Merge pull request #195 from Qrlew/implement_sign

Implement sign
Qrlew · Nov 20, 2023 · 0ad6eae · 0ad6eae
2 parents c322287 + 05fd357
commit 0ad6eae
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Showing 7 changed files with 100 additions and 5 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [0.5.2] - 2023-11-19
 ## Added
 - `CEIL`, `ROUND`, `FLOOR`and `TRUNC` funtions [#192](https://github.com/Qrlew/qrlew/issues/192)
+- `SIGN` funtion [#194](https://github.com/Qrlew/qrlew/issues/194)
 - SD is acceptable as DP compilation
 
 ## [0.5.1] - 2023-11-19

diff --git a/src/data_type/function.rs b/src/data_type/function.rs
@@ -1838,6 +1838,14 @@ pub fn trunc() -> impl Function {
     )
 }
 
+// Sign function
+pub fn sign() -> impl Function {
+    PartitionnedMonotonic::univariate(
+        data_type::Float::default(),
+        |a| if a == 0. {0} else if a < 0. {-1} else {1}
+    )
+}
+
 /*
 Aggregation functions
  */
@@ -3557,4 +3565,24 @@ mod tests {
         println!("im({}) = {}", set, im);
         assert!(im == DataType::boolean_value(true));
     }
+
+    #[test]
+    fn test_sign() {
+        println!("\nTest sign");
+        let fun = sign();
+        println!("type = {}", fun);
+        println!("domain = {}", fun.domain());
+        println!("co_domain = {}", fun.co_domain());
+        println!("data_type = {}", fun.data_type());
+
+        let set = DataType::float_interval(-5., 5.);
+        let im = fun.super_image(&set).unwrap();
+        println!("im({}) = {}", set, im);
+        assert!(im == DataType::integer_interval(-1, 1));
+
+        let set = DataType::float_value(0.);
+        let im = fun.super_image(&set).unwrap();
+        println!("im({}) = {}", set, im);
+        assert!(im == DataType::integer_value(0));
+    }
 }
diff --git a/src/expr/function.rs b/src/expr/function.rs
@@ -33,6 +33,7 @@ pub enum Function {
     BitwiseXor,
     InList,
     Coalesce,
+    Sign,
     // Functions
     Exp,
     Ln,
@@ -132,6 +133,7 @@ impl Function {
             | Function::Floor
             | Function::CastAsDate
             | Function::CastAsTime
+            | Function::Sign
             // Binary Functions
             | Function::Pow
             | Function::Position
@@ -198,7 +200,8 @@ impl Function {
             | Function::CastAsDate
             | Function::CastAsTime
             | Function::Ceil
-            | Function::Floor => Arity::Unary,
+            | Function::Floor
+            | Function::Sign => Arity::Unary,
             // Binary Function
             Function::Pow
             | Function::Position
@@ -289,6 +292,7 @@ impl fmt::Display for Function {
             Function::Floor => "floor",
             Function::CastAsDate => "cast_as_date",
             Function::CastAsTime => "cast_as_time",
+            Function::Sign => "sign",
             // Binary Functions
             Function::Pow => "pow",
             Function::Position => "position",

diff --git a/src/expr/implementation.rs b/src/expr/implementation.rs
@@ -40,12 +40,12 @@ macro_rules! function_implementations {
 }
 
 // All functions:
-// Unary: Opposite, Not, Exp, Ln, Abs, Sin, Cos, CharLength, Lower, Upper, Md5, Ceil, Floor
+// Unary: Opposite, Not, Exp, Ln, Abs, Sin, Cos, CharLength, Lower, Upper, Md5, Ceil, Floor, Sign
 // Binary: Plus, Minus, Multiply, Divide, Modulo, StringConcat, Gt, Lt, GtEq, LtEq, Eq, NotEq, And, Or, Xor, BitwiseOr, BitwiseAnd, BitwiseXor, Position, Concat, Greatest, Least, Round, Trunc
 // Ternary: Case, Position
 // Nary: Concat
 function_implementations!(
-    [Opposite, Not, Exp, Ln, Log, Abs, Sin, Cos, Sqrt, Md5, Ceil, Floor],
+    [Opposite, Not, Exp, Ln, Log, Abs, Sin, Cos, Sqrt, Md5, Ceil, Floor, Sign],
     [
         Plus,
         Minus,

diff --git a/src/expr/mod.rs b/src/expr/mod.rs
@@ -286,7 +286,8 @@ impl_unary_function_constructors!(
     CastAsDate,
     CastAsTime,
     Ceil,
-    Floor
+    Floor,
+    Sign
 ); // TODO Complete that
 
 /// Implement binary function constructors
@@ -2998,4 +2999,52 @@ mod tests {
             DataType::boolean_value(false)
         );
     }
+
+    #[test]
+    fn test_sign() {
+        println!("sign");
+        let expression = Expr::sign(
+            Expr::col("col1".to_string())
+        );
+        println!("expression = {}", expression);
+        println!("expression domain = {}", expression.domain());
+        println!("expression co domain = {}", expression.co_domain());
+        println!("expression data type = {}", expression.data_type());
+
+        let set = DataType::structured([
+            ("col1", DataType::float_interval(-10., 1.)),
+        ]);
+        println!(
+            "expression super image = {}",
+            expression.super_image(&set).unwrap()
+        );
+        assert_eq!(
+            expression.super_image(&set).unwrap(),
+            DataType::integer_interval(-1, 1)
+        );
+
+        let set = DataType::structured([
+            ("col1", DataType::integer_min(-0)),
+        ]);
+        println!(
+            "expression super image = {}",
+            expression.super_image(&set).unwrap()
+        );
+        assert_eq!(
+            expression.super_image(&set).unwrap(),
+            DataType::integer_interval(0, 1)
+        );
+
+        let set = DataType::structured([
+            ("col1", DataType::float_min(1.)),
+        ]);
+        println!(
+            "expression super image = {}",
+            expression.super_image(&set).unwrap()
+        );
+        assert_eq!(
+            expression.super_image(&set).unwrap(),
+            DataType::integer_value(1)
+        );
+    }
 }
diff --git a/src/expr/sql.rs b/src/expr/sql.rs
@@ -186,7 +186,8 @@ impl<'a> expr::Visitor<'a, ast::Expr> for FromExprVisitor {
             | expr::function::Function::Substr
             | expr::function::Function::SubstrWithSize
             | expr::function::Function::Ceil
-            | expr::function::Function::Floor => ast::Expr::Function(ast::Function {
+            | expr::function::Function::Floor
+            | expr::function::Function::Sign => ast::Expr::Function(ast::Function {
                 name: ast::ObjectName(vec![ast::Ident::new(function.to_string())]),
                 args: arguments
                     .into_iter()
@@ -651,4 +652,15 @@ mod tests {
         println!("ast::expr = {gen_expr}");
         assert_eq!(ast_expr.to_string().to_lowercase(), gen_expr.to_string().to_lowercase());
     }
+
+    #[test]
+    fn test_sign() {
+        let str_expr = "sign(a)";
+        let ast_expr: ast::Expr = parse_expr(str_expr).unwrap();
+        let expr = Expr::try_from(&ast_expr).unwrap();
+        println!("expr = {}", expr);
+        let gen_expr = ast::Expr::from(&expr);
+        println!("ast::expr = {gen_expr}");
+        assert_eq!(ast_expr, gen_expr);
+    }
 }
diff --git a/src/sql/expr.rs b/src/sql/expr.rs
@@ -980,6 +980,7 @@ impl<'a> Visitor<'a, Result<Expr>> for TryIntoExprVisitor<'a> {
                     precision,
                 )
             }
+            "sign" => Expr::sign(flat_args[0].clone()),
             // Aggregates
             "min" => Expr::min(flat_args[0].clone()),
             "max" => Expr::max(flat_args[0].clone()),