From 054c127175bdceb7322165c2bf0374741574cd34 Mon Sep 17 00:00:00 2001
From: Marin Tomic <marin.tomic@memgraph.io>
Date: Fri, 15 Jun 2018 10:40:51 +0200
Subject: [PATCH] Implement toString function
Summary: https://neo4j.com/docs/developer-manual/3.4/cypher/functions/string/#functions-tostring
Reviewers: teon.banek, buda
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1430
---
.../interpret/awesome_memgraph_functions.cpp | 24 ++++++++++
tests/unit/query_expression_evaluator.cpp | 44 +++++++++++++++++++
2 files changed, 68 insertions(+)
diff --git a/src/query/interpret/awesome_memgraph_functions.cpp b/src/query/interpret/awesome_memgraph_functions.cpp
index 53cf70c15..a9fb16341 100644
--- a/src/query/interpret/awesome_memgraph_functions.cpp
+++ b/src/query/interpret/awesome_memgraph_functions.cpp
@@ -655,6 +655,29 @@ TypedValue Id(const std::vector<TypedValue> &args,
}
}
+TypedValue ToString(const std::vector<TypedValue> &args,
+ database::GraphDbAccessor &) {
+ if (args.size() != 1U) {
+ throw QueryRuntimeException("toString takes one argument");
+ }
+ auto &arg = args[0];
+ switch (arg.type()) {
+ case TypedValue::Type::Null:
+ return TypedValue::Null;
+ case TypedValue::Type::String:
+ return arg;
+ case TypedValue::Type::Int:
+ return std::to_string(arg.ValueInt());
+ case TypedValue::Type::Double:
+ return std::to_string(arg.ValueDouble());
+ case TypedValue::Type::Bool:
+ return arg.ValueBool() ? "true" : "false";
+ default:
+ throw QueryRuntimeException(
+ "toString argument must be a number, string or boolean");
+ }
+}
+
} // namespace
std::function<TypedValue(const std::vector<TypedValue> &,
@@ -706,6 +729,7 @@ NameToFunction(const std::string &function_name) {
if (function_name == "INDEXINFO") return IndexInfo;
if (function_name == "WORKERID") return WorkerId;
if (function_name == "ID") return Id;
+ if (function_name == "TOSTRING") return ToString;
return nullptr;
}
} // namespace query
diff --git a/tests/unit/query_expression_evaluator.cpp b/tests/unit/query_expression_evaluator.cpp
index 0cd4b59bb..c319f6e2e 100644
--- a/tests/unit/query_expression_evaluator.cpp
+++ b/tests/unit/query_expression_evaluator.cpp
@@ -1424,4 +1424,48 @@ TEST(ExpressionEvaluator, FunctionWorkerIdSingleNode) {
EXPECT_EQ(EvaluateFunction("WORKERID", {va}, db).Value<int64_t>(),
db.WorkerId());
}
+
+TEST(ExpressionEvaluator, FunctionToStringNull) {
+ database::SingleNode db;
+ EXPECT_TRUE(EvaluateFunction("TOSTRING", {TypedValue::Null}, db).IsNull());
+}
+
+TEST(ExpressionEvaluator, FunctionToStringString) {
+ database::SingleNode db;
+ EXPECT_EQ(EvaluateFunction("TOSTRING", {""}, db).ValueString(), "");
+ EXPECT_EQ(
+ EvaluateFunction("TOSTRING", {"this is a string"}, db).ValueString(),
+ "this is a string");
+}
+
+TEST(ExpressionEvaluator, FunctionToStringInteger) {
+ database::SingleNode db;
+ EXPECT_EQ(EvaluateFunction("TOSTRING", {-23321312}, db).ValueString(),
+ "-23321312");
+ EXPECT_EQ(EvaluateFunction("TOSTRING", {0}, db).ValueString(), "0");
+ EXPECT_EQ(EvaluateFunction("TOSTRING", {42}, db).ValueString(), "42");
+}
+
+TEST(ExpressionEvaluator, FunctionToStringDouble) {
+ database::SingleNode db;
+ EXPECT_EQ(EvaluateFunction("TOSTRING", {-42.42}, db).ValueString(),
+ "-42.420000");
+ EXPECT_EQ(EvaluateFunction("TOSTRING", {0.0}, db).ValueString(), "0.000000");
+ EXPECT_EQ(EvaluateFunction("TOSTRING", {238910.2313217}, db).ValueString(),
+ "238910.231322");
+}
+
+TEST(ExpressionEvaluator, FunctionToStringBool) {
+ database::SingleNode db;
+ EXPECT_EQ(EvaluateFunction("TOSTRING", {true}, db).ValueString(), "true");
+ EXPECT_EQ(EvaluateFunction("TOSTRING", {false}, db).ValueString(), "false");
+}
+
+TEST(ExpressionEvaluator, FunctionToStringExceptions) {
+ database::SingleNode db;
+ EXPECT_THROW(EvaluateFunction("TOSTRING", {1, 2, 3}, db),
+ QueryRuntimeException);
+ std::vector<TypedValue> l{1, 2, 3};
+ EXPECT_THROW(EvaluateFunction("TOSTRING", l, db), QueryRuntimeException);
+}
} // namespace