don't export structs

Also remove StackTrace helper.
This would be better place in the errors package

error_code.go

@@ -165,11 +165,11 @@ type JSONFormat struct {
 	Others    []JSONFormat `json:"others,omitempty"`
 }
 
-// OperationClientData gives the results of both the ClientData and Operation functions.
+// operationClientData gives the results of both the ClientData and Operation functions.
 // The Operation function is applied to the original ErrorCode.
 // If that does not return an operation, it is applied to the result of ClientData.
 // This function is used by NewJSONFormat to fill JSONFormat.
-func OperationClientData(errCode ErrorCode) (string, interface{}) {
+func operationClientData(errCode ErrorCode) (string, interface{}) {
 	op := Operation(errCode)
 	data := ClientData(errCode)
 	if op == "" && data != nil {
@@ -196,7 +196,7 @@ func newJSONFormat(errCode ErrorCode, recur bool) JSONFormat {
 		}
 	}
 
-	op, data := OperationClientData(errCode)
+	op, data := operationClientData(errCode)
 
 	msg := GetUserMsg(errCode)
 	if msg == "" {

error_code_test.go

@@ -214,7 +214,7 @@ func TestNewInvalidInputErr(t *testing.T) {
 	ErrorEquals(t, err, "error")
 	ClientDataEquals(t, wrappedInternalErr, nil, internalCodeStr, MinimalError{})
 	// It should use the original stack trace, not the wrapped
-	AssertStackEquals(t, wrappedInternalErr, errcode.StackTrace(internalErr))
+	AssertStackEquals(t, wrappedInternalErr, StackTrace(internalErr))
 
 	err = errcode.NewInternalErr(InternalChild{})
 	AssertCode(t, err, internalChildCodeStr)
@@ -238,7 +238,7 @@ func TestStackTrace(t *testing.T) {
 	ErrorEquals(t, err, "errors stack")
 	ClientDataEquals(t, wrappedInternalErr, nil, internalCodeStr)
 	// It should use the original stack trace, not the wrapped
-	AssertStackEquals(t, wrappedInternalErr, errcode.StackTrace(err))
+	AssertStackEquals(t, wrappedInternalErr, StackTrace(err))
 }
 
 func TestNewInternalErr(t *testing.T) {
@@ -480,7 +480,7 @@ func jsonEquals(t *testing.T, errPrefix string, expectedIn interface{}, gotIn in
 
 func OpEquals(t *testing.T, code errcode.ErrorCode, op string) {
 	t.Helper()
-	opGot, _ := errcode.OperationClientData(code)
+	opGot := errcode.Operation(code)
 	if opGot != op {
 		t.Errorf("\nOp expected: %#v\n but got: %#v", op, opGot)
 	}
@@ -512,8 +512,20 @@ func AssertUserMsg(t *testing.T, v interface{}, msg string) {
 
 func AssertStackEquals(t *testing.T, given errcode.ErrorCode, stExpected stackfmt.StackTrace) {
 	t.Helper()
-	stGiven := errcode.StackTrace(given)
+	stGiven := StackTrace(given)
 	if stGiven == nil || stExpected == nil || stGiven[0] != stExpected[0] {
 		t.Errorf("\nStack expected: %#v\n Stack but got: %#v", stExpected[0], stGiven[0])
 	}
 }
+
+// StackTrace retrieves the errors.StackTrace from the error if it is present.
+// If there is not StackTrace it will return nil
+//
+// StackTrace looks to see if the error is a StackTracer or if an Unwrap of the error is a StackTracer.
+// It will return the stack trace from the deepest error it can find.
+func StackTrace(err error) stackfmt.StackTrace {
+	if tracer := errors.GetStackTracer(err); tracer != nil {
+		return tracer.StackTrace()
+	}
+	return nil
+}

operation.go

@@ -14,7 +14,7 @@ package errcode
 // GetOperation is defined, but generally the operation should be retrieved with Operation().
 // Operation() will check if a HasOperation interface exists.
 // As an alternative to defining this interface
-// you can use an existing wrapper (OpErrCode via AddOp) or embedding (EmbedOp) that has already defined it.
+// you can use an existing wrapper (AddOp) or embedding (EmbedOp) that has already defined it.
 type HasOperation interface {
 	GetOperation() string
 }
@@ -46,50 +46,50 @@ type OpCode interface {
 	HasOperation
 }
 
-// OpErrCode is an ErrorCode with an Operation field attached.
+// opErrCode is an ErrorCode with an Operation field attached.
 // This can be conveniently constructed with Op() and AddTo() to record the operation information for the error.
 // However, it isn't required to be used, see the HasOperation documentation for alternatives.
-type OpErrCode struct {
+type opErrCode struct {
 	ErrorCode
 	EmbedOp
 }
 
 // Unwrap satisfies the errors package Unwrap function
-func (e OpErrCode) Unwrap() error {
+func (e opErrCode) Unwrap() error {
 	return e.ErrorCode
 }
 
 // Error prefixes the operation to the underlying Err Error.
-func (e OpErrCode) Error() string {
+func (e opErrCode) Error() string {
 	return e.Op + ": " + e.ErrorCode.Error()
 }
 
-var _ ErrorCode = (*OpErrCode)(nil)    // assert implements interface
-var _ HasOperation = (*OpErrCode)(nil) // assert implements interface
-var _ OpCode = (*OpErrCode)(nil)       // assert implements interface
-var _ unwrapError = (*OpErrCode)(nil)  // assert implements interface
+var _ ErrorCode = (*opErrCode)(nil)    // assert implements interface
+var _ HasOperation = (*opErrCode)(nil) // assert implements interface
+var _ OpCode = (*opErrCode)(nil)       // assert implements interface
+var _ unwrapError = (*opErrCode)(nil)  // assert implements interface
 
 // AddOp is constructed by Op. It allows method chaining with AddTo.
-type AddOp func(ErrorCode) OpErrCode
+type AddOp func(ErrorCode) OpCode
 
 // AddTo adds the operation from Op to the ErrorCode
-func (addOp AddOp) AddTo(err ErrorCode) OpErrCode {
+func (addOp AddOp) AddTo(err ErrorCode) OpCode {
 	return addOp(err)
 }
 
 // Op adds an operation to an ErrorCode with AddTo.
-// This converts the error to the type OpErrCode.
+// This converts the error to the type OpCode.
 //
 //	op := errcode.Op("path.move.x")
 //	if start < obstable && obstacle < end  {
 //		return op.AddTo(PathBlocked{start, end, obstacle})
 //	}
 func Op(operation string) AddOp {
-	return func(err ErrorCode) OpErrCode {
+	return func(err ErrorCode) OpCode {
 		if err == nil {
 			panic("Op errorcode is nil")
 		}
-		return OpErrCode{
+		return opErrCode{
 			ErrorCode: err,
 			EmbedOp:   EmbedOp{Op: operation},
 		}

stack.go

@@ -9,18 +9,6 @@ import (
 	"github.com/gregwebs/stackfmt"
 )
 
-// StackTrace retrieves the errors.StackTrace from the error if it is present.
-// If there is not StackTrace it will return nil
-//
-// StackTrace looks to see if the error is a StackTracer or if an Unwrap of the error is a StackTracer.
-// It will return the stack trace from the deepest error it can find.
-func StackTrace(err error) stackfmt.StackTrace {
-	if tracer := errors.GetStackTracer(err); tracer != nil {
-		return tracer.StackTrace()
-	}
-	return nil
-}
-
 // StackCode is an [ErrorCode] with stack trace information attached.
 // This may be used as a convenience to record the strack trace information for the error.
 // Stack traces are provided by [NewInternalErr].

user.go

@@ -46,32 +46,32 @@ func (e EmbedUserMsg) GetUserMsg() string {
 	return e.Msg
 }
 
-// UserMsgErrCode is an ErrorCode with a Msg field attached.
+// userMsgErrCode is an ErrorCode with a Msg field attached.
 // This can be conveniently constructed with NewUserMsg and AddTo or WithUserMsg
 // see the HasUserMsg documentation for alternatives.
-type UserMsgErrCode struct {
+type userMsgErrCode struct {
 	ErrorCode
 	Msg string
 }
 
 // Unwrap satisfies the errors package Unwrap function
-func (e UserMsgErrCode) Unwrap() error {
+func (e userMsgErrCode) Unwrap() error {
 	return e.ErrorCode
 }
 
 // Error prefixes the user message to the underlying Err Error.
-func (e UserMsgErrCode) Error() string {
+func (e userMsgErrCode) Error() string {
 	return e.Msg + ": " + e.ErrorCode.Error()
 }
 
 // GetUserMsg satisfies the [HasUserMsg] interface.
-func (e UserMsgErrCode) GetUserMsg() string {
+func (e userMsgErrCode) GetUserMsg() string {
 	return e.Msg
 }
 
-var _ ErrorCode = (*UserMsgErrCode)(nil)   // assert implements interface
-var _ HasUserMsg = (*UserMsgErrCode)(nil)  // assert implements interface
-var _ unwrapError = (*UserMsgErrCode)(nil) // assert implements interface
+var _ ErrorCode = (*userMsgErrCode)(nil)   // assert implements interface
+var _ HasUserMsg = (*userMsgErrCode)(nil)  // assert implements interface
+var _ unwrapError = (*userMsgErrCode)(nil) // assert implements interface
 
 // AddUserMsg is constructed by UserMsg. It allows method chaining with AddTo.
 type AddUserMsg func(ErrorCode) UserCode
@@ -94,11 +94,11 @@ func UserMsg(msg string) AddUserMsg {
 	}
 }
 
-// WithUserMsg creates a UserMsgErrCode
+// WithUserMsg creates a UserCode
 // Panics if msg is empty or err is nil.
 func WithUserMsg(msg string, err ErrorCode) UserCode {
 	if err == nil {
 		return nil
 	}
-	return UserMsgErrCode{Msg: msg, ErrorCode: err}
+	return userMsgErrCode{Msg: msg, ErrorCode: err}
 }