In this question here on the TeX-forum, I asked for a method to store variables in a convenient way, so that non-techies are not scared off to work with LaTeX. To bring this up to a new level, I'd like to define the complete structure of the document, in this case an invoice, in the .cls file, including text output.

This is not really possible, as you are not allowed to print content before the begin{document} command.

What I'd like to have is a two documents folder setup. The invoice.clsdocument class file, preformatting everything and the main.tex file in which the end user can enter the variables as shown in the previous question and set up the bill.

For the bill I defined a newenvironment with some custom commands and counters, so that the total amount is calculated by LaTeX and printed on the page.

Ideally the main.tex should only contain these two things:

documentclass{invoice}



begin{document}



    StoreInvoiceData{%

        %% %%%%%%

        %% Sender

        %% %%%%%%

        Tagline     =   {Hello World},

        FirstName   =   {Victor K.},

        LastName    =   {Driscoll},

        Street      =   {1616 Hill Croft Farm Road},

        Zip         =   {95932},

        Town        =   {Colusa},

        Country     =   {USA},

        IBAN        =   {YY24KIHB12476423125915947930915268},

        SWIFT       =   {ANTSUB4L},



        %% %%%%%%%%

        %% Receiver

        %% %%%%%%%%

        ClientFirstName     =   {John},

        ClientLastName      =   {Doe},

        ClientStreet        =   {123 Main St},

        ClientZip           =   {43221},

        ClientTown          =   {Anytown},

        ClientCountry       =   {USA}

    }



    begin{invoicetable}

        %% %%%%%%%

        %% Hosting

        %% %%%%%%%

        feetype{Hosting Expenses}

        unitrow{Test 1}{1}{10}    % unitrow{Name}{Quantity}{Item price}

        unitrow{Test 2}{1}{15}

        unitrow{Test 3}{1}{20}

        subtotal



        %% %%%%%%%%%%%%

        %% Maintainance

        %% %%%%%%%%%%%%

        feetype{Maintenance Fees}

        unitrow{Test 4}{2}{15}

        unitrow{Test 5}{1}{20}

        unitrow{Test 6}{5}{25}

        unitrow{Test 7}{1}{30}

        subtotal

    end{invoicetable}



end{document}

The invoice.cls should handle all the rest. If no values are entered in the StoreInvoiceData-list, blank fields should be printed. The class should automatically print the header (a TikZ rectangle with nodes that include the name an the tagline), the address field (also a TikZ rectangle placed at the correct coordinates to match the window in an envelope) and so on.

At the moment this is all done by newcommands which are then called in the main.tex, but as I said, I want tho keep that file as clean as possible and I'm sure that there is a possibility to define the complete layout in a LaTeX class.

If something is not clear, please feel free to ask.

Thanks for your help, I really appreciate it!

Here's a sample of a standard US commercial invoice class which I hacked up a while ago. It defines some user commands for the invoice document, and takes the values for the invoice itself from a CSV file. The class itself formats everything, and the user document is very simple.

There are various ways in which this could be made better, but it should give you enough of a start to see how this kind of thing can be done.

Update (January 2019)

I've now packaged this as a document class, with support for multipage invoices, return address config files and documentation. It's available on CTAN and included in TeX Live and MikTeX.

invoice-class

% US Commericial Invoice Class

% Copyright 2008-2017 by Alan Munn amunn@msu.edu

%

% This class may be distributed and/or modified under the

% conditions of the LaTeX Project Public License, either version 1.3

% of this license or any later version.

% The latest version of this license is in

%   http://www.latex-project.org/lppl.txt

% and version 1.3 or later is part of all distributions of LaTeX

% version 2005/12/01 or later.

%

% This package has the LPPL maintenance status `maintained'.

% 

% The Current Maintainer of this package is Alan Munn amunn@msu.edu

%

definvc@date{2008/07/15}

definvc@version{1.0}

NeedsTeXFormat{LaTeX2e}

ProvidesClass{invoice-class}[invc@datespace  Commercial Invoice invc@version]

LoadClass[11pt]{article}

RequirePackage[margin=1in]{geometry}

RequirePackage{datatool}

RequirePackage{multicol}

RequirePackage{array}

RequirePackage{tabularx}

RequirePackage{dcolumn}

RequirePackage{fancyhdr}

renewcommand{rmdefault}{sfdefault}

newcommand*{invc@BL}[1]{rule{#1}{.5pt}}

newcommand*invc@NL{tabularnewline}

newcolumntype{d}{D{.}{.}{6.2}}

newcommand*{invc@mc}{multicolumn{1}{c|}}

newcommand*{invc@waybill}{

fbox{textbf{Waybill Number:} invc@waybillnum}}

newcommand*{waybill}[1]{gdefinvc@waybillnum{#1}}

newcommand{toaddress}[1]{gdefinvc@toaddress{#1}}

newcommand*{destination}[1]{gdefinvc@destination{#1}}

newcommand*{carrier}[1]{gdefinvc@carrier{#1}}

newcommand*{InputFile}[1]{gdefinvc@inputfile{#1}}

newcommand*{weight}[2]{gdefinvc@pounds{#1}gdefinvc@oz{#2}}

newcommand*{packages}[1]{gdefinvc@packages{#1}}

letinvc@shippingdatetoday

% These could be made into user commands but if they are fixed, they can simply be

% hard coded as is done here

newcommand{invc@fromaddress}{%

The Duck Company\

Some Avenue\

Somewhere MI 48823\

USA\

Tel. 555-555-5555\

}

newcommand*{invc@shipper}{Prof. van Duck}

newcommand*{invc@location}{Somewhere, MI}

%

pagestyle{fancy}

parindent=0pt

lhead{}

chead{Large sffamily bfseries Commercial Invoice }

rhead{}

lfoot{}

cfoot{sffamilythepage}

rfoot{}

renewcommand{headrulewidth}{0.4pt}

renewcommand{footrulewidth}{0pt}

thispagestyle{fancy}

sffamily

newcommand{printinvoice}{%

invc@waybill

begin{multicols}{2}



{Largebfseries From:}



invc@fromaddress



columnbreak



{Largebfseries To:}



invc@toaddress

end{multicols}



setlength{extrarowheight}{9pt}

begin{tabularx}{linewidth}{|*{4}{>{centering}X|}}

hline

textbf{scriptsize Country of ultimate destination:} & textbf{scriptsize Exporting Carrier} & textbf{scriptsize Total number of packages} & textbf{scriptsize Gross Weight} invc@NL

invc@destination & invc@carrier &

invc@packages & invc@pounds~lb invc@oz~oz invc@NL

hline

end{tabularx}

%

DTLloaddb{invoice}{invc@inputfile}

DTLsumcolumn{invoice}{Amount}{invc@total}

setlength{extrarowheight}{3pt}

begin{tabularx}{linewidth}{|X|p{1in}|p{.75in}|d|d|}

hline

centeringbfseries Description & centeringbfseries Country of Origin & centering bfseries Quantity &invc@mc{bfseries Unit Value$} & invc@mc{bfseries Amount (USD)}invc@NL

hline

DTLforeach{invoice}{%

description=Description,country=Country,quantity=Quantity,unitvalue=UnitValue,amount=Amount}{%

description & country & quantity & unitvalue & amount\} & & & & \hline

multicolumn{4}{|r|}{bfseries Currency type and amount}& DTLdecimaltocurrency{invc@total}{invc@subtotal}invc@subtotal   invc@NL

multicolumn{4}{|r|}{bfseries Packing cost} & invc@NL

multicolumn{4}{|r|}{bfseries Shipping cost} & invc@NL

multicolumn{4}{|r|}{bfseries Insurance cost} & invc@NL

hlinehline

multicolumn{4}{|r|}{bfseries Total Invoice Value} & DTLdecimaltocurrency{invc@total}{invc@grandtotal}invc@grandtotal invc@NL

hline

end{tabularx}

vskip 5ex

{Largebfseries Notes:}



{footnotesize These commodities, technologies, or software were exported from the United States of

America in accordance with the Export Administration regulations. Diversion contrary to

U.S. law is prohibited.



It is hereby certified that this invoice shows: (1) the actual price of the goods described,

(2) that no other invoice has been or will be issued, and (3) that all particulars are true

and correct.}



setlength{extrarowheight}{18pt}

begin{tabular}{|p{3in}|p{1.75in}|}

hline

textbf{scriptsize Name:} hskip 2em invc@shipper & textbf{scriptsize Date:} invc@shippingdate invc@NL



hline

multicolumn{2}{|l|}{textbf{scriptsize Location:} hskip 1em invc@location}invc@NL

hline

multicolumn{2}{|l|}{ textbf{scriptsize Signature:}}invc@NL

hline

end{tabular}

}

endinput

Sample user document

This is a sample user document. I've included the CSV file using filecontents but it would normally be an external file.

documentclass{invoice-class}

usepackage{filecontents}

begin{filecontents*}{jobname.csv}

Description, Country, Quantity, UnitValue, Amount

Yellow Ducks, USA, 5, 2.00, 10.00

Pink Ducks, USA, 4, 15.00, 60.00

Blue Ducks, USA, 6, 5.00, 30.00

Orange Ducks, USA, 1, 4.00, 4.00

Red Ducks, USA, 30, 2.00, 60.00

end{filecontents*}

InputFile{jobname.csv}

waybill{8273205776}

carrier{FedEx}

destination{Brazil}

toaddress{Paulo Cereda\Rua Bonita\Cidade de Patos\SP\Brazil}

weight{1}{1}

packages{1}

begin{document}

printinvoice

end{document}

Output