support toSet function

src/common/datatypes/Value.cpp

@@ -1893,6 +1893,27 @@ Value Value::toInt() const {
   }
 }
 
+Value Value::toSet() const {
+  switch (type_) {
+    case Value::Type::__EMPTY__:
+    case Value::Type::NULLVALUE: {
+      return Value::kNullValue;
+    }
+    case Value::Type::SET: {
+      return *this;
+    }
+    case Value::Type::LIST: {
+      Set set;
+      for (auto& item : getList().values) {
+        set.values.emplace(item);
+      }
+      return set;
+    }
+    default: {
+      return Value::kNullBadType;
+    }
+  }
+}
 Value Value::lessThan(const Value& v) const {
   if (empty() || v.empty()) {
     return (v.isNull() || isNull()) ? Value::kNullValue : Value::kEmpty;

src/common/datatypes/Value.h

@@ -347,6 +347,7 @@ struct Value {
   Value toBool() const;
   Value toFloat() const;
   Value toInt() const;
+  Value toSet() const;
 
   Value lessThan(const Value& v) const;
 

src/common/function/FunctionManager.cpp

@@ -182,6 +182,9 @@ std::unordered_map<std::string, std::vector<TypeSignature>> FunctionManager::typ
       TypeSignature({Value::Type::STRING}, Value::Type::NULLVALUE),
       TypeSignature({Value::Type::FLOAT}, Value::Type::INT),
       TypeSignature({Value::Type::INT}, Value::Type::INT)}},
+    {"toset",
+     {TypeSignature({Value::Type::LIST}, Value::Type::SET),
+      TypeSignature({Value::Type::SET}, Value::Type::SET)}},
     {"hash",
      {TypeSignature({Value::Type::INT}, Value::Type::INT),
       TypeSignature({Value::Type::FLOAT}, Value::Type::INT),
@@ -1429,6 +1432,13 @@ FunctionManager::FunctionManager() {
     attr.isPure_ = true;
     attr.body_ = [](const auto &args) -> Value { return Value(args[0].get()).toInt(); };
   }
+  {
+    auto &attr = functions_["toset"];
+    attr.minArity_ = 1;
+    attr.maxArity_ = 1;
+    attr.isPure_ = true;
+    attr.body_ = [](const auto &args) -> Value { return Value(args[0].get()).toSet(); };
+  }
   {
     auto &attr = functions_["lpad"];
     attr.minArity_ = 3;

tests/tck/features/expression/function/TypeConversion.feature

@@ -87,3 +87,34 @@ Feature: TypeConversion Expression
       YIELD [toInteger(true), toInteger(false)] AS yield_toInteger
       """
     Then a SemanticError should be raised at runtime: Type error `toInteger(true)'
+
+  Scenario: toSet
+    When executing query:
+      """
+      RETURN toSet(list[1,2,3,1,2]) AS list2set
+      """
+    Then the result should be, in any order:
+      | list2set  |
+      | {3, 1, 2} |
+    When executing query:
+      """
+      RETURN toSet(set{1,2,3,1,2}) AS set2set
+      """
+    Then the result should be, in any order:
+      | set2set   |
+      | {3, 1, 2} |
+    When executing query:
+      """
+      RETURN toSet(true) AS bool2set
+      """
+    Then a SemanticError should be raised at runtime: `toSet(true)' is not a valid expression : Parameter's type error
+    When executing query:
+      """
+      RETURN toSet(1) AS int2set
+      """
+    Then a SemanticError should be raised at runtime: `toSet(1)' is not a valid expression : Parameter's type error
+    When executing query:
+      """
+      RETURN toSet(3.4) AS float2set
+      """
+    Then a SemanticError should be raised at runtime: `toSet(3.4)' is not a valid expression : Parameter's type error