Implement SIGN()

base/src/functions/mathematical.rs

@@ -682,4 +682,25 @@ impl Model {
         }
         CalcResult::Number((x + random() * (y - x)).floor())
     }
+
+    pub(crate) fn fn_sign(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if args.len() != 1 {
+            return CalcResult::new_args_number_error(cell);
+        }
+        let value = match self.get_number(&args[0], cell) {
+            Ok(f) => f,
+            Err(s) => return s,
+        };
+        if value.is_nan() {
+            return CalcResult::Error {
+                error: Error::NUM,
+                origin: cell,
+                message: "Invalid argument for SIGN".to_string(),
+            };
+        }
+        if value == 0.0 {
+            return CalcResult::Number(0.0);
+        }
+        CalcResult::Number(value.signum())
+    }
 }

base/src/functions/mod.rs

@@ -63,6 +63,7 @@ pub enum Function {
     Round,
     Rounddown,
     Roundup,
+    Sign,
     Sin,
     Sinh,
     Sqrt,
@@ -248,7 +249,7 @@ pub enum Function {
 }
 
 impl Function {
-    pub fn into_iter() -> IntoIter<Function, 194> {
+    pub fn into_iter() -> IntoIter<Function, 195> {
         [
             Function::And,
             Function::False,
@@ -287,6 +288,7 @@ impl Function {
             Function::Round,
             Function::Rounddown,
             Function::Roundup,
+            Function::Sign,
             Function::Sum,
             Function::Sumif,
             Function::Sumifs,
@@ -542,7 +544,7 @@ impl Function {
             "SUM" => Some(Function::Sum),
             "SUMIF" => Some(Function::Sumif),
             "SUMIFS" => Some(Function::Sumifs),
-
+            "SIGN" => Some(Function::Sign),
             // Lookup and Reference
             "CHOOSE" => Some(Function::Choose),
             "COLUMN" => Some(Function::Column),
@@ -759,6 +761,7 @@ impl fmt::Display for Function {
             Function::Sum => write!(f, "SUM"),
             Function::Sumif => write!(f, "SUMIF"),
             Function::Sumifs => write!(f, "SUMIFS"),
+            Function::Sign => write!(f, "SIGN"),
             Function::Choose => write!(f, "CHOOSE"),
             Function::Column => write!(f, "COLUMN"),
             Function::Columns => write!(f, "COLUMNS"),
@@ -991,6 +994,7 @@ impl Model {
             Function::Sum => self.fn_sum(args, cell),
             Function::Sumif => self.fn_sumif(args, cell),
             Function::Sumifs => self.fn_sumifs(args, cell),
+            Function::Sign => self.fn_sign(args, cell),
 
             // Lookup and Reference
             Function::Choose => self.fn_choose(args, cell),

base/src/test/test_math.rs

@@ -27,3 +27,31 @@ fn test_fn_sqrtpi_arguments() {
     assert_eq!(model._get_text("A1"), *"#ERROR!");
     assert_eq!(model._get_text("A2"), *"#ERROR!");
 }
+
+#[test]
+fn test_fn_sign_arguments() {
+    let mut model = new_empty_model();
+    model._set("A1", "=SIGN(-42)");
+    model._set("A2", "=SIGN(13)");
+    model._set("A3", "=SIGN(0)");
+    model._set("A4", "=SIGN()");
+    model._set("A5", "=SIGN('')");
+    model._set("A6", "=SIGN('Hello')");
+    model._set("A7", "=SIGN(1, 2)");
+    model._set("A8", "=SIGN(B8)");
+    model._set("A9", "=SIGN(4-4)");
+    model._set("A10", "=SIGN(-0.000001)");
+
+    model.evaluate();
+
+    assert_eq!(model._get_text("A1"), *"-1");
+    assert_eq!(model._get_text("A2"), *"1");
+    assert_eq!(model._get_text("A3"), *"0");
+    assert_eq!(model._get_text("A4"), *"#ERROR!");
+    assert_eq!(model._get_text("A5"), *"#ERROR!");
+    assert_eq!(model._get_text("A6"), *"#ERROR!");
+    assert_eq!(model._get_text("A7"), *"#ERROR!");
+    assert_eq!(model._get_text("A8"), *"0");
+    assert_eq!(model._get_text("A9"), *"0");
+    assert_eq!(model._get_text("A10"), *"-1");
+}

docs/src/functions/math-and-trigonometry.md

@@ -76,7 +76,7 @@ You can track the progress in this [GitHub issue](https://github.com/ironcalc/Ir
 | SECH            | <Badge type="info" text="Not implemented yet" /> | –             |
 | SERIESSUM       | <Badge type="info" text="Not implemented yet" /> | –             |
 | SEQUENCE        | <Badge type="info" text="Not implemented yet" /> | –             |
-| SIGN            | <Badge type="info" text="Not implemented yet" /> | –             |
+| SIGN            | <Badge type="tip" text="Available" /> | –             |
 | SIN             | <Badge type="tip" text="Available" />          | –             |
 | SINH            | <Badge type="tip" text="Available" />          | –             |
 | SQRT            | <Badge type="tip" text="Available" />          | –             |

docs/src/functions/math_and_trigonometry/sign.md

@@ -7,6 +7,5 @@ lang: en-US
 # SIGN
 
 ::: warning
-🚧 This function is not yet available in IronCalc.
-[Follow development here](https://github.com/ironcalc/IronCalc/labels/Functions)
+🚧 This function is implemented but currently lacks detailed documentation. For guidance, you may refer to the equivalent functionality in [Microsoft Excel documentation](https://support.microsoft.com/en-us/office/excel-functions-by-category-5f91f4e9-7b42-46d2-9bd1-63f26a86c0eb).
 :::