Add SQL array::complement function

Closes #1315

lib/src/fnc/array.rs

@@ -1,5 +1,6 @@
 use crate::err::Error;
 use crate::sql::array::Combine;
+use crate::sql::array::Complement;
 use crate::sql::array::Concat;
 use crate::sql::array::Difference;
 use crate::sql::array::Intersect;
@@ -7,16 +8,23 @@ use crate::sql::array::Union;
 use crate::sql::array::Uniq;
 use crate::sql::value::Value;
 
-pub fn concat(arrays: (Value, Value)) -> Result<Value, Error> {
+pub fn combine(arrays: (Value, Value)) -> Result<Value, Error> {
 	Ok(match arrays {
-		(Value::Array(v), Value::Array(w)) => v.concat(w).into(),
+		(Value::Array(v), Value::Array(w)) => v.combine(w).into(),
 		_ => Value::None,
 	})
 }
 
-pub fn combine(arrays: (Value, Value)) -> Result<Value, Error> {
+pub fn complement(arrays: (Value, Value)) -> Result<Value, Error> {
 	Ok(match arrays {
-		(Value::Array(v), Value::Array(w)) => v.combine(w).into(),
+		(Value::Array(v), Value::Array(w)) => v.complement(w).into(),
+		_ => Value::None,
+	})
+}
+
+pub fn concat(arrays: (Value, Value)) -> Result<Value, Error> {
+	Ok(match arrays {
+		(Value::Array(v), Value::Array(w)) => v.concat(w).into(),
 		_ => Value::None,
 	})
 }

lib/src/fnc/mod.rs

@@ -60,6 +60,7 @@ pub fn synchronous(ctx: &Context<'_>, name: &str, args: Vec<Value>) -> Result<Va
 		name,
 		args,
 		"array::combine" => array::combine,
+		"array::complement" => array::complement,
 		"array::concat" => array::concat,
 		"array::difference" => array::difference,
 		"array::distinct" => array::distinct,

lib/src/sql/array.rs

@@ -251,6 +251,24 @@ impl Combine<Array> for Array {
 
 // ------------------------------
 
+pub trait Complement<T> {
+	fn complement(self, other: T) -> T;
+}
+
+impl Complement<Array> for Array {
+	fn complement(self, other: Self) -> Array {
+		let mut out = Array::new();
+		for v in self.into_iter() {
+			if other.contains(&v) {
+				out.push(v)
+			}
+		}
+		out
+	}
+}
+
+// ------------------------------
+
 pub trait Concat<T> {
 	fn concat(self, other: T) -> T;
 }
@@ -269,14 +287,13 @@ pub trait Difference<T> {
 }
 
 impl Difference<Array> for Array {
-	fn difference(self, other: Array) -> Array {
+	fn difference(self, mut other: Array) -> Array {
 		let mut out = Array::new();
-		let mut other: Vec<_> = other.into_iter().collect();
-		for a in self.into_iter() {
-			if let Some(pos) = other.iter().position(|b| a == *b) {
+		for v in self.into_iter() {
+			if let Some(pos) = other.iter().position(|w| v == *w) {
 				other.remove(pos);
 			} else {
-				out.push(a);
+				out.push(v);
 			}
 		}
 		out.append(&mut other);
@@ -291,13 +308,12 @@ pub trait Intersect<T> {
 }
 
 impl Intersect<Self> for Array {
-	fn intersect(self, other: Self) -> Self {
+	fn intersect(self, mut other: Self) -> Self {
 		let mut out = Self::new();
-		let mut other: Vec<_> = other.into_iter().collect();
-		for a in self.0.into_iter() {
-			if let Some(pos) = other.iter().position(|b| a == *b) {
-				out.push(a);
+		for v in self.0.into_iter() {
+			if let Some(pos) = other.iter().position(|w| v == *w) {
 				other.remove(pos);
+				out.push(v);
 			}
 		}
 		out

lib/src/sql/function.rs

@@ -231,6 +231,7 @@ fn function_names(i: &str) -> IResult<&str, &str> {
 fn function_array(i: &str) -> IResult<&str, &str> {
 	alt((
 		tag("array::combine"),
+		tag("array::complement"),
 		tag("array::concat"),
 		tag("array::difference"),
 		tag("array::distinct"),

lib/src/sql/operator.rs

@@ -48,8 +48,9 @@ pub enum Operator {
 	AllInside,   // ⊆
 	AnyInside,   // ⊂
 	NoneInside,  // ⊄
-	Outside,     // ∈
-	Intersects,  // ∩
+	//
+	Outside,
+	Intersects,
 }
 
 impl Default for Operator {