Feature: Implementation of array::join (#1920)

lib/fuzz/fuzz_targets/fuzz_executor.dict

@@ -160,6 +160,7 @@
 "array::group("
 "array::insert("
 "array::intersect("
+"array::join("
 "array::len("
 "array::max("
 "array::min("

lib/fuzz/fuzz_targets/fuzz_sql_parser.dict

@@ -160,6 +160,7 @@
 "array::group("
 "array::insert("
 "array::intersect("
+"array::join("
 "array::len("
 "array::max("
 "array::min("

lib/src/fnc/array.rs

@@ -97,6 +97,10 @@ pub fn intersect((array, other): (Array, Array)) -> Result<Value, Error> {
 	Ok(array.intersect(other).into())
 }
 
+pub fn join((arr, sep): (Array, String)) -> Result<Value, Error> {
+	Ok(arr.into_iter().map(|s| s.to_raw_string()).collect::<Vec<_>>().join(&sep).into())
+}
+
 pub fn len((array,): (Array,)) -> Result<Value, Error> {
 	Ok(array.len().into())
 }
@@ -217,7 +221,7 @@ pub mod sort {
 
 #[cfg(test)]
 mod tests {
-	use super::slice;
+	use super::{join, slice};
 	use crate::sql::{Array, Value};
 
 	#[test]
@@ -239,4 +243,26 @@ mod tests {
 		test(array, Some(-4), Some(2), &[b'd', b'e']);
 		test(array, Some(-4), Some(-1), &[b'd', b'e', b'f']);
 	}
+
+	#[test]
+	fn array_join() {
+		fn test(arr: Array, sep: &str, expected: &str) {
+			assert_eq!(join((arr, sep.to_string())).unwrap(), expected.into());
+		}
+
+		test(Vec::<Value>::new().into(), ",", "");
+		test(vec!["hello"].into(), ",", "hello");
+		test(vec!["hello", "world"].into(), ",", "hello,world");
+		test(vec!["again"; 512].into(), " and ", &vec!["again"; 512].join(" and "));
+		test(
+			vec![Value::from(true), Value::from(false), Value::from(true)].into(),
+			" is ",
+			"true is false is true",
+		);
+		test(
+			vec![Value::from(3.14), Value::from(2.72), Value::from(1.61)].into(),
+			" is not ",
+			"3.14 is not 2.72 is not 1.61",
+		);
+	}
 }

lib/src/fnc/mod.rs

@@ -77,6 +77,7 @@ pub fn synchronous(ctx: &Context<'_>, name: &str, args: Vec<Value>) -> Result<Va
 		"array::group" => array::group,
 		"array::insert" => array::insert,
 		"array::intersect" => array::intersect,
+		"array::join" => array::join,
 		"array::len" => array::len,
 		"array::max" => array::max,
 		"array::min" => array::min,

lib/src/sql/function.rs

@@ -309,6 +309,7 @@ fn function_array(i: &str) -> IResult<&str, &str> {
 		)),
 		alt((
 			tag("intersect"),
+			tag("join"),
 			tag("len"),
 			tag("max"),
 			tag("min"),

lib/tests/function.rs

@@ -403,6 +403,38 @@ async fn function_array_intersect() -> Result<(), Error> {
 	Ok(())
 }
 
+#[tokio::test]
+async fn function_string_join_arr() -> Result<(), Error> {
+	let sql = r#"
+		RETURN array::join([], "");
+		RETURN array::join(["hello", "world"], ", ");
+		RETURN array::join(["again", "again", "again"], " and ");
+		RETURN array::join([42, 3.14, 2.72, 1.61], " and ");
+	"#;
+	let dbs = Datastore::new("memory").await?;
+	let ses = Session::for_kv().with_ns("test").with_db("test");
+	let res = &mut dbs.execute(&sql, &ses, None, false).await?;
+	assert_eq!(res.len(), 4);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::from("");
+	assert_eq!(tmp, val);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::from("hello, world");
+	assert_eq!(tmp, val);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::from("again and again and again");
+	assert_eq!(tmp, val);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::from("42 and 3.14 and 2.72 and 1.61");
+	assert_eq!(tmp, val);
+	//
+	Ok(())
+}
+
 #[tokio::test]
 async fn function_array_len() -> Result<(), Error> {
 	let sql = r#"