fix(rpn): DIP violation — NewOperatorRegistry accepts OperatorProvider interface (nj)

Accept the OperatorProvider interface instead of concrete *Operations in
NewOperatorRegistry() and all register* methods.  OperatorProvider embeds
ArithmeticOperator, PowerIntOperator, LogarithmicOperator, BooleanOperator,
StackOperator, VariableOperator, ConstantOperator, MetricOperator, and
HyperOperator, allowing mocking or alternative implementations.

3 files changed, 22 insertions, 7 deletions

diff --git a/internal/rpn/operations.go b/internal/rpn/operations.go
index e5cc891..832ac77 100644
--- a/internal/rpn/operations.go
+++ b/internal/rpn/operations.go
@@ -32,6 +32,7 @@ var (
 	_ MetricCommander       = (*Operations)(nil)
 	_ CustomMetricManager   = (*Operations)(nil)
 	_ OperationsProvider    = (*Operations)(nil)
+	_ OperatorProvider      = (*Operations)(nil)
 )
 
 // NewOperations creates a new Operations instance with the given variable store.
diff --git a/internal/rpn/operations_interfaces.go b/internal/rpn/operations_interfaces.go
index 7542993..cc60db2 100644
--- a/internal/rpn/operations_interfaces.go
+++ b/internal/rpn/operations_interfaces.go
@@ -101,6 +101,20 @@ type CustomMetricManager interface {
 	CustomUndefine(name string) error
 }
 
+// OperatorProvider combines all operator interfaces needed by the OperatorRegistry.
+// This satisfies DIP by decoupling the registry from the concrete *Operations type.
+type OperatorProvider interface {
+	ArithmeticOperator
+	PowerIntOperator
+	LogarithmicOperator
+	BooleanOperator
+	StackOperator
+	VariableOperator
+	ConstantOperator
+	MetricOperator
+	HyperOperator
+}
+
 // OperationsProvider combines all interfaces that RPN needs from Operations.
 // RPN depends on this interface (DIP) rather than the concrete *Operations type.
 type OperationsProvider interface {
diff --git a/internal/rpn/operator_registry.go b/internal/rpn/operator_registry.go
index 67898e5..605d1d7 100644
--- a/internal/rpn/operator_registry.go
+++ b/internal/rpn/operator_registry.go
@@ -17,7 +17,7 @@ type OperatorRegistry struct {
 }
 
 // NewOperatorRegistry creates a new operator registry and registers all operators.
-func NewOperatorRegistry(op *Operations) *OperatorRegistry {
+func NewOperatorRegistry(op OperatorProvider) *OperatorRegistry {
 	registry := &OperatorRegistry{
 		standardOperators: make(map[string]OperatorHandler),
 		hyperOperators:    make(map[string]OperatorHandler),
@@ -34,7 +34,7 @@ func NewOperatorRegistry(op *Operations) *OperatorRegistry {
 }
 
 // registerArithmeticOperators registers math and numeric operators.
-func (r *OperatorRegistry) registerArithmeticOperators(op *Operations) {
+func (r *OperatorRegistry) registerArithmeticOperators(op OperatorProvider) {
 	r.registerStandardOperator("+", func(stack *Stack) error { return op.Add(stack) })
 	r.registerStandardOperator("-", func(stack *Stack) error { return op.Subtract(stack) })
 	r.registerStandardOperator("*", func(stack *Stack) error { return op.Multiply(stack) })
@@ -48,7 +48,7 @@ func (r *OperatorRegistry) registerArithmeticOperators(op *Operations) {
 }
 
 // registerComparisonOperators registers equality and ordering operators.
-func (r *OperatorRegistry) registerComparisonOperators(op *Operations) {
+func (r *OperatorRegistry) registerComparisonOperators(op OperatorProvider) {
 	r.registerStandardOperator("gt", func(stack *Stack) error { return op.GT(stack) })
 	r.registerStandardOperator("lt", func(stack *Stack) error { return op.LT(stack) })
 	r.registerStandardOperator("<", func(stack *Stack) error { return op.LT(stack) })
@@ -64,7 +64,7 @@ func (r *OperatorRegistry) registerComparisonOperators(op *Operations) {
 }
 
 // registerStackOperators registers stack manipulation operators.
-func (r *OperatorRegistry) registerStackOperators(op *Operations) {
+func (r *OperatorRegistry) registerStackOperators(op OperatorProvider) {
 	r.registerStandardOperator("dup", func(stack *Stack) error { return op.Dup(stack) })
 	r.registerStandardOperator("swap", func(stack *Stack) error { return op.Swap(stack) })
 	r.registerStandardOperator("pop", func(stack *Stack) error { return op.Pop(stack) })
@@ -87,14 +87,14 @@ func (r *OperatorRegistry) registerStackOperators(op *Operations) {
 }
 
 // registerVariableOperators registers assignment and conversion operators.
-func (r *OperatorRegistry) registerVariableOperators(op *Operations) {
+func (r *OperatorRegistry) registerVariableOperators(op OperatorProvider) {
 	r.registerStandardOperator(":=", func(stack *Stack) error { return op.AssignRight(stack) })
 	r.registerStandardOperator("=:", func(stack *Stack) error { return op.AssignLeft(stack) })
 	r.registerStandardOperator("convert", func(stack *Stack) error { return op.Convert(stack) })
 }
 
 // registerCommandOperators registers operators that return a result immediately.
-func (r *OperatorRegistry) registerCommandOperators(op *Operations) {
+func (r *OperatorRegistry) registerCommandOperators(op OperatorProvider) {
 	r.registerCommandOperator("show", func(stack *Stack) (string, error) { return op.Show(stack) })
 	r.registerCommandOperator("showstack", func(stack *Stack) (string, error) { return op.Show(stack) })
 	r.registerCommandOperator("print", func(stack *Stack) (string, error) { return op.Show(stack) })
@@ -105,7 +105,7 @@ func (r *OperatorRegistry) registerCommandOperators(op *Operations) {
 }
 
 // registerHyperOperators registers hyper (vectorized) operators.
-func (r *OperatorRegistry) registerHyperOperators(op *Operations) {
+func (r *OperatorRegistry) registerHyperOperators(op OperatorProvider) {
 	r.registerHyperOperator("[+]", func(stack *Stack) error { return op.HyperAdd(stack) })
 	r.registerHyperOperator("[-]", func(stack *Stack) error { return op.HyperSubtract(stack) })
 	r.registerHyperOperator("[*]", func(stack *Stack) error { return op.HyperMultiply(stack) })