names.
 		_, ok := st.globals[name]
@@ -72,12 +70,11 @@ func (st *SymbolTable) DefineVariable(name string) runtime.Operand {
 			panic(core.Error(ErrVariableNotUnique, name))
 		}
 
-		index = len(st.globals)
+		op := st.AddConstant(values.NewString(name))
 		// Define global variable.
-		st.globals[name] = index
+		st.globals[name] = op
 
-		// Return a constant operand to indicate that this is a global variable and use its index.
-		return st.AddConstant(values.NewString(name))
+		return op
 	}
 
 	register := st.registers.AllocateLocalVar(name)
@@ -88,7 +85,7 @@ func (st *SymbolTable) DefineVariable(name string) runtime.Operand {
 		Register: register,
 	})
 
-	return runtime.NewRegisterOperand(index)
+	return register
 }
 
 func (st *SymbolTable) LookupVariable(name string) runtime.Operand {
@@ -99,13 +96,13 @@ func (st *SymbolTable) LookupVariable(name string) runtime.Operand {
 		}
 	}
 
-	index, ok := st.globals[name]
+	op, ok := st.globals[name]
 
 	if !ok {
 		panic(core.Error(ErrVariableNotFound, name))
 	}
 
-	return runtime.NewConstantOperand(index)
+	return op
 }
 
 func (st *SymbolTable) ExitScope() {

pkg/compiler/visitor.go

@@ -491,16 +491,21 @@ func (v *visitor) VisitVariable(ctx *fql.VariableContext) interface{} {
 }
 
 func (v *visitor) VisitArrayLiteral(ctx *fql.ArrayLiteralContext) interface{} {
-	//var size int
-	//
-	//if args := ctx.ArgumentList(); args != nil {
-	//	out := v.VisitArgumentList(args.(*fql.ArgumentListContext))
-	//	size = out.(int)
-	//}
-	//
-	//v.emitter.EmitABC(runtime.OpArray, size)
+	dest := v.registers.Allocate(VarTemporary)
+	var size int
 
-	return nil
+	if args := ctx.ArgumentList(); args != nil {
+		exps := args.AllExpression()
+		size = len(exps)
+
+		//for _, arg := range exps {
+		//	arg.Accept(v)
+		//}
+	}
+
+	v.emitter.EmitABx(runtime.OpArray, dest, size)
+
+	return dest
 }
 
 func (v *visitor) VisitArgumentList(ctx *fql.ArgumentListContext) interface{} {
@@ -664,7 +669,12 @@ func (v *visitor) VisitLiteral(ctx *fql.LiteralContext) interface{} {
 func (v *visitor) VisitReturnExpression(ctx *fql.ReturnExpressionContext) interface{} {
 	valReg := ctx.Expression().Accept(v).(runtime.Operand)
 
-	v.emitter.EmitAB(runtime.OpMove, runtime.ResultOperand, valReg)
+	if valReg.IsConstant() {
+		v.emitter.EmitAB(runtime.OpLoadGlobal, runtime.ResultOperand, valReg)
+	} else {
+		v.emitter.EmitAB(runtime.OpMove, runtime.ResultOperand, valReg)
+	}
+
 	v.emitter.Emit(runtime.OpReturn)
 
 	//if len(v.loops) == 0 {

pkg/runtime/opcode.go

@@ -17,6 +17,8 @@ const (
 	OpDecr
 
 	OpArray
+	OpStoreIndex
+
 	OpObject
 	OpLoadProperty
 	OpLoadPropertyOptional

pkg/runtime/vm.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"github.com/MontFerret/ferret/pkg/runtime/core"
 	"github.com/MontFerret/ferret/pkg/runtime/operators"
+	"github.com/MontFerret/ferret/pkg/runtime/values"
 )
 
 type VM struct {
@@ -55,7 +56,7 @@ loop:
 		case OpStoreGlobal:
 			vm.globals[program.Constants[dst.Constant()].String()] = vm.load(src1)
 		case OpLoadGlobal:
-			reg[dst] = vm.globals[program.Constants[src1].String()]
+			reg[dst] = vm.globals[program.Constants[src1.Constant()].String()]
 		case OpAdd:
 			reg[dst] = operators.Add(vm.load(src1), vm.load(src2))
 		case OpSub:
@@ -75,8 +76,7 @@ loop:
 			//stack.Push(values.ToBoolean(stack.Pop()))
 
 		case OpArray:
-			//size := arg
-			//arr := values.NewSizedArray(size)
+			arr := values.NewSizedArray(int(src1))
 			//
 			//// iterate from the end to the beginning
 			//// because stack is LIFO
@@ -85,6 +85,7 @@ loop:
 			//}
 			//
 			//stack.Push(arr)
+			reg[dst] = arr
 
 		case OpObject:
 			//obj := values.NewObject()