Copyright (c) 2006, Chris Parsons (chris@edendevelopment.co.uk)
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INVOICE DSL
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*Summary*

This invoice DSL allows you to write invoices using a simple Ruby-like syntax 
and then process them using various filters to get the output that you need.

I wrote it for fun, to learn about DSLs in Ruby, and also for a quick way to
 do my invoice calculations. 

*Development*

The code is GPL'd, so feel free to modify it, but I'd appreciate a patch so 
that I can merge any bugfixes or enhancements back into the trunk and benefit 
everyone. If you wish to submit a patch, please install rspec and make
sure that 'spec invoice_spec.rb' passes before you submit. Send patches to
info@edendevelopment.co.uk.

*Installation*

$ svn co http://svn.edendevelopment.co.uk/public/invoice_dsl

This will install the code into your current directory. Simple, huh? :-)

*Quick Start*

1. First write your invoice and save it as 'myinvoice.rb'. You can use 
'example_invoices.rb' for reference.

2. Run the following command:

	./process_invoice.rb myinvoice.rb invoice_template.tex
	
This will save out a number of invoices into 'tex' files, with filenames 
corresponding to the 'codes' you have given the invoice in step 1. For 
example, the example_invoices.rb file generates the following files when run 
as above:

	2006-45.tex
	2006-46.tex
	
As an added bonus, the process_invoice script will invoke 'pdflatex' for you
to generate pdfs for each of these files, if you have it.

Check out 2006-45.pdf for the final example output.

*Writing new templates*

The LaTeX template is the main one, but I've included a quick YAML template 
also - this simply produces a YAML file for each invoice, which can then be
processed futher.

The template use ERB for expansion, so pretty much any ERB template will do 
the trick. Use the 'invoice_template.tex' as an example. It should be trivial 
to add invoice templates for HTML, plus other formats; if you produce any let
me know!

*Tip*

Create a pdf and save it as 'background.pdf' in the same directory as the
script, and the LaTeX template will use it as the background of the PDF it 
generates. I use this for my letterhead on invoices I don't intend to print
but send electronically.