merge duration, mduration #44

base/src/expressions/parser/static_analysis.rs

@@ -759,6 +759,8 @@ fn get_function_args_signature(kind: &Function, arg_count: usize) -> Vec<Signatu
         Function::Nominal => args_signature_scalars(arg_count, 2, 0),
         Function::Nper => args_signature_scalars(arg_count, 3, 2),
         Function::Npv => args_signature_npv(arg_count),
+        Function::Duration => args_signature_scalars(arg_count, 5, 1),
+        Function::Mduration => args_signature_scalars(arg_count, 5, 1),
         Function::Pduration => args_signature_scalars(arg_count, 3, 0),
         Function::Pmt => args_signature_scalars(arg_count, 3, 2),
         Function::Ppmt => args_signature_scalars(arg_count, 4, 2),
@@ -1023,6 +1025,8 @@ fn static_analysis_on_function(kind: &Function, args: &[Node]) -> StaticResult {
         Function::Nominal => not_implemented(args),
         Function::Nper => not_implemented(args),
         Function::Npv => not_implemented(args),
+        Function::Duration => not_implemented(args),
+        Function::Mduration => not_implemented(args),
         Function::Pduration => not_implemented(args),
         Function::Pmt => not_implemented(args),
         Function::Ppmt => not_implemented(args),

base/src/functions/financial.rs

@@ -1339,6 +1339,114 @@ impl Model {
         CalcResult::Number(result)
     }
 
+    // DURATION(settlement, maturity, coupon, yld, freq, [basis])
+    pub(crate) fn fn_duration(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        let arg_count = args.len();
+        if !(5..=6).contains(&arg_count) {
+            return CalcResult::new_args_number_error(cell);
+        }
+        let settlement = match self.get_number_no_bools(&args[0], cell) {
+            Ok(f) => f,
+            Err(s) => return s,
+        };
+        let maturity = match self.get_number_no_bools(&args[1], cell) {
+            Ok(f) => f,
+            Err(s) => return s,
+        };
+        let coupon = match self.get_number_no_bools(&args[2], cell) {
+            Ok(f) => f,
+            Err(s) => return s,
+        };
+        let yld = match self.get_number_no_bools(&args[3], cell) {
+            Ok(f) => f,
+            Err(s) => return s,
+        };
+        let freq = match self.get_number_no_bools(&args[4], cell) {
+            Ok(f) => f.trunc() as i32,
+            Err(s) => return s,
+        };
+        let basis = if arg_count > 5 {
+            match self.get_number_no_bools(&args[5], cell) {
+                Ok(f) => f.trunc() as i32,
+                Err(s) => return s,
+            }
+        } else {
+            0
+        };
+        if settlement >= maturity || coupon < 0.0 || yld < 0.0 || !matches!(freq, 1 | 2 | 4) {
+            return CalcResult::new_error(Error::NUM, cell, "Invalid arguments".to_string());
+        }
+
+        let days_in_year = match basis {
+            0 | 2 | 4 => 360.0,
+            1 | 3 => 365.0,
+            _ => 360.0,
+        };
+        let diff_days = maturity - settlement;
+        if diff_days <= 0.0 {
+            return CalcResult::new_error(Error::NUM, cell, "Invalid arguments".to_string());
+        }
+        let yearfrac = diff_days / days_in_year;
+        let mut num_coupons = (yearfrac * freq as f64).ceil();
+        if num_coupons < 1.0 {
+            num_coupons = 1.0;
+        }
+
+        let cf = coupon * 100.0 / freq as f64;
+        let y = 1.0 + yld / freq as f64;
+        let ndiff = yearfrac * freq as f64 - num_coupons;
+        let mut dur = 0.0;
+        for t in 1..(num_coupons as i32) {
+            let tt = t as f64 + ndiff;
+            dur += tt * cf / y.powf(tt);
+        }
+        let last_t = num_coupons + ndiff;
+        dur += last_t * (cf + 100.0) / y.powf(last_t);
+
+        let mut price = 0.0;
+        for t in 1..(num_coupons as i32) {
+            let tt = t as f64 + ndiff;
+            price += cf / y.powf(tt);
+        }
+        price += (cf + 100.0) / y.powf(last_t);
+
+        if price == 0.0 {
+            return CalcResult::new_error(Error::DIV, cell, "Division by 0".to_string());
+        }
+
+        let result = (dur / price) / freq as f64;
+        CalcResult::Number(result)
+    }
+
+    // MDURATION(settlement, maturity, coupon, yld, freq, [basis])
+    pub(crate) fn fn_mduration(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        let mut res = self.fn_duration(args, cell);
+        if let CalcResult::Number(ref mut d) = res {
+            let yld = match self.get_number_no_bools(&args[3], cell) {
+                Ok(f) => f,
+                Err(_) => {
+                    return CalcResult::new_error(
+                        Error::VALUE,
+                        cell,
+                        "Invalid arguments".to_string(),
+                    )
+                }
+            };
+            let freq = match self.get_number_no_bools(&args[4], cell) {
+                Ok(f) => f.trunc(),
+                Err(_) => {
+                    return CalcResult::new_error(
+                        Error::VALUE,
+                        cell,
+                        "Invalid arguments".to_string(),
+                    )
+                }
+            };
+            *d /= 1.0 + yld / freq;
+        }
+        res
+    }
+
     // This next three functions deal with Treasure Bills or T-Bills for short
     // They are zero-coupon that mature in one year or less.
     //  Definitions:

base/src/functions/mod.rs

@@ -232,6 +232,8 @@ pub enum Function {
     Nominal,
     Nper,
     Npv,
+    Duration,
+    Mduration,
     Pduration,
     Pmt,
     Ppmt,
@@ -313,7 +315,7 @@ pub enum Function {
 }
 
 impl Function {
-    pub fn into_iter() -> IntoIter<Function, 256> {
+    pub fn into_iter() -> IntoIter<Function, 258> {
         [
             Function::And,
             Function::False,
@@ -497,6 +499,8 @@ impl Function {
             Function::Syd,
             Function::Nominal,
             Function::Effect,
+            Function::Duration,
+            Function::Mduration,
             Function::Pduration,
             Function::Tbillyield,
             Function::Tbillprice,
@@ -832,6 +836,8 @@ impl Function {
             "SYD" => Some(Function::Syd),
             "NOMINAL" => Some(Function::Nominal),
             "EFFECT" => Some(Function::Effect),
+            "DURATION" => Some(Function::Duration),
+            "MDURATION" => Some(Function::Mduration),
             "PDURATION" | "_XLFN.PDURATION" => Some(Function::Pduration),
 
             "TBILLYIELD" => Some(Function::Tbillyield),
@@ -1075,6 +1081,8 @@ impl fmt::Display for Function {
             Function::Syd => write!(f, "SYD"),
             Function::Nominal => write!(f, "NOMINAL"),
             Function::Effect => write!(f, "EFFECT"),
+            Function::Duration => write!(f, "DURATION"),
+            Function::Mduration => write!(f, "MDURATION"),
             Function::Pduration => write!(f, "PDURATION"),
             Function::Tbillyield => write!(f, "TBILLYIELD"),
             Function::Tbillprice => write!(f, "TBILLPRICE"),
@@ -1352,6 +1360,8 @@ impl Model {
             Function::Syd => self.fn_syd(args, cell),
             Function::Nominal => self.fn_nominal(args, cell),
             Function::Effect => self.fn_effect(args, cell),
+            Function::Duration => self.fn_duration(args, cell),
+            Function::Mduration => self.fn_mduration(args, cell),
             Function::Pduration => self.fn_pduration(args, cell),
             Function::Tbillyield => self.fn_tbillyield(args, cell),
             Function::Tbillprice => self.fn_tbillprice(args, cell),

base/src/test/mod.rs

@@ -17,6 +17,7 @@ mod test_fn_choose;
 mod test_fn_concatenate;
 mod test_fn_count;
 mod test_fn_day;
+mod test_fn_duration;
 mod test_fn_exact;
 mod test_fn_financial;
 mod test_fn_formulatext;

base/src/test/test_fn_duration.rs

@@ -0,0 +1,350 @@
+#![allow(clippy::unwrap_used)]
+#![allow(clippy::panic)]
+
+use crate::{cell::CellValue, test::util::new_empty_model};
+
+// Test constants for realistic bond scenarios
+const BOND_SETTLEMENT: &str = "=DATE(2020,1,1)";
+const BOND_MATURITY_4Y: &str = "=DATE(2024,1,1)";
+const BOND_MATURITY_INVALID: &str = "=DATE(2016,1,1)"; // Before settlement
+const BOND_MATURITY_SAME: &str = "=DATE(2020,1,1)"; // Same as settlement
+const BOND_MATURITY_1DAY: &str = "=DATE(2020,1,2)"; // Very short term
+
+// Standard investment-grade corporate bond parameters
+const STD_COUPON: f64 = 0.08; // 8% annual coupon rate
+const STD_YIELD: f64 = 0.09; // 9% yield (discount bond scenario)
+const STD_FREQUENCY: i32 = 2; // Semi-annual payments (most common)
+
+// Helper function to reduce test repetition
+fn assert_numerical_result(model: &crate::Model, cell_ref: &str, should_be_positive: bool) {
+    if let Ok(CellValue::Number(v)) = model.get_cell_value_by_ref(cell_ref) {
+        if should_be_positive {
+            assert!(v > 0.0, "Expected positive value at {cell_ref}, got {v}");
+        }
+        // Value is valid - test passes
+    } else {
+        panic!("Expected numerical result at {cell_ref}");
+    }
+}
+
+#[test]
+fn fn_duration_mduration_arguments() {
+    let mut model = new_empty_model();
+
+    // Test argument count validation
+    model._set("A1", "=DURATION()");
+    model._set("A2", "=DURATION(1,2,3,4)");
+    model._set("A3", "=DURATION(1,2,3,4,5,6,7)");
+
+    model._set("B1", "=MDURATION()");
+    model._set("B2", "=MDURATION(1,2,3,4)");
+    model._set("B3", "=MDURATION(1,2,3,4,5,6,7)");
+
+    model.evaluate();
+
+    // Too few or too many arguments should result in errors
+    assert_eq!(model._get_text("A1"), *"#ERROR!");
+    assert_eq!(model._get_text("A2"), *"#ERROR!");
+    assert_eq!(model._get_text("A3"), *"#ERROR!");
+
+    assert_eq!(model._get_text("B1"), *"#ERROR!");
+    assert_eq!(model._get_text("B2"), *"#ERROR!");
+    assert_eq!(model._get_text("B3"), *"#ERROR!");
+}
+
+#[test]
+fn fn_duration_mduration_settlement_maturity_errors() {
+    let mut model = new_empty_model();
+
+    model._set("A1", BOND_SETTLEMENT);
+    model._set("A2", BOND_MATURITY_INVALID); // Before settlement
+    model._set("A3", BOND_MATURITY_SAME); // Same as settlement
+
+    // Both settlement > maturity and settlement = maturity should error
+    model._set(
+        "B1",
+        &format!("=DURATION(A1,A2,{STD_COUPON},{STD_YIELD},{STD_FREQUENCY})"),
+    );
+    model._set(
+        "B2",
+        &format!("=DURATION(A1,A3,{STD_COUPON},{STD_YIELD},{STD_FREQUENCY})"),
+    );
+    model._set(
+        "B3",
+        &format!("=MDURATION(A1,A2,{STD_COUPON},{STD_YIELD},{STD_FREQUENCY})"),
+    );
+    model._set(
+        "B4",
+        &format!("=MDURATION(A1,A3,{STD_COUPON},{STD_YIELD},{STD_FREQUENCY})"),
+    );
+
+    model.evaluate();
+
+    assert_eq!(model._get_text("B1"), *"#NUM!");
+    assert_eq!(model._get_text("B2"), *"#NUM!");
+    assert_eq!(model._get_text("B3"), *"#NUM!");
+    assert_eq!(model._get_text("B4"), *"#NUM!");
+}
+
+#[test]
+fn fn_duration_mduration_negative_values_errors() {
+    let mut model = new_empty_model();
+
+    model._set("A1", BOND_SETTLEMENT);
+    model._set("A2", BOND_MATURITY_4Y);
+
+    // Test negative coupon (coupons must be >= 0)
+    model._set(
+        "B1",
+        &format!("=DURATION(A1,A2,-0.01,{STD_YIELD},{STD_FREQUENCY})"),
+    );
+    model._set(
+        "B2",
+        &format!("=MDURATION(A1,A2,-0.01,{STD_YIELD},{STD_FREQUENCY})"),
+    );
+
+    // Test negative yield (yields must be >= 0)
+    model._set(
+        "C1",
+        &format!("=DURATION(A1,A2,{STD_COUPON},-0.01,{STD_FREQUENCY})"),
+    );
+    model._set(
+        "C2",
+        &format!("=MDURATION(A1,A2,{STD_COUPON},-0.01,{STD_FREQUENCY})"),
+    );
+
+    model.evaluate();
+
+    assert_eq!(model._get_text("B1"), *"#NUM!");
+    assert_eq!(model._get_text("B2"), *"#NUM!");
+    assert_eq!(model._get_text("C1"), *"#NUM!");
+    assert_eq!(model._get_text("C2"), *"#NUM!");
+}
+
+#[test]
+fn fn_duration_mduration_invalid_frequency_errors() {
+    let mut model = new_empty_model();
+
+    model._set("A1", BOND_SETTLEMENT);
+    model._set("A2", BOND_MATURITY_4Y);
+
+    // Only 1, 2, and 4 are valid frequencies (annual, semi-annual, quarterly)
+    let invalid_frequencies = [0, 3, 5, 12]; // Common invalid values
+
+    for (i, &freq) in invalid_frequencies.iter().enumerate() {
+        let row = i + 1;
+        model._set(
+            &format!("B{row}"),
+            &format!("=DURATION(A1,A2,{STD_COUPON},{STD_YIELD},{freq})"),
+        );
+        model._set(
+            &format!("C{row}"),
+            &format!("=MDURATION(A1,A2,{STD_COUPON},{STD_YIELD},{freq})"),
+        );
+    }
+
+    model.evaluate();
+
+    for i in 1..=invalid_frequencies.len() {
+        assert_eq!(model._get_text(&format!("B{i}")), *"#NUM!");
+        assert_eq!(model._get_text(&format!("C{i}")), *"#NUM!");
+    }
+}
+
+#[test]
+fn fn_duration_mduration_frequency_variations() {
+    let mut model = new_empty_model();
+    model._set("A1", BOND_SETTLEMENT);
+    model._set("A2", BOND_MATURITY_4Y);
+
+    // Test all valid frequencies: 1=annual, 2=semi-annual, 4=quarterly
+    let valid_frequencies = [1, 2, 4];
+
+    for (i, &freq) in valid_frequencies.iter().enumerate() {
+        let row = i + 1;
+        model._set(
+            &format!("B{row}"),
+            &format!("=DURATION(A1,A2,{STD_COUPON},{STD_YIELD},{freq})"),
+        );
+        model._set(
+            &format!("C{row}"),
+            &format!("=MDURATION(A1,A2,{STD_COUPON},{STD_YIELD},{freq})"),
+        );
+    }
+
+    model.evaluate();
+
+    // All should return positive numerical values
+    for i in 1..=valid_frequencies.len() {
+        assert_numerical_result(&model, &format!("Sheet1!B{i}"), true);
+        assert_numerical_result(&model, &format!("Sheet1!C{i}"), true);
+    }
+}
+
+#[test]
+fn fn_duration_mduration_basis_variations() {
+    let mut model = new_empty_model();
+    model._set("A1", BOND_SETTLEMENT);
+    model._set("A2", BOND_MATURITY_4Y);
+
+    // Test all valid basis values (day count conventions)
+    // 0=30/360 US, 1=Actual/actual, 2=Actual/360, 3=Actual/365, 4=30/360 European
+    for basis in 0..=4 {
+        let row = basis + 1;
+        model._set(
+            &format!("B{row}"),
+            &format!("=DURATION(A1,A2,{STD_COUPON},{STD_YIELD},{STD_FREQUENCY},{basis})"),
+        );
+        model._set(
+            &format!("C{row}"),
+            &format!("=MDURATION(A1,A2,{STD_COUPON},{STD_YIELD},{STD_FREQUENCY},{basis})"),
+        );
+    }
+
+    // Test default basis (should be 0)
+    model._set(
+        "D1",
+        &format!("=DURATION(A1,A2,{STD_COUPON},{STD_YIELD},{STD_FREQUENCY})"),
+    );
+    model._set(
+        "D2",
+        &format!("=MDURATION(A1,A2,{STD_COUPON},{STD_YIELD},{STD_FREQUENCY})"),
+    );
+
+    model.evaluate();
+
+    // All basis values should work
+    for row in 1..=5 {
+        assert_numerical_result(&model, &format!("Sheet1!B{row}"), true);
+        assert_numerical_result(&model, &format!("Sheet1!C{row}"), true);
+    }
+
+    // Default basis should match basis 0
+    if let (Ok(CellValue::Number(d1)), Ok(CellValue::Number(b1))) = (
+        model.get_cell_value_by_ref("Sheet1!D1"),
+        model.get_cell_value_by_ref("Sheet1!B1"),
+    ) {
+        assert!(
+            (d1 - b1).abs() < 1e-10,
+            "Default basis should match basis 0"
+        );
+    }
+}
+
+#[test]
+fn fn_duration_mduration_edge_cases() {
+    let mut model = new_empty_model();
+
+    model._set("A1", BOND_SETTLEMENT);
+    model._set("A2", BOND_MATURITY_1DAY); // Very short term (1 day)
+    model._set("A3", BOND_MATURITY_4Y); // Standard term
+
+    // Edge case scenarios with explanations
+    let test_cases = [
+        ("B", "A1", "A2", STD_COUPON, STD_YIELD, "short_term"), // 1-day bond
+        ("C", "A1", "A3", 0.0, STD_YIELD, "zero_coupon"),       // Zero coupon bond
+        ("D", "A1", "A3", STD_COUPON, 0.0, "zero_yield"),       // Zero yield
+        ("E", "A1", "A3", 1.0, 0.5, "high_rates"),              // High coupon/yield (100%/50%)
+    ];
+
+    for (col, settlement, maturity, coupon, yield_rate, _scenario) in test_cases {
+        model._set(
+            &format!("{col}1"),
+            &format!("=DURATION({settlement},{maturity},{coupon},{yield_rate},{STD_FREQUENCY})"),
+        );
+        model._set(
+            &format!("{col}2"),
+            &format!("=MDURATION({settlement},{maturity},{coupon},{yield_rate},{STD_FREQUENCY})"),
+        );
+    }
+
+    model.evaluate();
+
+    // All edge cases should return positive values
+    for col in ["B", "C", "D", "E"] {
+        assert_numerical_result(&model, &format!("Sheet1!{col}1"), true);
+        assert_numerical_result(&model, &format!("Sheet1!{col}2"), true);
+    }
+}
+
+#[test]
+fn fn_duration_mduration_relationship() {
+    let mut model = new_empty_model();
+    model._set("A1", BOND_SETTLEMENT);
+    model._set("A2", BOND_MATURITY_4Y);
+
+    // Test mathematical relationship: MDURATION = DURATION / (1 + yield/frequency)
+    model._set(
+        "B1",
+        &format!("=DURATION(A1,A2,{STD_COUPON},{STD_YIELD},{STD_FREQUENCY})"),
+    );
+    model._set(
+        "B2",
+        &format!("=MDURATION(A1,A2,{STD_COUPON},{STD_YIELD},{STD_FREQUENCY})"),
+    );
+    model._set("B3", &format!("=B1/(1+{STD_YIELD}/{STD_FREQUENCY})")); // Manual calculation
+
+    // Test with quarterly frequency and different yield
+    model._set("C1", &format!("=DURATION(A1,A2,{STD_COUPON},0.12,4)"));
+    model._set("C2", &format!("=MDURATION(A1,A2,{STD_COUPON},0.12,4)"));
+    model._set("C3", "=C1/(1+0.12/4)"); // Manual calculation for quarterly
+
+    model.evaluate();
+
+    // MDURATION should equal DURATION / (1 + yield/frequency) for both scenarios
+    if let (Ok(CellValue::Number(md)), Ok(CellValue::Number(manual))) = (
+        model.get_cell_value_by_ref("Sheet1!B2"),
+        model.get_cell_value_by_ref("Sheet1!B3"),
+    ) {
+        assert!(
+            (md - manual).abs() < 1e-10,
+            "MDURATION should equal DURATION/(1+yield/freq)"
+        );
+    }
+
+    if let (Ok(CellValue::Number(md)), Ok(CellValue::Number(manual))) = (
+        model.get_cell_value_by_ref("Sheet1!C2"),
+        model.get_cell_value_by_ref("Sheet1!C3"),
+    ) {
+        assert!(
+            (md - manual).abs() < 1e-10,
+            "MDURATION should equal DURATION/(1+yield/freq) for quarterly"
+        );
+    }
+}
+
+#[test]
+fn fn_duration_mduration_regression() {
+    // Original regression test with known expected values
+    let mut model = new_empty_model();
+    model._set("A1", "=DATE(2016,1,1)");
+    model._set("A2", "=DATE(2020,1,1)");
+    model._set(
+        "B1",
+        &format!("=DURATION(A1,A2,{STD_COUPON},{STD_YIELD},{STD_FREQUENCY})"),
+    );
+    model._set(
+        "B2",
+        &format!("=MDURATION(A1,A2,{STD_COUPON},{STD_YIELD},{STD_FREQUENCY})"),
+    );
+
+    model.evaluate();
+
+    // Verify exact values for regression testing
+    if let Ok(CellValue::Number(v1)) = model.get_cell_value_by_ref("Sheet1!B1") {
+        assert!(
+            (v1 - 3.410746844012284).abs() < 1e-9,
+            "DURATION regression test failed"
+        );
+    } else {
+        panic!("Unexpected value for DURATION");
+    }
+    if let Ok(CellValue::Number(v2)) = model.get_cell_value_by_ref("Sheet1!B2") {
+        assert!(
+            (v2 - 3.263872578002186).abs() < 1e-9,
+            "MDURATION regression test failed"
+        );
+    } else {
+        panic!("Unexpected value for MDURATION");
+    }
+}

base/src/test/test_fn_financial.rs

@@ -1,4 +1,5 @@
 #![allow(clippy::unwrap_used)]
+#![allow(clippy::panic)]
 
 use crate::{cell::CellValue, test::util::new_empty_model};
 

docs/src/functions/financial.md

@@ -28,7 +28,7 @@ You can track the progress in this [GitHub issue](https://github.com/ironcalc/Ir
 | DISC       | <Badge type="info" text="Not implemented yet" /> | –                  |
 | DOLLARDE   | <Badge type="tip" text="Available" />          | –                  |
 | DOLLARFR   | <Badge type="tip" text="Available" />          | –                  |
-| DURATION   | <Badge type="info" text="Not implemented yet" /> | –                  |
+| DURATION   | <Badge type="tip" text="Available" />          | –                  |
 | EFFECT     | <Badge type="tip" text="Available" />          | –                  |
 | FV         | <Badge type="tip" text="Available" />          | [FV](financial/fv) |
 | FVSCHEDULE | <Badge type="info" text="Not implemented yet" /> | –                  |
@@ -36,7 +36,7 @@ You can track the progress in this [GitHub issue](https://github.com/ironcalc/Ir
 | IPMT       | <Badge type="tip" text="Available" />          | –                  |
 | IRR        | <Badge type="tip" text="Available" />          | –                  |
 | ISPMT      | <Badge type="tip" text="Available" />          | –                  |
-| MDURATION  | <Badge type="info" text="Not implemented yet" /> | –                  |
+| MDURATION  | <Badge type="tip" text="Available" />          | –                  |
 | MIRR       | <Badge type="tip" text="Available" />          | –                  |
 | NOMINAL    | <Badge type="tip" text="Available" />          | –                  |
 | NPER       | <Badge type="tip" text="Available" />          | –                  |

docs/src/functions/financial/duration.md

@@ -7,6 +7,5 @@ lang: en-US
 # DURATION
 
 ::: warning
-🚧 This function is not yet available in IronCalc.
+🚧 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).
-[Follow development here](https://github.com/ironcalc/IronCalc/labels/Functions)
 :::

docs/src/functions/financial/mduration.md

@@ -7,6 +7,5 @@ lang: en-US
 # MDURATION
 
 ::: warning
-🚧 This function is not yet available in IronCalc.
+🚧 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).
-[Follow development here](https://github.com/ironcalc/IronCalc/labels/Functions)
 :::