AsciiDoc Invoice with Calculations

AsciiDoc-based invoice template with automatic calculations via a Ruby extension.

Files

• invoice.adoc — Invoice template with parameterized fields
• calc-extension.rb — Ruby extension that evaluates {calc:...} expressions
• invoice-sample.pdf — Original template (for reference)

Usage

Requires Asciidoctor (Ruby-based).

# Generate HTML
asciidoctor -r ./calc-extension.rb invoice.adoc

# Generate PDF (requires asciidoctor-pdf gem)
asciidoctor-pdf -r ./calc-extension.rb invoice.adoc

How It Works

All invoice data is defined as AsciiDoc attributes at the top of invoice.adoc. The calc-extension.rb processes {calc:expression} patterns and replaces them with computed values formatted in German locale (e.g. 12.426,00):

:price: 114.00
:qty: 109
:total: {calc:{qty}*{price}}   → 12.426,00

Invoice Fields

Attribute	Description
Company / Customer	Name, address, contact, bank details
invoice_number	Invoice number
invoice_date	Invoice date
due_date	Payment due date
description	Free-text field (e.g. service period, project name)
item<N>_desc	Line item description
item<N>_details	Line item details (free-text, e.g. order/article numbers)
item<N>_qty	Quantity
item<N>_price	Unit price
item<N>_total	Line total (use {calc:...})
subtotal, vat_amount, total	Calculated totals