LdBeth's Mail Language

Revision History
0.1.1 2023-1-22

Improve quotation elements.

1 Introduction

I was inspired by Org MIME to compose HTML email in Emacs but I don't use Org. Personally I think XML is all the way better with XSLT and RelaxNG. How about text/enriched? Well it is almost dead.

I'm not afraid of writing HTML directly, but I want to make the result as modern as possible, so a lot of formatting stuff of HTML has been moved to CSS, and in modern time HTML email makes a lot use of inline CSS. Meanwhile, I'm using Emacs' shr library to render my HTML emails most of the time, so I also want the result to be recognizable in Emacs.

MJML is something similar to what I want, but:

  1. It is commercial email oriented. I just want to write personalized mail.

  2. The result requires lot of modern browser features not available in Emacs.

  3. I don't want to install npm.

So a simple conclusion: I want something that can be easily converted to HTML5 with XSLT 1.0 only, since I don't have Saxon installed on my local computer. Also I need a RelaxNG Schema so I can editing the format with Emacs.

2 Sample files

This is the sample XML source file for version 0.1. The corresponding HTML output.

3 Structure of LsML

✎︎
Note

When in doubt, reference the sample input file.

3.1 Document Root

The root element is lsml, it has XML name space https://ldbeth.sdf.org/lsml.

The version attribute is mandatory and currently the only permitted value is 0.1. The format attribute can have htmlonly or usetext as value, and is used to control MUA.

There are two required elements: head, body. Other elements which are optional: sig, which is used to format signature; headers and mime are use to provide information to MUA, and are for internal use only.

3.2 Header

3.2.1 Common Email headers

Subject, From, To, Cc, Bcc are common email headers, and they are in capitalized form because XSLT 1.0 has no easy capitalize string solution.

For elements that are supposed to take email address lists as values, the format is:

  |(<name>person name</name><email>email address</email>)+

3.2.2 Additional headers

Additional headers can be added as children of headers element. Notice that field name is case sensitive.

  |(<field>content</field>)*

3.2.3 Preview

The idea is from MJML, preview adds a paragraph of hidden text in the body so it can only viewed from email summary.

3.3 Body

The vertical mode elements are: p (paragraph), l (list), hr (horizontal rule), img (inline image), section, raw (raw HTML), code (code block), quote (quote message).

3.3.1 Inline elements

They are: b, i, tt, ins, del, kbd, c, url, br. Where c stands for cite, the other are functioning similar to standard HTML tags. However, they may not necessary be translated to exactly the same tags during processing. The raw tag can also be used to create inline HTML.

3.3.2 Section

This is similar to section tag from DocBook, that it can be arbitrarily nested.

Each section must have a title element. The title can have optional level attribute corresponding to h1 to h6 titles in HTML.

3.3.3 Quotation

Use quote email messages, there are three optional attributes:

date

RFC822 timestamp.

from

Author of original message.

cite

URL to original message.

To make quoting HTML emails much easier, this elements also accepts elements from XHTML namespace.

There is also vcode, for verbatim inclusion of original message.

3.3.4 Code block

The code element can be used to format code block. The optional lang attribute specifies programming language used.