Add support for constants, and add math constants (#1263)

lib/src/sql/constant.rs

@@ -0,0 +1,66 @@
+use crate::sql::error::IResult;
+use crate::sql::value::Value;
+use nom::branch::alt;
+use nom::bytes::complete::tag_no_case;
+use nom::combinator::map;
+
+pub fn constant(i: &str) -> IResult<&str, Value> {
+	alt((constant_math,))(i)
+}
+
+fn constant_math(i: &str) -> IResult<&str, Value> {
+	alt((
+		map(tag_no_case("math::E"), |_| std::f64::consts::E.into()),
+		map(tag_no_case("math::FRAC_1_PI"), |_| std::f64::consts::FRAC_1_PI.into()),
+		map(tag_no_case("math::FRAC_1_SQRT_2"), |_| std::f64::consts::FRAC_1_SQRT_2.into()),
+		map(tag_no_case("math::FRAC_2_PI"), |_| std::f64::consts::FRAC_2_PI.into()),
+		map(tag_no_case("math::FRAC_2_SQRT_PI"), |_| std::f64::consts::FRAC_2_SQRT_PI.into()),
+		map(tag_no_case("math::FRAC_PI_2"), |_| std::f64::consts::FRAC_PI_2.into()),
+		map(tag_no_case("math::FRAC_PI_3"), |_| std::f64::consts::FRAC_PI_3.into()),
+		map(tag_no_case("math::FRAC_PI_4"), |_| std::f64::consts::FRAC_PI_4.into()),
+		map(tag_no_case("math::FRAC_PI_6"), |_| std::f64::consts::FRAC_PI_6.into()),
+		map(tag_no_case("math::FRAC_PI_8"), |_| std::f64::consts::FRAC_PI_8.into()),
+		map(tag_no_case("math::LN_10"), |_| std::f64::consts::LN_10.into()),
+		map(tag_no_case("math::LN_2"), |_| std::f64::consts::LN_2.into()),
+		map(tag_no_case("math::LOG10_2"), |_| std::f64::consts::LOG10_2.into()),
+		map(tag_no_case("math::LOG10_E"), |_| std::f64::consts::LOG10_E.into()),
+		map(tag_no_case("math::LOG2_10"), |_| std::f64::consts::LOG2_10.into()),
+		map(tag_no_case("math::LOG2_E"), |_| std::f64::consts::LOG2_E.into()),
+		map(tag_no_case("math::PI"), |_| std::f64::consts::PI.into()),
+		map(tag_no_case("math::SQRT_2"), |_| std::f64::consts::SQRT_2.into()),
+		map(tag_no_case("math::TAU"), |_| std::f64::consts::TAU.into()),
+	))(i)
+}
+
+#[cfg(test)]
+mod tests {
+
+	use super::*;
+
+	#[test]
+	fn constant_lowercase() {
+		let sql = "math::pi";
+		let res = constant(sql);
+		assert!(res.is_ok());
+		let out = res.unwrap().1;
+		assert_eq!(out, Value::from(std::f64::consts::PI));
+	}
+
+	#[test]
+	fn constant_uppercase() {
+		let sql = "MATH::PI";
+		let res = constant(sql);
+		assert!(res.is_ok());
+		let out = res.unwrap().1;
+		assert_eq!(out, Value::from(std::f64::consts::PI));
+	}
+
+	#[test]
+	fn constant_mixedcase() {
+		let sql = "math::PI";
+		let res = constant(sql);
+		assert!(res.is_ok());
+		let out = res.unwrap().1;
+		assert_eq!(out, Value::from(std::f64::consts::PI));
+	}
+}

lib/src/sql/mod.rs

@@ -4,6 +4,7 @@ pub(crate) mod base;
 pub(crate) mod comment;
 pub(crate) mod common;
 pub(crate) mod cond;
+pub(crate) mod constant;
 pub(crate) mod data;
 pub(crate) mod datetime;
 pub(crate) mod dir;

lib/src/sql/value/value.rs

@@ -7,6 +7,7 @@ use crate::dbs::Transaction;
 use crate::err::Error;
 use crate::sql::array::{array, Array};
 use crate::sql::common::commas;
+use crate::sql::constant::constant;
 use crate::sql::datetime::{datetime, Datetime};
 use crate::sql::duration::{duration, Duration};
 use crate::sql::edges::{edges, Edges};
@@ -1261,6 +1262,7 @@ pub fn single(i: &str) -> IResult<&str, Value> {
 		alt((
 			map(subquery, Value::from),
 			map(function, Value::from),
+			map(constant, Value::from),
 			map(datetime, Value::from),
 			map(duration, Value::from),
 			map(geometry, Value::from),
@@ -1290,6 +1292,7 @@ pub fn select(i: &str) -> IResult<&str, Value> {
 			map(expression, Value::from),
 			map(subquery, Value::from),
 			map(function, Value::from),
+			map(constant, Value::from),
 			map(datetime, Value::from),
 			map(duration, Value::from),
 			map(geometry, Value::from),
@@ -1313,6 +1316,7 @@ pub fn what(i: &str) -> IResult<&str, Value> {
 	alt((
 		map(subquery, Value::from),
 		map(function, Value::from),
+		map(constant, Value::from),
 		map(param, Value::from),
 		map(model, Value::from),
 		map(edges, Value::from),