Monetary / financial calculations inside your QRF → BOQ automation

1. Exact decimal precision (no binary-float rounding surprises).
2. Convenience helpers for currency formatting, FX, amortisation, etc.

1. Core precision → decimal

   from decimal import Decimal, ROUND_HALF_UP
   
   qty   = Decimal('12.50')     # kg
   rate  = Decimal('78.35')     # $/kg
   total = (qty * rate).quantize(Decimal('0.01'), ROUND_HALF_UP)

2. Money wrapper → money or py-moneyed

   from money import Money
   
   unit_price = Money('78.35', 'USD')
   line_total = Money('12.50', 'USD') * unit_price

3. Excel / reporting → openpyxl, xlsxwriter (they both preserve Decimal precision when you write values).
4. Optional extras
   • forex-python – real-time FX rates for multi-currency bids.
   • numpy-financial – NPV, IRR, loan amortisation if you need financing tables.
   • babel – locale-aware currency formatting.

from decimal import Decimal
from openpyxl import Workbook
from money import Money

wb = Workbook()
ws = wb.active
ws.append(['Item', 'Qty (kg)', 'Rate ($)', 'Amount ($)'])

for item, qty, rate in [
        ('Column UC203', Decimal('253.4'), Decimal('1.08')),
        ('Beam UB305', Decimal('417.9'), Decimal('1.08'))]:
    amount = Money(qty * rate, 'USD')
    ws.append([item, float(qty), float(rate), str(amount)])

wb.save('BOQ_financial.xlsx')