Hint reference parsing (#625)

* add current failing tests

* add new grammar

* fix parsing of number as string

* fix grammar to operate sub correctly

* add explanation comments

---------

Co-authored-by: Shourya Goel <shouryagoel10000@gmail.com>

pkg/hintrunner/hinter/operand.go

@@ -147,26 +147,23 @@ type Operator uint8
 const (
 	Add Operator = iota
 	Mul
+	Sub
 )
 
 type BinaryOp struct {
 	Operator Operator
-	Lhs      CellRefer
-	Rhs      ResOperander // (except DoubleDeref and BinaryOp)
+	Lhs      ResOperander
+	Rhs      ResOperander
 }
 
 func (bop BinaryOp) String() string {
 	return "BinaryOperator"
 }
 
 func (bop BinaryOp) Resolve(vm *VM.VirtualMachine) (mem.MemoryValue, error) {
-	lhsAddr, err := bop.Lhs.Get(vm)
+	lhs, err := bop.Lhs.Resolve(vm)
 	if err != nil {
-		return mem.UnknownValue, fmt.Errorf("get lhs address %s: %w", bop.Lhs, err)
-	}
-	lhs, err := vm.Memory.ReadFromAddress(&lhsAddr)
-	if err != nil {
-		return mem.UnknownValue, fmt.Errorf("read lhs address %s: %w", lhsAddr, err)
+		return mem.UnknownValue, fmt.Errorf("resolve lhs operand %s: %w", lhs, err)
 	}
 
 	rhs, err := bop.Rhs.Resolve(vm)
@@ -221,7 +218,7 @@ func (v DoubleDeref) ApplyApTracking(hint, ref zero.ApTracking) Reference {
 }
 
 func (v BinaryOp) ApplyApTracking(hint, ref zero.ApTracking) Reference {
-	v.Lhs = v.Lhs.ApplyApTracking(hint, ref).(CellRefer)
+	v.Lhs = v.Lhs.ApplyApTracking(hint, ref).(ResOperander)
 	v.Rhs = v.Rhs.ApplyApTracking(hint, ref).(ResOperander)
 	return v
 }

pkg/hintrunner/hinter/operand_test.go

@@ -127,19 +127,20 @@ func TestResolveAddOp(t *testing.T) {
 		memory.MemoryValueFromInt(30),
 	)
 
-	// lhs
+	// Lhs
 	var ap ApCellRef = 7
+	lhs := Deref{ap}
 
 	// Rhs
 	var fp FpCellRef = 20
-	deref := Deref{fp}
+	rhs := Deref{fp}
 
 	operator := Add
 
 	bop := BinaryOp{
 		Operator: operator,
-		Lhs:      ap,
-		Rhs:      deref,
+		Lhs:      lhs,
+		Rhs:      rhs,
 	}
 
 	res, err := bop.Resolve(vm)
@@ -164,19 +165,20 @@ func TestResolveMulOp(t *testing.T) {
 		memory.MemoryValueFromInt(5),
 	)
 
-	// lhs
+	// Lhs
 	var ap ApCellRef = 7
+	lhs := Deref{ap}
 
 	// Rhs
 	var fp FpCellRef = 20
-	deref := Deref{fp}
+	rhs := Deref{fp}
 
 	operator := Mul
 
 	bop := BinaryOp{
 		Operator: operator,
-		Lhs:      ap,
-		Rhs:      deref,
+		Lhs:      lhs,
+		Rhs:      rhs,
 	}
 
 	res, err := bop.Resolve(vm)