Added helper for operation enum conversion

Author: Innocent

src/iceberg/expression/json_internal.cc

@@ -32,14 +32,113 @@
 #include "iceberg/util/macros.h"
 
 namespace iceberg {
+namespace {
+// Expression type strings
+constexpr std::string_view kTypeTrue = "true";
+constexpr std::string_view kTypeFalse = "false";
+constexpr std::string_view kTypeEq = "eq";
+constexpr std::string_view kTypeAnd = "and";
+constexpr std::string_view kTypeOr = "or";
+constexpr std::string_view kTypeNot = "not";
+constexpr std::string_view kTypeIn = "in";
+constexpr std::string_view kTypeNotIn = "not-in";
+constexpr std::string_view kTypeLt = "lt";
+constexpr std::string_view kTypeLtEq = "lt-eq";
+constexpr std::string_view kTypeGt = "gt";
+constexpr std::string_view kTypeGtEq = "gt-eq";
+constexpr std::string_view kTypeNotEq = "not-eq";
+constexpr std::string_view kTypeStartsWith = "starts-with";
+constexpr std::string_view kTypeNotStartsWith = "not-starts-with";
+constexpr std::string_view kTypeIsNull = "is-null";
+constexpr std::string_view kTypeNotNull = "not-null";
+constexpr std::string_view kTypeIsNan = "is-nan";
+constexpr std::string_view kTypeNotNan = "not-nan";
+}  // namespace
+
+/// \brief Converts a JSON type string to an Expression::Operation.
+///
+/// \param type_str The JSON type string
+/// \return The corresponding Operation or an error if unknown
+Result<Expression::Operation> OperationTypeFromString(const std::string_view type_str) {
+  if (type_str == kTypeTrue) return Expression::Operation::kTrue;
+  if (type_str == kTypeFalse) return Expression::Operation::kFalse;
+  if (type_str == kTypeAnd) return Expression::Operation::kAnd;
+  if (type_str == kTypeOr) return Expression::Operation::kOr;
+  if (type_str == kTypeNot) return Expression::Operation::kNot;
+  if (type_str == kTypeEq) return Expression::Operation::kEq;
+  if (type_str == kTypeNotEq) return Expression::Operation::kNotEq;
+  if (type_str == kTypeLt) return Expression::Operation::kLt;
+  if (type_str == kTypeLtEq) return Expression::Operation::kLtEq;
+  if (type_str == kTypeGt) return Expression::Operation::kGt;
+  if (type_str == kTypeGtEq) return Expression::Operation::kGtEq;
+  if (type_str == kTypeIn) return Expression::Operation::kIn;
+  if (type_str == kTypeNotIn) return Expression::Operation::kNotIn;
+  if (type_str == kTypeIsNull) return Expression::Operation::kIsNull;
+  if (type_str == kTypeNotNull) return Expression::Operation::kNotNull;
+  if (type_str == kTypeIsNan) return Expression::Operation::kIsNan;
+  if (type_str == kTypeNotNan) return Expression::Operation::kNotNan;
+  if (type_str == kTypeStartsWith) return Expression::Operation::kStartsWith;
+  if (type_str == kTypeNotStartsWith) return Expression::Operation::kNotStartsWith;
+
+  return JsonParseError("Unknown expression type: {}", type_str);
+}
+
+/// \brief Converts an Expression::Operation to its JSON string representation.
+///
+/// \param op The operation to convert
+/// \return The JSON type string (e.g., "eq", "lt-eq", "is-null")
+std::string_view ToStringOperationType(Expression::Operation op) {
+  switch (op) {
+    case Expression::Operation::kTrue:
+      return kTypeTrue;
+    case Expression::Operation::kFalse:
+      return kTypeFalse;
+    case Expression::Operation::kAnd:
+      return kTypeAnd;
+    case Expression::Operation::kOr:
+      return kTypeOr;
+    case Expression::Operation::kNot:
+      return kTypeNot;
+    case Expression::Operation::kEq:
+      return kTypeEq;
+    case Expression::Operation::kNotEq:
+      return kTypeNotEq;
+    case Expression::Operation::kLt:
+      return kTypeLt;
+    case Expression::Operation::kLtEq:
+      return kTypeLtEq;
+    case Expression::Operation::kGt:
+      return kTypeGt;
+    case Expression::Operation::kGtEq:
+      return kTypeGtEq;
+    case Expression::Operation::kIn:
+      return kTypeIn;
+    case Expression::Operation::kNotIn:
+      return kTypeNotIn;
+    case Expression::Operation::kIsNull:
+      return kTypeIsNull;
+    case Expression::Operation::kNotNull:
+      return kTypeNotNull;
+    case Expression::Operation::kIsNan:
+      return kTypeIsNan;
+    case Expression::Operation::kNotNan:
+      return kTypeNotNan;
+    case Expression::Operation::kStartsWith:
+      return kTypeStartsWith;
+    case Expression::Operation::kNotStartsWith:
+      return kTypeNotStartsWith;
+    default:
+      return "unknown";
+  }
+}
 
 Result<std::shared_ptr<Expression>> ExpressionFromJson(const nlohmann::json& json) {
   // Handle boolean
   if (json.is_boolean()) {
     return json.get<bool>() ? std::static_pointer_cast<Expression>(True::Instance())
                             : std::static_pointer_cast<Expression>(False::Instance());
   }
-  return JsonParseError("Only boolean are currently supported");
+  return JsonParseError("Only booleans are currently supported");
 }
 
 nlohmann::json ToJson(const Expression& expr) {

src/iceberg/expression/json_internal.h

@@ -48,4 +48,17 @@ ICEBERG_DECLARE_JSON_SERDE(Expression)
 
 #undef ICEBERG_DECLARE_JSON_SERDE
 
+/// \brief Converts an operation type string to an Expression::Operation.
+///
+/// \param type_str The operation type string
+/// \return The corresponding Operation or an error if unknown
+ICEBERG_EXPORT Result<Expression::Operation> OperationTypeFromString(
+    const std::string_view type_str);
+
+/// \brief Converts an Expression::Operation to its string representation.
+///
+/// \param op The operation to convert
+/// \return The operation type string (e.g., "eq", "lt-eq", "is-null")
+ICEBERG_EXPORT std::string_view ToStringOperationType(Expression::Operation op);
+
 }  // namespace iceberg

src/iceberg/test/expression_json_test.cc

@@ -77,4 +77,9 @@ TEST_F(ExpressionJsonTest, FalseExpression) {
   EXPECT_EQ(result.value()->op(), Expression::Operation::kFalse);
 }
 
+TEST_F(ExpressionJsonTest, OpToString) {
+  EXPECT_EQ(OperationTypeFromString("true"), Expression::Operation::kTrue);
+  EXPECT_EQ("true", ToStringOperationType(Expression::Operation::kTrue));
+}
+
 }  // namespace iceberg