Max.qvs

// Max() function for load script
// Input: variable to store return value, two numeric values
// Output: the larger of the two input values

Sub MaxExceptionDisplayDebugInfo
    Trace Error encountered while attempting to determine the maximum of values:;
    Trace Value A = $(vValueA);
    Trace Value B = $(vValueB);
    Call ThrowException('Error encountered while calling Max() subroutine.');
End Sub;

Sub MaxExceptionNotANumber(vValueA, vValueB)
    Trace Non-numeric value detected when calling Max() subroutine.;
    Call MaxExceptionDisplayDebugInfo
End Sub;

Sub MaxExceptionUnknownError(vValueA, vValueB)
    Call MaxExceptionDisplayDebugInfo
End Sub;

Sub Max(vMax, vValueA, vValueB)
    [Values]:
    Load
        *,
        If(
            [Value Is A Number],
            0,
            1
        ) AS [Non-Numeric Value Count]
    ;
    
    Load
        *,
        IsNum([Value]) AS [Value Is A Number]
    Inline [
        Value
        $(vValueA)
        $(vValueB)
    ]
    ;
    
    [Non-Numeric Value Count]:
    Load
        Sum([Non-Numeric Value Count]) AS [Non-Numeric Value Count]
    Resident [Values]
    ;
    
    Drop Table [Values];
    Let vNonNumericValueCount = Peek('Non-Numeric Value Count', 0, 'Non-Numeric Value Count');
    Drop Table [Non-Numeric Value Count];
    
    If $(vNonNumericValueCount) > 0 Then
        Call MaxExceptionNotANumber(vValueA, vValueB)
    End If
    
    If $(vValueA) > $(vValueB) Then
        vMax = $(vValueA)
    ElseIf $(vValueB) > $(vValueA) Then
        vMax = $(vValueB)
    ElseIf $(vValueA) = $(vValueB) Then
        vMax = $(vValueA)
    Else
        Call MaxExceptionUnknownError(vValueA, vValueB)
    End If
End Sub;