Feature - unary operators (#2139)

lib/src/doc/table.rs

@@ -321,7 +321,7 @@ impl<'a> Document<'a> {
 				Operator::Equal,
 				Value::Subquery(Box::new(Subquery::Ifelse(IfelseStatement {
 					exprs: vec![(
-						Value::Expression(Box::new(Expression {
+						Value::Expression(Box::new(Expression::Binary {
 							l: Value::Idiom(key.clone()),
 							o: Operator::MoreThan,
 							r: val.clone(),
@@ -341,7 +341,7 @@ impl<'a> Document<'a> {
 				Operator::Equal,
 				Value::Subquery(Box::new(Subquery::Ifelse(IfelseStatement {
 					exprs: vec![(
-						Value::Expression(Box::new(Expression {
+						Value::Expression(Box::new(Expression::Binary {
 							l: Value::Idiom(key.clone()),
 							o: Operator::LessThan,
 							r: val.clone(),
@@ -363,13 +363,13 @@ impl<'a> Document<'a> {
 		ops.push((
 			key.clone(),
 			Operator::Equal,
-			Value::Expression(Box::new(Expression {
+			Value::Expression(Box::new(Expression::Binary {
 				l: Value::Subquery(Box::new(Subquery::Value(Value::Expression(Box::new(
-					Expression {
+					Expression::Binary {
 						l: Value::Subquery(Box::new(Subquery::Value(Value::Expression(Box::new(
-							Expression {
+							Expression::Binary {
 								l: Value::Subquery(Box::new(Subquery::Value(Value::Expression(
-									Box::new(Expression {
+									Box::new(Expression::Binary {
 										l: Value::Idiom(key),
 										o: Operator::Nco,
 										r: Value::Number(Number::Int(0)),
@@ -377,7 +377,7 @@ impl<'a> Document<'a> {
 								)))),
 								o: Operator::Mul,
 								r: Value::Subquery(Box::new(Subquery::Value(Value::Expression(
-									Box::new(Expression {
+									Box::new(Expression::Binary {
 										l: Value::Idiom(key_c.clone()),
 										o: Operator::Nco,
 										r: Value::Number(Number::Int(0)),
@@ -395,9 +395,9 @@ impl<'a> Document<'a> {
 				))))),
 				o: Operator::Div,
 				r: Value::Subquery(Box::new(Subquery::Value(Value::Expression(Box::new(
-					Expression {
+					Expression::Binary {
 						l: Value::Subquery(Box::new(Subquery::Value(Value::Expression(Box::new(
-							Expression {
+							Expression::Binary {
 								l: Value::Idiom(key_c.clone()),
 								o: Operator::Nco,
 								r: Value::Number(Number::Int(0)),

lib/src/err/mod.rs

@@ -430,6 +430,10 @@ pub enum Error {
 	#[error("Cannot raise the value '{0}' with '{1}'")]
 	TryPow(String, String),
 
+	/// Cannot perform negation
+	#[error("Cannot negate the value '{0}'")]
+	TryNeg(String),
+
 	/// It's is not possible to convert between the two types
 	#[error("Cannot convert from '{0}' to '{1}'")]
 	TryFrom(String, &'static str),

lib/src/fnc/operate.rs

@@ -3,11 +3,20 @@ use crate::err::Error;
 use crate::sql::value::TryAdd;
 use crate::sql::value::TryDiv;
 use crate::sql::value::TryMul;
+use crate::sql::value::TryNeg;
 use crate::sql::value::TryPow;
 use crate::sql::value::TrySub;
 use crate::sql::value::Value;
 use crate::sql::Expression;
 
+pub fn neg(a: Value) -> Result<Value, Error> {
+	a.try_neg()
+}
+
+pub fn not(a: Value) -> Result<Value, Error> {
+	super::not::not((a,))
+}
+
 pub fn or(a: Value, b: Value) -> Result<Value, Error> {
 	Ok(match a.is_truthy() {
 		true => a,

lib/src/idx/planner/tree.rs

@@ -87,27 +87,42 @@ impl<'a> TreeBuilder<'a> {
 	}
 
 	async fn eval_expression(&mut self, e: &Expression) -> Result<Node, Error> {
-		let left = self.eval_value(&e.l).await?;
+		match e {
-		let right = self.eval_value(&e.r).await?;
+			Expression::Unary {
-		let mut index_option = None;
+				..
-		if let Some(ix) = left.is_indexed_field() {
+			} => {
-			if let Some(io) = IndexOption::found(ix, &e.o, &right, e) {
+				return Err(Error::FeatureNotYetImplemented {
-				index_option = Some(io.clone());
+					feature: "unary expressions in index",
-				self.add_index(e, io);
+				});
+			}
+			Expression::Binary {
+				l,
+				o,
+				r,
+			} => {
+				let left = self.eval_value(l).await?;
+				let right = self.eval_value(r).await?;
+				let mut index_option = None;
+				if let Some(ix) = left.is_indexed_field() {
+					if let Some(io) = IndexOption::found(ix, o, &right, e) {
+						index_option = Some(io.clone());
+						self.add_index(e, io);
+					}
+				}
+				if let Some(ix) = right.is_indexed_field() {
+					if let Some(io) = IndexOption::found(ix, o, &left, e) {
+						index_option = Some(io.clone());
+						self.add_index(e, io);
+					}
+				}
+				Ok(Node::Expression {
+					index_option,
+					left: Box::new(left),
+					right: Box::new(right),
+					operator: o.to_owned(),
+				})
 			}
 		}
-		if let Some(ix) = right.is_indexed_field() {
-			if let Some(io) = IndexOption::found(ix, &e.o, &left, e) {
-				index_option = Some(io.clone());
-				self.add_index(e, io);
-			}
-		}
-		Ok(Node::Expression {
-			index_option,
-			left: Box::new(left),
-			right: Box::new(right),
-			operator: e.o.to_owned(),
-		})
 	}
 
 	fn add_index(&mut self, e: &Expression, io: IndexOption) {

lib/src/sql/cast.rs

@@ -13,6 +13,8 @@ use serde::{Deserialize, Serialize};
 use std::cmp::Ordering;
 use std::fmt;
 
+pub(crate) const TOKEN: &str = "$surrealdb::private::sql::Cast";
+
 #[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize, Hash)]
 #[serde(rename = "$surrealdb::private::sql::Cast")]
 pub struct Cast(pub Kind, pub Value);

lib/src/sql/ending.rs

@@ -1,7 +1,7 @@
 use crate::sql::comment::comment;
 use crate::sql::comment::{mightbespace, shouldbespace};
 use crate::sql::error::IResult;
-use crate::sql::operator::{assigner, operator};
+use crate::sql::operator::{assigner, binary};
 use nom::branch::alt;
 use nom::bytes::complete::tag;
 use nom::bytes::complete::tag_no_case;
@@ -15,7 +15,7 @@ use nom::sequence::preceded;
 pub fn number(i: &str) -> IResult<&str, ()> {
 	peek(alt((
 		map(multispace1, |_| ()),
-		map(operator, |_| ()),
+		map(binary, |_| ()),
 		map(assigner, |_| ()),
 		map(comment, |_| ()),
 		map(char(')'), |_| ()),
@@ -33,7 +33,7 @@ pub fn number(i: &str) -> IResult<&str, ()> {
 pub fn ident(i: &str) -> IResult<&str, ()> {
 	peek(alt((
 		map(multispace1, |_| ()),
-		map(operator, |_| ()),
+		map(binary, |_| ()),
 		map(assigner, |_| ()),
 		map(comment, |_| ()),
 		map(char(')'), |_| ()),
@@ -51,7 +51,7 @@ pub fn ident(i: &str) -> IResult<&str, ()> {
 pub fn duration(i: &str) -> IResult<&str, ()> {
 	peek(alt((
 		map(multispace1, |_| ()),
-		map(operator, |_| ()),
+		map(binary, |_| ()),
 		map(assigner, |_| ()),
 		map(comment, |_| ()),
 		map(char(')'), |_| ()),

lib/src/sql/expression.rs

@@ -2,8 +2,9 @@ use crate::ctx::Context;
 use crate::dbs::Options;
 use crate::err::Error;
 use crate::fnc;
+use crate::sql::comment::mightbespace;
 use crate::sql::error::IResult;
-use crate::sql::operator::{operator, Operator};
+use crate::sql::operator::{self, Operator};
 use crate::sql::value::{single, value, Value};
 use serde::{Deserialize, Serialize};
 use std::fmt;
@@ -11,17 +12,24 @@ use std::str;
 
 pub(crate) const TOKEN: &str = "$surrealdb::private::sql::Expression";
 
+/// Binary expressions.
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Serialize, Deserialize, Hash)]
 #[serde(rename = "$surrealdb::private::sql::Expression")]
-pub struct Expression {
+pub enum Expression {
-	pub l: Value,
+	Unary {
-	pub o: Operator,
+		o: Operator,
-	pub r: Value,
+		v: Value,
+	},
+	Binary {
+		l: Value,
+		o: Operator,
+		r: Value,
+	},
 }
 
 impl Default for Expression {
 	fn default() -> Expression {
-		Expression {
+		Expression::Binary {
 			l: Value::Null,
 			o: Operator::default(),
 			r: Value::Null,
@@ -30,9 +38,9 @@ impl Default for Expression {
 }
 
 impl Expression {
-	/// Create a new expression
+	/// Create a new binary expression
 	pub(crate) fn new(l: Value, o: Operator, r: Value) -> Self {
-		Self {
+		Self::Binary {
 			l,
 			o,
 			r,
@@ -40,29 +48,67 @@ impl Expression {
 	}
 	/// Augment an existing expression
 	fn augment(mut self, l: Value, o: Operator) -> Self {
-		if o.precedence() >= self.o.precedence() {
+		match &mut self {
-			match self.l {
+			Self::Binary {
+				l: left,
+				o: op,
+				..
+			} if o.precedence() >= op.precedence() => match left {
 				Value::Expression(x) => {
-					self.l = x.augment(l, o).into();
+					*x.as_mut() = std::mem::take(x).augment(l, o);
 					self
 				}
 				_ => {
-					self.l = Self::new(l, o, self.l).into();
+					*left = Self::new(l, o, std::mem::take(left)).into();
 					self
 				}
+			},
+			e => {
+				let r = Value::from(std::mem::take(e));
+				Self::new(l, o, r)
 			}
-		} else {
-			let r = Value::from(self);
-			Self::new(l, o, r)
 		}
 	}
 }
 
 impl Expression {
+	pub(crate) fn writeable(&self) -> bool {
+		match self {
+			Self::Unary {
+				v,
+				..
+			} => v.writeable(),
+			Self::Binary {
+				l,
+				r,
+				..
+			} => l.writeable() || r.writeable(),
+		}
+	}
+
 	/// Process this type returning a computed simple Value
 	pub(crate) async fn compute(&self, ctx: &Context<'_>, opt: &Options) -> Result<Value, Error> {
-		let l = self.l.compute(ctx, opt).await?;
+		let (l, o, r) = match self {
-		match self.o {
+			Self::Unary {
+				o,
+				v,
+			} => {
+				let operand = v.compute(ctx, opt).await?;
+				return match o {
+					Operator::Neg => fnc::operate::neg(operand),
+					Operator::Not => fnc::operate::not(operand),
+					op => unreachable!("{op:?} is not a unary op"),
+				};
+			}
+			Self::Binary {
+				l,
+				o,
+				r,
+			} => (l, o, r),
+		};
+
+		let l = l.compute(ctx, opt).await?;
+		match o {
 			Operator::Or => {
 				if let true = l.is_truthy() {
 					return Ok(l);
@@ -85,8 +131,8 @@ impl Expression {
 			}
 			_ => {} // Continue
 		}
-		let r = self.r.compute(ctx, opt).await?;
+		let r = r.compute(ctx, opt).await?;
-		match self.o {
+		match o {
 			Operator::Or => fnc::operate::or(l, r),
 			Operator::And => fnc::operate::and(l, r),
 			Operator::Tco => fnc::operate::tco(l, r),
@@ -129,13 +175,36 @@ impl Expression {
 
 impl fmt::Display for Expression {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-		write!(f, "{} {} {}", self.l, self.o, self.r)
+		match self {
+			Self::Unary {
+				o,
+				v,
+			} => write!(f, "{o}{v}"),
+			Self::Binary {
+				l,
+				o,
+				r,
+			} => write!(f, "{l} {o} {r}"),
+		}
 	}
 }
 
-pub fn expression(i: &str) -> IResult<&str, Expression> {
+pub fn unary(i: &str) -> IResult<&str, Expression> {
+	let (i, o) = operator::unary(i)?;
+	let (i, _) = mightbespace(i)?;
+	let (i, v) = single(i)?;
+	Ok((
+		i,
+		Expression::Unary {
+			o,
+			v,
+		},
+	))
+}
+
+pub fn binary(i: &str) -> IResult<&str, Expression> {
 	let (i, l) = single(i)?;
-	let (i, o) = operator(i)?;
+	let (i, o) = operator::binary(i)?;
 	let (i, r) = value(i)?;
 	let v = match r {
 		Value::Expression(r) => r.augment(l, o),
@@ -152,7 +221,7 @@ mod tests {
 	#[test]
 	fn expression_statement() {
 		let sql = "true AND false";
-		let res = expression(sql);
+		let res = binary(sql);
 		assert!(res.is_ok());
 		let out = res.unwrap().1;
 		assert_eq!("true AND false", format!("{}", out));
@@ -161,7 +230,7 @@ mod tests {
 	#[test]
 	fn expression_left_opened() {
 		let sql = "3 * 3 * 3 = 27";
-		let res = expression(sql);
+		let res = binary(sql);
 		assert!(res.is_ok());
 		let out = res.unwrap().1;
 		assert_eq!("3 * 3 * 3 = 27", format!("{}", out));
@@ -170,7 +239,7 @@ mod tests {
 	#[test]
 	fn expression_left_closed() {
 		let sql = "(3 * 3 * 3) = 27";
-		let res = expression(sql);
+		let res = binary(sql);
 		assert!(res.is_ok());
 		let out = res.unwrap().1;
 		assert_eq!("(3 * 3 * 3) = 27", format!("{}", out));
@@ -179,7 +248,7 @@ mod tests {
 	#[test]
 	fn expression_right_opened() {
 		let sql = "27 = 3 * 3 * 3";
-		let res = expression(sql);
+		let res = binary(sql);
 		assert!(res.is_ok());
 		let out = res.unwrap().1;
 		assert_eq!("27 = 3 * 3 * 3", format!("{}", out));
@@ -188,7 +257,7 @@ mod tests {
 	#[test]
 	fn expression_right_closed() {
 		let sql = "27 = (3 * 3 * 3)";
-		let res = expression(sql);
+		let res = binary(sql);
 		assert!(res.is_ok());
 		let out = res.unwrap().1;
 		assert_eq!("27 = (3 * 3 * 3)", format!("{}", out));
@@ -197,7 +266,7 @@ mod tests {
 	#[test]
 	fn expression_both_opened() {
 		let sql = "3 * 3 * 3 = 3 * 3 * 3";
-		let res = expression(sql);
+		let res = binary(sql);
 		assert!(res.is_ok());
 		let out = res.unwrap().1;
 		assert_eq!("3 * 3 * 3 = 3 * 3 * 3", format!("{}", out));
@@ -206,9 +275,27 @@ mod tests {
 	#[test]
 	fn expression_both_closed() {
 		let sql = "(3 * 3 * 3) = (3 * 3 * 3)";
-		let res = expression(sql);
+		let res = binary(sql);
 		assert!(res.is_ok());
 		let out = res.unwrap().1;
 		assert_eq!("(3 * 3 * 3) = (3 * 3 * 3)", format!("{}", out));
 	}
+
+	#[test]
+	fn expression_unary() {
+		let sql = "-a";
+		let res = unary(sql);
+		assert!(res.is_ok());
+		let out = res.unwrap().1;
+		assert_eq!(sql, format!("{}", out));
+	}
+
+	#[test]
+	fn expression_with_unary() {
+		let sql = "-(5) + 5";
+		let res = binary(sql);
+		assert!(res.is_ok());
+		let out = res.unwrap().1;
+		assert_eq!(sql, format!("{}", out));
+	}
 }

lib/src/sql/number.rs

@@ -16,7 +16,7 @@ use std::fmt::{self, Display, Formatter};
 use std::hash;
 use std::iter::Product;
 use std::iter::Sum;
-use std::ops;
+use std::ops::{self, Neg};
 use std::str::FromStr;
 
 pub(crate) const TOKEN: &str = "$surrealdb::private::sql::Number";
@@ -572,6 +572,18 @@ impl<'a, 'b> ops::Div<&'b Number> for &'a Number {
 	}
 }
 
+impl Neg for Number {
+	type Output = Self;
+
+	fn neg(self) -> Self::Output {
+		match self {
+			Self::Int(n) => Number::Int(-n),
+			Self::Float(n) => Number::Float(-n),
+			Self::Decimal(n) => Number::Decimal(-n),
+		}
+	}
+}
+
 // ------------------------------
 
 impl Sum<Self> for Number {

lib/src/sql/operator.rs

@@ -11,8 +11,12 @@ use serde::{Deserialize, Serialize};
 use std::fmt;
 use std::fmt::Write;
 
+/// Binary operators.
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Serialize, Deserialize, Hash)]
 pub enum Operator {
+	//
+	Neg, // -
+	Not, // !
 	//
 	Or,  // ||
 	And, // &&
@@ -70,14 +74,14 @@ impl Operator {
 	#[inline]
 	pub fn precedence(&self) -> u8 {
 		match self {
-			Operator::Or => 1,
+			Self::Or => 1,
-			Operator::And => 2,
+			Self::And => 2,
-			Operator::Tco => 3,
+			Self::Tco => 3,
-			Operator::Nco => 4,
+			Self::Nco => 4,
-			Operator::Sub => 6,
+			Self::Sub => 6,
-			Operator::Add => 7,
+			Self::Add => 7,
-			Operator::Mul => 8,
+			Self::Mul => 8,
-			Operator::Div => 9,
+			Self::Div => 9,
 			_ => 5,
 		}
 	}
@@ -86,6 +90,8 @@ impl Operator {
 impl fmt::Display for Operator {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		match self {
+			Self::Neg => f.write_str("-"),
+			Self::Not => f.write_str("!"),
 			Self::Or => f.write_str("OR"),
 			Self::And => f.write_str("AND"),
 			Self::Tco => f.write_str("?:"),
@@ -143,11 +149,23 @@ pub fn assigner(i: &str) -> IResult<&str, Operator> {
 	))(i)
 }
 
-pub fn operator(i: &str) -> IResult<&str, Operator> {
+pub fn unary(i: &str) -> IResult<&str, Operator> {
-	alt((symbols, phrases))(i)
+	unary_symbols(i)
 }
 
-pub fn symbols(i: &str) -> IResult<&str, Operator> {
+pub fn unary_symbols(i: &str) -> IResult<&str, Operator> {
+	let (i, _) = mightbespace(i)?;
+	let (i, v) =
+		alt((alt((map(tag("-"), |_| Operator::Neg), map(tag("!"), |_| Operator::Not))),))(i)?;
+	let (i, _) = mightbespace(i)?;
+	Ok((i, v))
+}
+
+pub fn binary(i: &str) -> IResult<&str, Operator> {
+	alt((binary_symbols, binary_phrases))(i)
+}
+
+pub fn binary_symbols(i: &str) -> IResult<&str, Operator> {
 	let (i, _) = mightbespace(i)?;
 	let (i, v) = alt((
 		alt((
@@ -203,7 +221,7 @@ pub fn symbols(i: &str) -> IResult<&str, Operator> {
 	Ok((i, v))
 }
 
-pub fn phrases(i: &str) -> IResult<&str, Operator> {
+pub fn binary_phrases(i: &str) -> IResult<&str, Operator> {
 	let (i, _) = shouldbespace(i)?;
 	let (i, v) = alt((
 		alt((

lib/src/sql/test.rs

@@ -1,5 +1,5 @@
 use crate::sql::array::{array, Array};
-use crate::sql::expression::{expression, Expression};
+use crate::sql::expression::{binary, Expression};
 use crate::sql::idiom::{idiom, Idiom};
 use crate::sql::param::{param, Param};
 use crate::sql::script::{script, Script};
@@ -48,6 +48,6 @@ impl Parse<Self> for Thing {
 
 impl Parse<Self> for Expression {
 	fn parse(val: &str) -> Self {
-		expression(val).unwrap().1
+		binary(val).unwrap().1
 	}
 }

lib/src/sql/value/serde/ser/expression/mod.rs

@@ -19,29 +19,104 @@ impl ser::Serializer for Serializer {
 	type SerializeTupleStruct = Impossible<Expression, Error>;
 	type SerializeTupleVariant = Impossible<Expression, Error>;
 	type SerializeMap = Impossible<Expression, Error>;
-	type SerializeStruct = SerializeExpression;
+	type SerializeStruct = Impossible<Expression, Error>;
-	type SerializeStructVariant = Impossible<Expression, Error>;
+	type SerializeStructVariant = SerializeExpression;
 
-	const EXPECTED: &'static str = "a struct `Expression`";
+	const EXPECTED: &'static str = "an enum `Expression`";
 
 	#[inline]
-	fn serialize_struct(
+	fn serialize_struct_variant(
 		self,
-		_name: &'static str,
+		name: &'static str,
+		_variant_index: u32,
+		variant: &'static str,
 		_len: usize,
-	) -> Result<Self::SerializeStruct, Error> {
+	) -> Result<Self::SerializeStructVariant, Self::Error> {
-		Ok(SerializeExpression::default())
+		debug_assert_eq!(name, crate::sql::expression::TOKEN);
+		match variant {
+			"Unary" => Ok(SerializeExpression::Unary(Default::default())),
+			"Binary" => Ok(SerializeExpression::Binary(Default::default())),
+			_ => Err(Error::custom(format!("unexpected `Expression::{name}`"))),
+		}
+	}
+}
+
+pub(super) enum SerializeExpression {
+	Unary(SerializeUnary),
+	Binary(SerializeBinary),
+}
+
+impl serde::ser::SerializeStructVariant for SerializeExpression {
+	type Ok = Expression;
+	type Error = Error;
+
+	fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), Error>
+	where
+		T: ?Sized + Serialize,
+	{
+		match self {
+			Self::Unary(unary) => unary.serialize_field(key, value),
+			Self::Binary(binary) => binary.serialize_field(key, value),
+		}
+	}
+
+	fn end(self) -> Result<Self::Ok, Error> {
+		match self {
+			Self::Unary(unary) => unary.end(),
+			Self::Binary(binary) => binary.end(),
+		}
 	}
 }
 
 #[derive(Default)]
-pub(super) struct SerializeExpression {
+pub(super) struct SerializeUnary {
+	o: Option<Operator>,
+	v: Option<Value>,
+}
+
+impl serde::ser::SerializeStructVariant for SerializeUnary {
+	type Ok = Expression;
+	type Error = Error;
+
+	fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), Error>
+	where
+		T: ?Sized + Serialize,
+	{
+		match key {
+			"o" => {
+				self.o = Some(value.serialize(ser::operator::Serializer.wrap())?);
+			}
+			"v" => {
+				self.v = Some(value.serialize(ser::value::Serializer.wrap())?);
+			}
+			key => {
+				return Err(Error::custom(format!(
+					"unexpected field `Expression::Unary{{{key}}}`"
+				)));
+			}
+		}
+		Ok(())
+	}
+
+	fn end(self) -> Result<Self::Ok, Error> {
+		match (self.o, self.v) {
+			(Some(o), Some(v)) => Ok(Expression::Unary {
+				o,
+				v,
+			}),
+			_ => Err(Error::custom("`Expression::Unary` missing required field(s)")),
+		}
+	}
+}
+
+#[derive(Default)]
+pub(super) struct SerializeBinary {
 	l: Option<Value>,
 	o: Option<Operator>,
 	r: Option<Value>,
 }
 
-impl serde::ser::SerializeStruct for SerializeExpression {
+impl serde::ser::SerializeStructVariant for SerializeBinary {
 	type Ok = Expression;
 	type Error = Error;
 
@@ -60,7 +135,9 @@ impl serde::ser::SerializeStruct for SerializeExpression {
 				self.r = Some(value.serialize(ser::value::Serializer.wrap())?);
 			}
 			key => {
-				return Err(Error::custom(format!("unexpected field `Expression::{key}`")));
+				return Err(Error::custom(format!(
+					"unexpected field `Expression::Binary{{{key}}}`"
+				)));
 			}
 		}
 		Ok(())
@@ -68,12 +145,12 @@ impl serde::ser::SerializeStruct for SerializeExpression {
 
 	fn end(self) -> Result<Self::Ok, Error> {
 		match (self.l, self.o, self.r) {
-			(Some(l), Some(o), Some(r)) => Ok(Expression {
+			(Some(l), Some(o), Some(r)) => Ok(Expression::Binary {
 				l,
 				o,
 				r,
 			}),
-			_ => Err(Error::custom("`Expression` missing required field(s)")),
+			_ => Err(Error::custom("`Expression::Binary` missing required field(s)")),
 		}
 	}
 }
@@ -90,9 +167,19 @@ mod tests {
 		assert_eq!(expression, serialized);
 	}
 
+	#[test]
+	fn unary() {
+		let expression = Expression::Unary {
+			o: Operator::Not,
+			v: "Bar".into(),
+		};
+		let serialized = expression.serialize(Serializer.wrap()).unwrap();
+		assert_eq!(expression, serialized);
+	}
+
 	#[test]
 	fn foo_equals_bar() {
-		let expression = Expression {
+		let expression = Expression::Binary {
 			l: "foo".into(),
 			o: Operator::Equal,
 			r: "Bar".into(),

lib/src/sql/value/serde/ser/operator/mod.rs

@@ -28,6 +28,8 @@ impl ser::Serializer for Serializer {
 		variant: &'static str,
 	) -> Result<Self::Ok, Error> {
 		match variant {
+			"Neg" => Ok(Operator::Neg),
+			"Not" => Ok(Operator::Not),
 			"Or" => Ok(Operator::Or),
 			"And" => Ok(Operator::And),
 			"Tco" => Ok(Operator::Tco),

lib/src/sql/value/serde/ser/value/mod.rs

@@ -20,6 +20,7 @@ use crate::sql::Table;
 use crate::sql::Uuid;
 use map::SerializeValueMap;
 use rust_decimal::Decimal;
+use ser::cast::SerializeCast;
 use ser::edges::SerializeEdges;
 use ser::expression::SerializeExpression;
 use ser::function::SerializeFunction;
@@ -60,7 +61,7 @@ impl ser::Serializer for Serializer {
 
 	type SerializeSeq = SerializeArray;
 	type SerializeTuple = SerializeArray;
-	type SerializeTupleStruct = SerializeArray;
+	type SerializeTupleStruct = SerializeTupleStruct;
 	type SerializeTupleVariant = SerializeTupleVariant;
 	type SerializeMap = SerializeMap;
 	type SerializeStruct = SerializeStruct;
@@ -299,10 +300,13 @@ impl ser::Serializer for Serializer {
 
 	fn serialize_tuple_struct(
 		self,
-		_name: &'static str,
+		name: &'static str,
-		len: usize,
+		_len: usize,
 	) -> Result<Self::SerializeTupleStruct, Error> {
-		self.serialize_seq(Some(len))
+		match name {
+			sql::cast::TOKEN => Ok(SerializeTupleStruct::Cast(Default::default())),
+			_ => Ok(SerializeTupleStruct::Array(Default::default())),
+		}
 	}
 
 	fn serialize_tuple_variant(
@@ -347,7 +351,6 @@ impl ser::Serializer for Serializer {
 	) -> Result<Self::SerializeStruct, Error> {
 		Ok(match name {
 			sql::thing::TOKEN => SerializeStruct::Thing(Default::default()),
-			sql::expression::TOKEN => SerializeStruct::Expression(Default::default()),
 			sql::edges::TOKEN => SerializeStruct::Edges(Default::default()),
 			sql::range::TOKEN => SerializeStruct::Range(Default::default()),
 			_ => SerializeStruct::Unknown(Default::default()),
@@ -356,18 +359,27 @@ impl ser::Serializer for Serializer {
 
 	fn serialize_struct_variant(
 		self,
-		_name: &'static str,
+		name: &'static str,
 		_variant_index: u32,
 		variant: &'static str,
 		_len: usize,
 	) -> Result<Self::SerializeStructVariant, Error> {
-		Ok(SerializeStructVariant {
+		Ok(if name == sql::expression::TOKEN {
-			name: String::from(variant),
+			SerializeStructVariant::Expression(match variant {
-			map: Object::default(),
+				"Unary" => SerializeExpression::Unary(Default::default()),
+				"Binary" => SerializeExpression::Binary(Default::default()),
+				_ => return Err(Error::custom(format!("unexpected `Expression::{name}`"))),
+			})
+		} else {
+			SerializeStructVariant::Object {
+				name: String::from(variant),
+				map: Object::default(),
+			}
 		})
 	}
 }
 
+#[derive(Default)]
 pub(super) struct SerializeArray(vec::SerializeValueVec);
 
 impl serde::ser::SerializeSeq for SerializeArray {
@@ -452,6 +464,33 @@ pub(super) enum SerializeTupleVariant {
 	},
 }
 
+pub(super) enum SerializeTupleStruct {
+	Cast(SerializeCast),
+	Array(SerializeArray),
+}
+
+impl serde::ser::SerializeTupleStruct for SerializeTupleStruct {
+	type Ok = Value;
+	type Error = Error;
+
+	fn serialize_field<T>(&mut self, value: &T) -> Result<(), Error>
+	where
+		T: ?Sized + Serialize,
+	{
+		match self {
+			Self::Cast(cast) => cast.serialize_field(value),
+			Self::Array(array) => array.serialize_field(value),
+		}
+	}
+
+	fn end(self) -> Result<Value, Error> {
+		match self {
+			Self::Cast(cast) => Ok(Value::Cast(Box::new(cast.end()?))),
+			Self::Array(array) => Ok(serde::ser::SerializeTupleStruct::end(array)?),
+		}
+	}
+}
+
 impl serde::ser::SerializeTupleVariant for SerializeTupleVariant {
 	type Ok = Value;
 	type Error = Error;
@@ -461,9 +500,9 @@ impl serde::ser::SerializeTupleVariant for SerializeTupleVariant {
 		T: ?Sized + Serialize,
 	{
 		match self {
-			SerializeTupleVariant::Model(model) => model.serialize_field(value),
+			Self::Model(model) => model.serialize_field(value),
-			SerializeTupleVariant::Function(function) => function.serialize_field(value),
+			Self::Function(function) => function.serialize_field(value),
-			SerializeTupleVariant::Unknown {
+			Self::Unknown {
 				ref mut fields,
 				..
 			} => fields.serialize_element(value),
@@ -472,11 +511,9 @@ impl serde::ser::SerializeTupleVariant for SerializeTupleVariant {
 
 	fn end(self) -> Result<Value, Error> {
 		match self {
-			SerializeTupleVariant::Model(model) => Ok(Value::Model(model.end()?)),
+			Self::Model(model) => Ok(Value::Model(model.end()?)),
-			SerializeTupleVariant::Function(function) => {
+			Self::Function(function) => Ok(Value::Function(Box::new(function.end()?))),
-				Ok(Value::Function(Box::new(function.end()?)))
+			Self::Unknown {
-			}
-			SerializeTupleVariant::Unknown {
 				variant,
 				fields,
 			} => Ok(map! {
@@ -489,7 +526,6 @@ impl serde::ser::SerializeTupleVariant for SerializeTupleVariant {
 
 pub(super) enum SerializeStruct {
 	Thing(SerializeThing),
-	Expression(SerializeExpression),
 	Edges(SerializeEdges),
 	Range(SerializeRange),
 	Unknown(SerializeValueMap),
@@ -504,28 +540,29 @@ impl serde::ser::SerializeStruct for SerializeStruct {
 		T: ?Sized + Serialize,
 	{
 		match self {
-			SerializeStruct::Thing(thing) => thing.serialize_field(key, value),
+			Self::Thing(thing) => thing.serialize_field(key, value),
-			SerializeStruct::Expression(expr) => expr.serialize_field(key, value),
+			Self::Edges(edges) => edges.serialize_field(key, value),
-			SerializeStruct::Edges(edges) => edges.serialize_field(key, value),
+			Self::Range(range) => range.serialize_field(key, value),
-			SerializeStruct::Range(range) => range.serialize_field(key, value),
+			Self::Unknown(map) => map.serialize_entry(key, value),
-			SerializeStruct::Unknown(map) => map.serialize_entry(key, value),
 		}
 	}
 
 	fn end(self) -> Result<Value, Error> {
 		match self {
-			SerializeStruct::Thing(thing) => Ok(Value::Thing(thing.end()?)),
+			Self::Thing(thing) => Ok(Value::Thing(thing.end()?)),
-			SerializeStruct::Expression(expr) => Ok(Value::Expression(Box::new(expr.end()?))),
+			Self::Edges(edges) => Ok(Value::Edges(Box::new(edges.end()?))),
-			SerializeStruct::Edges(edges) => Ok(Value::Edges(Box::new(edges.end()?))),
+			Self::Range(range) => Ok(Value::Range(Box::new(range.end()?))),
-			SerializeStruct::Range(range) => Ok(Value::Range(Box::new(range.end()?))),
+			Self::Unknown(map) => Ok(Value::Object(Object(map.end()?))),
-			SerializeStruct::Unknown(map) => Ok(Value::Object(Object(map.end()?))),
 		}
 	}
 }
 
-pub(super) struct SerializeStructVariant {
+pub(super) enum SerializeStructVariant {
-	name: String,
+	Expression(SerializeExpression),
-	map: Object,
+	Object {
+		name: String,
+		map: Object,
+	},
 }
 
 impl serde::ser::SerializeStructVariant for SerializeStructVariant {
@@ -536,16 +573,32 @@ impl serde::ser::SerializeStructVariant for SerializeStructVariant {
 	where
 		T: ?Sized + Serialize,
 	{
-		self.map.0.insert(String::from(key), value.serialize(Serializer.wrap())?);
+		match self {
-		Ok(())
+			Self::Expression(expression) => expression.serialize_field(key, value),
+			Self::Object {
+				map,
+				..
+			} => {
+				map.0.insert(String::from(key), value.serialize(Serializer.wrap())?);
+				Ok(())
+			}
+		}
 	}
 
 	fn end(self) -> Result<Value, Error> {
-		let mut object = Object::default();
+		match self {
+			Self::Expression(expression) => Ok(Value::from(expression.end()?)),
+			Self::Object {
+				name,
+				map,
+			} => {
+				let mut object = Object::default();
 
-		object.insert(self.name, Value::Object(self.map));
+				object.insert(name, Value::Object(map));
 
-		Ok(Value::Object(object))
+				Ok(Value::Object(object))
+			}
+		}
 	}
 }
 
@@ -825,7 +878,7 @@ mod tests {
 
 	#[test]
 	fn expression() {
-		let expression = Box::new(Expression {
+		let expression = Box::new(Expression::Binary {
 			l: "foo".into(),
 			o: Operator::Equal,
 			r: "Bar".into(),

lib/src/sql/value/serde/ser/value/vec.rs

@@ -38,6 +38,7 @@ impl ser::Serializer for Serializer {
 	}
 }
 
+#[derive(Default)]
 pub struct SerializeValueVec(pub Vec<Value>);
 
 impl serde::ser::SerializeSeq for SerializeValueVec {

lib/src/sql/value/value.rs

@@ -15,7 +15,7 @@ use crate::sql::datetime::{datetime, Datetime};
 use crate::sql::duration::{duration, Duration};
 use crate::sql::edges::{edges, Edges};
 use crate::sql::error::IResult;
-use crate::sql::expression::{expression, Expression};
+use crate::sql::expression::{binary, unary, Expression};
 use crate::sql::fmt::{Fmt, Pretty};
 use crate::sql::function::{self, function, Function};
 use crate::sql::future::{future, Future};
@@ -58,6 +58,7 @@ use std::collections::BTreeMap;
 use std::collections::HashMap;
 use std::fmt::{self, Display, Formatter, Write};
 use std::ops::Deref;
+use std::ops::Neg;
 use std::str::FromStr;
 
 static MATCHER: Lazy<SkimMatcherV2> = Lazy::new(|| SkimMatcherV2::default().ignore_case());
@@ -2477,7 +2478,7 @@ impl Value {
 			Value::Object(v) => v.iter().any(|(_, v)| v.writeable()),
 			Value::Function(v) => v.is_custom() || v.args().iter().any(Value::writeable),
 			Value::Subquery(v) => v.writeable(),
-			Value::Expression(v) => v.l.writeable() || v.r.writeable(),
+			Value::Expression(v) => v.writeable(),
 			_ => false,
 		}
 	}
@@ -2658,9 +2659,24 @@ impl TryPow for Value {
 
 // ------------------------------
 
-/// Parse any `Value` including binary expressions
+pub(crate) trait TryNeg<Rhs = Self> {
+	type Output;
+	fn try_neg(self) -> Result<Self::Output, Error>;
+}
+
+impl TryNeg for Value {
+	type Output = Self;
+	fn try_neg(self) -> Result<Self, Error> {
+		match self {
+			Self::Number(n) if !matches!(n, Number::Int(i64::MIN)) => Ok(Self::Number(n.neg())),
+			v => Err(Error::TryNeg(v.to_string())),
+		}
+	}
+}
+
+/// Parse any `Value` including expressions
 pub fn value(i: &str) -> IResult<&str, Value> {
-	alt((map(expression, Value::from), single))(i)
+	alt((map(binary, Value::from), single))(i)
 }
 
 /// Parse any `Value` excluding binary expressions
@@ -2684,8 +2700,11 @@ pub fn single(i: &str) -> IResult<&str, Value> {
 			map(future, Value::from),
 			map(unique, Value::from),
 			map(number, Value::from),
+			map(unary, Value::from),
 			map(object, Value::from),
 			map(array, Value::from),
+		)),
+		alt((
 			map(block, Value::from),
 			map(param, Value::from),
 			map(regex, Value::from),
@@ -2702,7 +2721,8 @@ pub fn single(i: &str) -> IResult<&str, Value> {
 pub fn select(i: &str) -> IResult<&str, Value> {
 	alt((
 		alt((
-			map(expression, Value::from),
+			map(unary, Value::from),
+			map(binary, Value::from),
 			map(tag_no_case("NONE"), |_| Value::None),
 			map(tag_no_case("NULL"), |_| Value::Null),
 			map(tag_no_case("true"), |_| Value::Bool(true)),

lib/tests/select.rs

@@ -65,6 +65,64 @@ async fn select_field_value() -> Result<(), Error> {
 	Ok(())
 }
 
+#[tokio::test]
+async fn select_expression_value() -> Result<(), Error> {
+	let sql = "
+		CREATE thing:a SET number = 5, boolean = true;
+		CREATE thing:b SET number = -5, boolean = false;
+		SELECT VALUE -number FROM thing;
+		SELECT VALUE !boolean FROM thing;
+	";
+	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::parse(
+		"[
+			{
+				boolean: true,
+				id: thing:a,
+				number: 5
+			}
+		]",
+	);
+	assert_eq!(tmp, val);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::parse(
+		"[
+			{
+				boolean: false,
+				id: thing:b,
+				number: -5
+			}
+		]",
+	);
+	assert_eq!(tmp, val);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::parse(
+		"[
+			-5,
+			5,
+		]",
+	);
+	assert_eq!(tmp, val);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::parse(
+		"[
+			false,
+			true
+		]",
+	);
+	assert_eq!(tmp, val);
+	//
+	Ok(())
+}
+
 #[tokio::test]
 async fn select_writeable_subqueries() -> Result<(), Error> {
 	let sql = "