vb6parse 1.0.1

//! # `IPmt` Function
//!
//! Returns a `Double` specifying the interest payment for a given period of an annuity based on periodic, fixed payments and a fixed interest rate.
//!
//! ## Syntax
//!
//! ```vb
//! IPmt(rate, per, nper, pv[, fv[, type]])
//! ```
//!
//! ## Parameters
//!
//! - `rate` (Required): `Double` specifying interest rate per period. For example, if you get a car loan at an annual percentage rate (APR) of 10 percent and make monthly payments, the rate per period is 0.1/12, or 0.0083
//! - `per` (Required): `Double` specifying payment period in the range 1 through nper
//! - `nper` (Required): `Double` specifying total number of payment periods in the annuity. For example, if you make monthly payments on a four-year car loan, your loan has 4 * 12 (or 48) payment periods
//! - `pv` (Required): `Double` specifying present value, or value today, of a series of future payments or receipts. For example, when you borrow money to buy a car, the loan amount is the present value to the lender of the monthly car payments you will make
//! - `fv` (Optional): `Variant` specifying future value or cash balance you want after you've made the final payment. For example, the future value of a loan is $0 because that's its value after the final payment. However, if you want to save $50,000 over 18 years for your child's education, then $50,000 is the future value. If omitted, 0 is assumed
//! - `type` (Optional): `Variant` specifying when payments are due. Use 0 if payments are due at the end of the payment period, or use 1 if payments are due at the beginning of the period. If omitted, 0 is assumed
//!
//! ## Return Value
//!
//! Returns a `Double` representing the interest payment for the specified period:
//! - Negative value indicates money paid out (such as loan interest payments)
//! - Positive value indicates money received (such as investment interest earnings)
//! - The sum of interest payments (`IPmt`) and principal payments (`PPmt`) equals the total payment for a period
//!
//! ## Remarks
//!
//! An annuity is a series of fixed cash payments made over a period of time:
//!
//! - Used to calculate the interest portion of a specific payment
//! - Commonly used for loan amortization calculations
//! - Interest payment decreases over the life of a loan (more principal paid later)
//! - The `per` argument must be in the range 1 through `nper`
//! - `rate` and `nper` must be calculated using payment periods in the same units
//! - For monthly payments, divide annual rate by 12, multiply years by 12
//! - For quarterly payments, divide annual rate by 4, multiply years by 4
//! - All arguments referring to cash paid out are negative; cash received is positive
//! - The interest payment varies by period (unlike fixed total payment)
//! - Use `PPmt` to calculate the principal portion of a payment
//! - Use `Pmt` to calculate the total payment amount
//!
//! ## Typical Uses
//!
//! 1. **Loan Amortization**: Calculate interest portion of loan payments
//! 2. **Mortgage Analysis**: Determine interest paid per payment period
//! 3. **Investment Analysis**: Calculate interest earned per period
//! 4. **Financial Planning**: Project interest expenses over time
//! 5. **Tax Calculations**: Determine deductible interest for tax purposes
//! 6. **Budget Planning**: Forecast interest costs
//! 7. **Refinancing Analysis**: Compare interest costs between loans
//! 8. **Amortization Schedules**: Build payment schedules showing interest breakdown
//!
//! ## Basic Usage Examples
//!
//! ```vb
//! ' Example 1: Calculate first month's interest on a car loan
//! Dim monthlyRate As Double
//! Dim totalMonths As Integer
//! Dim loanAmount As Double
//! Dim interestPayment As Double
//!
//! monthlyRate = 0.08 / 12  ' 8% annual rate
//! totalMonths = 48         ' 4-year loan
//! loanAmount = -20000      ' $20,000 borrowed (negative = cash received)
//!
//! interestPayment = IPmt(monthlyRate, 1, totalMonths, loanAmount)
//! Debug.Print "First month interest: " & Format$(interestPayment, "Currency")
//! ' Prints approximately: -$133.33
//!
//! ' Example 2: Calculate last payment's interest
//! interestPayment = IPmt(monthlyRate, 48, totalMonths, loanAmount)
//! Debug.Print "Last month interest: " & Format$(interestPayment, "Currency")
//! ' Prints approximately: -$3.26 (much less than first month)
//!
//! ' Example 3: Calculate total interest paid in first year
//! Dim totalInterest As Double
//! Dim i As Integer
//! totalInterest = 0
//! For i = 1 To 12
//!     totalInterest = totalInterest + IPmt(monthlyRate, i, totalMonths, loanAmount)
//! Next i
//! Debug.Print "First year interest: " & Format$(totalInterest, "Currency")
//!
//! ' Example 4: Monthly mortgage interest payment
//! Dim mortgageRate As Double
//! Dim mortgageMonths As Integer
//! Dim mortgageAmount As Double
//!
//! mortgageRate = 0.06 / 12  ' 6% annual rate
//! mortgageMonths = 30 * 12  ' 30-year mortgage
//! mortgageAmount = -200000  ' $200,000 loan
//!
//! interestPayment = IPmt(mortgageRate, 1, mortgageMonths, mortgageAmount)
//! Debug.Print "First mortgage payment interest: " & Format$(interestPayment, "Currency")
//! ```
//!
//! ## Common Patterns
//!
//! ```vb
//! ' Pattern 1: Calculate interest for specific payment
//! Function CalculateInterestPayment(loanAmount As Double, annualRate As Double, _
//!                                   years As Integer, paymentNumber As Integer) As Double
//!     Dim monthlyRate As Double
//!     Dim totalPayments As Integer
//!     
//!     monthlyRate = annualRate / 12
//!     totalPayments = years * 12
//!     
//!     CalculateInterestPayment = IPmt(monthlyRate, paymentNumber, totalPayments, -loanAmount)
//! End Function
//!
//! ' Pattern 2: Calculate total interest for a year
//! Function CalculateAnnualInterest(loanAmount As Double, annualRate As Double, _
//!                                  years As Integer, year As Integer) As Double
//!     Dim monthlyRate As Double
//!     Dim totalPayments As Integer
//!     Dim startMonth As Integer
//!     Dim endMonth As Integer
//!     Dim totalInterest As Double
//!     Dim i As Integer
//!     
//!     monthlyRate = annualRate / 12
//!     totalPayments = years * 12
//!     startMonth = (year - 1) * 12 + 1
//!     endMonth = year * 12
//!     
//!     totalInterest = 0
//!     For i = startMonth To endMonth
//!         If i <= totalPayments Then
//!             totalInterest = totalInterest + IPmt(monthlyRate, i, totalPayments, -loanAmount)
//!         End If
//!     Next i
//!     
//!     CalculateAnnualInterest = totalInterest
//! End Function
//!
//! ' Pattern 3: Generate amortization schedule entry
//! Type AmortizationEntry
//!     PaymentNumber As Integer
//!     TotalPayment As Double
//!     InterestPayment As Double
//!     PrincipalPayment As Double
//!     Balance As Double
//! End Type
//!
//! Function GetAmortizationEntry(loanAmount As Double, annualRate As Double, _
//!                               years As Integer, paymentNumber As Integer) As AmortizationEntry
//!     Dim monthlyRate As Double
//!     Dim totalPayments As Integer
//!     Dim entry As AmortizationEntry
//!     
//!     monthlyRate = annualRate / 12
//!     totalPayments = years * 12
//!     
//!     entry.PaymentNumber = paymentNumber
//!     entry.TotalPayment = Pmt(monthlyRate, totalPayments, -loanAmount)
//!     entry.InterestPayment = IPmt(monthlyRate, paymentNumber, totalPayments, -loanAmount)
//!     entry.PrincipalPayment = PPmt(monthlyRate, paymentNumber, totalPayments, -loanAmount)
//!     
//!     GetAmortizationEntry = entry
//! End Function
//!
//! ' Pattern 4: Compare interest costs between loans
//! Function CompareInterestCosts(loan1Amount As Double, loan1Rate As Double, loan1Years As Integer, _
//!                               loan2Amount As Double, loan2Rate As Double, loan2Years As Integer) As String
//!     Dim loan1Interest As Double
//!     Dim loan2Interest As Double
//!     Dim i As Integer
//!     
//!     ' Calculate total interest for loan 1
//!     For i = 1 To loan1Years * 12
//!         loan1Interest = loan1Interest + IPmt(loan1Rate / 12, i, loan1Years * 12, -loan1Amount)
//!     Next i
//!     
//!     ' Calculate total interest for loan 2
//!     For i = 1 To loan2Years * 12
//!         loan2Interest = loan2Interest + IPmt(loan2Rate / 12, i, loan2Years * 12, -loan2Amount)
//!     Next i
//!     
//!     CompareInterestCosts = "Loan 1 total interest: " & Format$(loan1Interest, "Currency") & vbCrLf & _
//!                           "Loan 2 total interest: " & Format$(loan2Interest, "Currency")
//! End Function
//!
//! ' Pattern 5: Calculate deductible interest for tax year
//! Function CalculateTaxDeductibleInterest(loanAmount As Double, annualRate As Double, _
//!                                        totalYears As Integer, taxYear As Integer) As Double
//!     ' Assumes loan started at beginning of year 1
//!     CalculateTaxDeductibleInterest = CalculateAnnualInterest(loanAmount, annualRate, totalYears, taxYear)
//! End Function
//!
//! ' Pattern 6: Determine when interest drops below threshold
//! Function FindPaymentWhenInterestBelow(loanAmount As Double, annualRate As Double, _
//!                                       years As Integer, threshold As Double) As Integer
//!     Dim monthlyRate As Double
//!     Dim totalPayments As Integer
//!     Dim i As Integer
//!     Dim interestPayment As Double
//!     
//!     monthlyRate = annualRate / 12
//!     totalPayments = years * 12
//!     
//!     For i = 1 To totalPayments
//!         interestPayment = Abs(IPmt(monthlyRate, i, totalPayments, -loanAmount))
//!         If interestPayment < threshold Then
//!             FindPaymentWhenInterestBelow = i
//!             Exit Function
//!         End If
//!     Next i
//!     
//!     FindPaymentWhenInterestBelow = -1  ' Never drops below threshold
//! End Function
//!
//! ' Pattern 7: Calculate average monthly interest
//! Function CalculateAverageMonthlyInterest(loanAmount As Double, annualRate As Double, _
//!                                          years As Integer) As Double
//!     Dim totalInterest As Double
//!     Dim totalPayments As Integer
//!     Dim i As Integer
//!     
//!     totalPayments = years * 12
//!     
//!     For i = 1 To totalPayments
//!         totalInterest = totalInterest + IPmt(annualRate / 12, i, totalPayments, -loanAmount)
//!     Next i
//!     
//!     CalculateAverageMonthlyInterest = totalInterest / totalPayments
//! End Function
//!
//! ' Pattern 8: Interest payment with balloon payment
//! Function CalculateInterestWithBalloon(loanAmount As Double, annualRate As Double, _
//!                                       years As Integer, paymentNumber As Integer, _
//!                                       balloonAmount As Double) As Double
//!     Dim monthlyRate As Double
//!     Dim totalPayments As Integer
//!     
//!     monthlyRate = annualRate / 12
//!     totalPayments = years * 12
//!     
//!     CalculateInterestWithBalloon = IPmt(monthlyRate, paymentNumber, totalPayments, _
//!                                         -loanAmount, -balloonAmount)
//! End Function
//!
//! ' Pattern 9: Interest for payment due at beginning
//! Function CalculateInterestPaymentBeginning(loanAmount As Double, annualRate As Double, _
//!                                            years As Integer, paymentNumber As Integer) As Double
//!     Dim monthlyRate As Double
//!     Dim totalPayments As Integer
//!     
//!     monthlyRate = annualRate / 12
//!     totalPayments = years * 12
//!     
//!     ' Type = 1 means payment at beginning of period
//!     CalculateInterestPaymentBeginning = IPmt(monthlyRate, paymentNumber, totalPayments, _
//!                                              -loanAmount, 0, 1)
//! End Function
//!
//! ' Pattern 10: Validate interest payment calculation
//! Function ValidateInterestPayment(loanAmount As Double, annualRate As Double, _
//!                                  years As Integer, paymentNumber As Integer) As Boolean
//!     Dim totalPayment As Double
//!     Dim interestPayment As Double
//!     Dim principalPayment As Double
//!     Dim monthlyRate As Double
//!     Dim totalPayments As Integer
//!     
//!     monthlyRate = annualRate / 12
//!     totalPayments = years * 12
//!     
//!     totalPayment = Pmt(monthlyRate, totalPayments, -loanAmount)
//!     interestPayment = IPmt(monthlyRate, paymentNumber, totalPayments, -loanAmount)
//!     principalPayment = PPmt(monthlyRate, paymentNumber, totalPayments, -loanAmount)
//!     
//!     ' Verify that interest + principal = total payment (within rounding tolerance)
//!     ValidateInterestPayment = (Abs(totalPayment - (interestPayment + principalPayment)) < 0.01)
//! End Function
//! ```
//!
//! ## Advanced Usage Examples
//!
//! ```vb
//! ' Example 1: Complete amortization schedule generator
//! Public Class AmortizationSchedule
//!     Private m_loanAmount As Double
//!     Private m_annualRate As Double
//!     Private m_years As Integer
//!     Private m_schedule As Collection
//!     
//!     Public Sub Initialize(loanAmount As Double, annualRate As Double, years As Integer)
//!         m_loanAmount = loanAmount
//!         m_annualRate = annualRate
//!         m_years = years
//!         GenerateSchedule
//!     End Sub
//!     
//!     Private Sub GenerateSchedule()
//!         Dim monthlyRate As Double
//!         Dim totalPayments As Integer
//!         Dim i As Integer
//!         Dim entry As AmortizationEntry
//!         Dim balance As Double
//!         
//!         Set m_schedule = New Collection
//!         monthlyRate = m_annualRate / 12
//!         totalPayments = m_years * 12
//!         balance = m_loanAmount
//!         
//!         For i = 1 To totalPayments
//!             entry.PaymentNumber = i
//!             entry.TotalPayment = Pmt(monthlyRate, totalPayments, -m_loanAmount)
//!             entry.InterestPayment = IPmt(monthlyRate, i, totalPayments, -m_loanAmount)
//!             entry.PrincipalPayment = PPmt(monthlyRate, i, totalPayments, -m_loanAmount)
//!             balance = balance - entry.PrincipalPayment
//!             entry.Balance = balance
//!             
//!             m_schedule.Add entry
//!         Next i
//!     End Sub
//!     
//!     Public Function GetPayment(paymentNumber As Integer) As AmortizationEntry
//!         If paymentNumber >= 1 And paymentNumber <= m_schedule.Count Then
//!             GetPayment = m_schedule(paymentNumber)
//!         End If
//!     End Function
//!     
//!     Public Function GetTotalInterest() As Double
//!         Dim i As Integer
//!         Dim total As Double
//!         Dim entry As AmortizationEntry
//!         
//!         For i = 1 To m_schedule.Count
//!             entry = m_schedule(i)
//!             total = total + entry.InterestPayment
//!         Next i
//!         
//!         GetTotalInterest = total
//!     End Function
//! End Class
//!
//! ' Example 2: Loan comparison calculator
//! Public Class LoanComparer
//!     Public Function CompareLoanOptions(loanAmount As Double) As String
//!         Dim result As String
//!         Dim option1Interest As Double
//!         Dim option2Interest As Double
//!         Dim option3Interest As Double
//!         Dim i As Integer
//!         
//!         result = "Loan Amount: " & Format$(loanAmount, "Currency") & vbCrLf & vbCrLf
//!         
//!         ' Option 1: 15-year at 5.5%
//!         For i = 1 To 15 * 12
//!             option1Interest = option1Interest + IPmt(0.055 / 12, i, 15 * 12, -loanAmount)
//!         Next i
//!         result = result & "15-year at 5.5%: " & Format$(option1Interest, "Currency") & vbCrLf
//!         
//!         ' Option 2: 20-year at 6.0%
//!         For i = 1 To 20 * 12
//!             option2Interest = option2Interest + IPmt(0.06 / 12, i, 20 * 12, -loanAmount)
//!         Next i
//!         result = result & "20-year at 6.0%: " & Format$(option2Interest, "Currency") & vbCrLf
//!         
//!         ' Option 3: 30-year at 6.5%
//!         For i = 1 To 30 * 12
//!             option3Interest = option3Interest + IPmt(0.065 / 12, i, 30 * 12, -loanAmount)
//!         Next i
//!         result = result & "30-year at 6.5%: " & Format$(option3Interest, "Currency")
//!         
//!         CompareLoanOptions = result
//!     End Function
//! End Class
//!
//! ' Example 3: Interest payment tracker
//! Public Class InterestTracker
//!     Private m_loanAmount As Double
//!     Private m_annualRate As Double
//!     Private m_years As Integer
//!     Private m_currentPayment As Integer
//!     
//!     Public Sub Initialize(loanAmount As Double, annualRate As Double, years As Integer)
//!         m_loanAmount = loanAmount
//!         m_annualRate = annualRate
//!         m_years = years
//!         m_currentPayment = 0
//!     End Sub
//!     
//!     Public Function GetNextInterestPayment() As Double
//!         m_currentPayment = m_currentPayment + 1
//!         If m_currentPayment <= m_years * 12 Then
//!             GetNextInterestPayment = IPmt(m_annualRate / 12, m_currentPayment, _
//!                                          m_years * 12, -m_loanAmount)
//!         Else
//!             GetNextInterestPayment = 0
//!         End If
//!     End Function
//!     
//!     Public Function GetInterestForPayment(paymentNumber As Integer) As Double
//!         If paymentNumber >= 1 And paymentNumber <= m_years * 12 Then
//!             GetInterestForPayment = IPmt(m_annualRate / 12, paymentNumber, _
//!                                         m_years * 12, -m_loanAmount)
//!         Else
//!             GetInterestForPayment = 0
//!         End If
//!     End Function
//!     
//!     Public Function GetYearToDateInterest() As Double
//!         Dim currentYear As Integer
//!         Dim startMonth As Integer
//!         Dim endMonth As Integer
//!         Dim total As Double
//!         Dim i As Integer
//!         
//!         currentYear = Int((m_currentPayment - 1) / 12) + 1
//!         startMonth = (currentYear - 1) * 12 + 1
//!         endMonth = m_currentPayment
//!         
//!         For i = startMonth To endMonth
//!             total = total + IPmt(m_annualRate / 12, i, m_years * 12, -m_loanAmount)
//!         Next i
//!         
//!         GetYearToDateInterest = total
//!     End Function
//! End Class
//!
//! ' Example 4: Refinancing analyzer
//! Function AnalyzeRefinancing(currentLoanBalance As Double, currentRate As Double, _
//!                            remainingYears As Integer, newRate As Double, _
//!                            newYears As Integer, closingCosts As Double) As String
//!     Dim currentTotalInterest As Double
//!     Dim newTotalInterest As Double
//!     Dim i As Integer
//!     Dim result As String
//!     
//!     ' Calculate remaining interest on current loan
//!     For i = 1 To remainingYears * 12
//!         currentTotalInterest = currentTotalInterest + _
//!             IPmt(currentRate / 12, i, remainingYears * 12, -currentLoanBalance)
//!     Next i
//!     
//!     ' Calculate total interest on new loan
//!     For i = 1 To newYears * 12
//!         newTotalInterest = newTotalInterest + _
//!             IPmt(newRate / 12, i, newYears * 12, -currentLoanBalance)
//!     Next i
//!     
//!     result = "Current loan interest: " & Format$(currentTotalInterest, "Currency") & vbCrLf
//!     result = result & "New loan interest: " & Format$(newTotalInterest, "Currency") & vbCrLf
//!     result = result & "Closing costs: " & Format$(closingCosts, "Currency") & vbCrLf
//!     result = result & "Net savings: " & _
//!              Format$(currentTotalInterest - newTotalInterest - closingCosts, "Currency")
//!     
//!     AnalyzeRefinancing = result
//! End Function
//! ```
//!
//! ## Error Handling
//!
//! The `IPmt` function can raise errors:
//!
//! - **Invalid procedure call (Error 5)**: If `per` is less than 1 or greater than `nper`
//! - **Type Mismatch (Error 13)**: If arguments are not numeric
//! - **Overflow (Error 6)**: If result exceeds Double range
//!
//! ```vb
//! On Error GoTo ErrorHandler
//! Dim interestPayment As Double
//!
//! interestPayment = IPmt(0.08 / 12, 1, 48, -20000)
//! Debug.Print "Interest payment: " & Format$(interestPayment, "Currency")
//! Exit Sub
//!
//! ErrorHandler:
//!     MsgBox "Error calculating interest: " & Err.Description, vbCritical
//! ```
//!
//! ## Performance Considerations
//!
//! - **Calculation Intensity**: `IPmt` involves complex financial calculations
//! - **Loop Performance**: Calculating all payments can be slow for long-term loans
//! - **Caching**: Consider caching amortization schedules rather than recalculating
//! - **Precision**: Uses `Double` precision for accurate financial calculations
//!
//! ## Best Practices
//!
//! 1. **Consistent Periods**: Ensure rate and nper use same time units (monthly, quarterly, etc.)
//! 2. **Sign Convention**: Use negative for cash paid, positive for cash received
//! 3. **Validate Period**: Check that `per` is between 1 and `nper`
//! 4. **Error Handling**: Wrap financial calculations in error handlers
//! 5. **Rounding**: Round currency values appropriately for display
//! 6. **Documentation**: Document assumptions about payment timing (beginning/end of period)
//! 7. **Testing**: Verify that `IPmt` + `PPmt` = `Pmt` for each period
//!
//! ## Platform and Version Notes
//!
//! - Available in all VB6 versions
//! - Part of VBA financial functions
//! - Uses `Double` precision (not Currency type)
//! - Consistent with Excel's `IPMT` function
//! - Sign convention follows financial standards
//!
//! ## Limitations
//!
//! - Does not handle variable interest rates
//! - Assumes constant payment amounts
//! - Does not account for fees or other charges
//! - Limited to fixed annuity calculations
//! - No built-in support for skip payments or extra payments
//!
//! ## Related Functions
//!
//! - `PPmt`: Principal payment for a period
//! - `Pmt`: Total payment for a period
//! - `Rate`: Interest rate per period
//! - `NPer`: Number of periods
//! - `PV`: Present value
//! - `FV`: Future value

#[cfg(test)]
mod tests {
    use crate::*;

    #[test]
    fn ipmt_basic() {
        let source = r"
Sub Test()
    interest = IPmt(0.08 / 12, 1, 48, -20000)
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_with_future_value() {
        let source = r"
Sub Test()
    interest = IPmt(rate, period, nper, pv, fv)
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_with_type() {
        let source = r"
Sub Test()
    interest = IPmt(monthlyRate, 1, totalMonths, loanAmount, 0, 1)
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_in_loop() {
        let source = r"
Sub Test()
    Dim i As Integer
    For i = 1 To 12
        totalInterest = totalInterest + IPmt(monthlyRate, i, totalMonths, loanAmount)
    Next i
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_if_statement() {
        let source = r#"
Sub Test()
    If IPmt(rate, period, nper, pv) < threshold Then
        MsgBox "Interest below threshold"
    End If
End Sub
"#;
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_function_return() {
        let source = r"
Function CalculateInterest() As Double
    CalculateInterest = IPmt(0.06 / 12, 1, 360, -200000)
End Function
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_abs() {
        let source = r"
Sub Test()
    positiveInterest = Abs(IPmt(rate, period, nper, pv))
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_format() {
        let source = r#"
Sub Test()
    formatted = Format$(IPmt(rate, period, nper, pv), "Currency")
End Sub
"#;
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_debug_print() {
        let source = r#"
Sub Test()
    Debug.Print "Interest: " & IPmt(monthlyRate, 1, totalMonths, loanAmount)
End Sub
"#;
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_array_assignment() {
        let source = r"
Sub Test()
    interestPayments(i) = IPmt(rate, i, nper, pv)
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_property_assignment() {
        let source = r"
Sub Test()
    loan.InterestPayment = IPmt(loan.Rate, loan.Period, loan.NPer, loan.Amount)
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_in_class() {
        let source = r"
Private Sub Class_Initialize()
    m_interest = IPmt(m_rate, m_period, m_nper, m_pv)
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_with_statement() {
        let source = r"
Sub Test()
    With loanInfo
        .Interest = IPmt(.Rate, .Period, .NPer, .PV)
    End With
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_function_argument() {
        let source = r"
Sub Test()
    Call ProcessPayment(IPmt(rate, period, nper, pv))
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_comparison() {
        let source = r#"
Sub Test()
    If IPmt(rate1, period, nper, pv) > IPmt(rate2, period, nper, pv) Then
        MsgBox "First loan has higher interest"
    End If
End Sub
"#;
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_select_case() {
        let source = r#"
Sub Test()
    Select Case IPmt(rate, period, nper, pv)
        Case Is < -100
            MsgBox "High interest"
        Case Is < -50
            MsgBox "Medium interest"
    End Select
End Sub
"#;
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_msgbox() {
        let source = r#"
Sub Test()
    MsgBox "Interest payment: " & Format$(IPmt(rate, period, nper, pv), "Currency")
End Sub
"#;
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_collection_add() {
        let source = r"
Sub Test()
    payments.Add IPmt(rate, i, nper, pv)
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_math_expression() {
        let source = r"
Sub Test()
    totalPayment = IPmt(rate, period, nper, pv) + PPmt(rate, period, nper, pv)
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_iif() {
        let source = r#"
Sub Test()
    result = IIf(IPmt(rate, period, nper, pv) < 0, "Payment", "Receipt")
End Sub
"#;
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_nested_calculation() {
        let source = r"
Sub Test()
    yearlyInterest = IPmt(annualRate / 12, month, years * 12, -loanAmount) * 12
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_do_loop() {
        let source = r"
Sub Test()
    Dim period As Integer
    period = 1
    Do While period <= nper
        total = total + IPmt(rate, period, nper, pv)
        period = period + 1
    Loop
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_boolean_expression() {
        let source = r"
Sub Test()
    isHighInterest = Abs(IPmt(rate, 1, nper, pv)) > threshold And period = 1
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_type_assignment() {
        let source = r"
Sub Test()
    Dim entry As AmortizationEntry
    entry.InterestPayment = IPmt(monthlyRate, paymentNum, totalMonths, loanAmount)
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_range_check() {
        let source = r"
Sub Test()
    If period >= 1 And period <= nper Then
        interest = IPmt(rate, period, nper, pv)
    End If
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_parentheses() {
        let source = r"
Sub Test()
    value = (IPmt(rate, period, nper, pv))
End Sub
";
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }

    #[test]
    fn ipmt_concatenation() {
        let source = r#"
Sub Test()
    result = "Interest: " & IPmt(rate, period, nper, pv)
End Sub
"#;
        let (cst_opt, _failures) = ConcreteSyntaxTree::from_text("test.bas", source).unpack();
        let cst = cst_opt.expect("CST should be parsed");

        let tree = cst.to_serializable();

        let mut settings = insta::Settings::clone_current();
        settings
            .set_snapshot_path("../../../../../snapshots/syntax/library/functions/financial/ipmt");
        settings.set_prepend_module_to_snapshot(false);
        let _guard = settings.bind_to_scope();
        insta::assert_yaml_snapshot!(tree);
    }
}