GELLMU

A Bridge from LaTeX to XML

William F. Hammond

University at Albany
Albany, New York (USA)
`http://www.albany.edu/~hammond`
CTAN: support/gellmu

TUG 2001, August, 2001

1. Single Source Authoring

Situation Wanted

Write a single source file to produce:

Finely Typeset Print
Consistent, Valid HTML

and to benefit from:

No Need for Intervention Beyond Source
The Possibility of Other Translations

2. Translating LaTeX

Almost Impossible
Good Structure a Help
May Require Human Intervention
Need to Proof Read Twice

3. Translating HTML

Reliable
But:
1. No Math in HTML
2. HTML Generally Less Rich Than LaTeX
3. Nuisances: # $ % & ~ _ ^ \ { } < >

4. Pie in the Sky

A Dialect of classical LaTeX that is

Translatable
Rich
Agreed Upon

5. XML

eXtensible Markup Language

Data Under a Template for Translation
Originated by

World Wide Web Consortium (W3C)
Sun Microsystems
Universal Exchange

6. XML

Many Templates
Synonym for XML Template:

Document Type
Two worlds
1. Classical Documents:
  Examples: HTML, Docbook, TEI, ...
2. Electronic Data Interchange (EDI)
  Example: Graham William's TeX Catalogue found on CTAN
  help/Catalogue/catalogue.html

7. GELLMU

Generalized Extensible LaTeX-Like MarkUp

A markup interface for writing (SGML or) XML.
LaTeX-like notation more succinct than that of XML.
Extensible using GELLMU's \newcommand with arguments. (SGML has no analogue of macros with arguments.)
Other metacommand facilities including:
(1) \documenttype (2) \macro

8. Modes

Basic
Advanced
1. Regular
2. Other (less fully developed)

9. Basic GELLMU for XHTML

Source	Derived XML	Presentation
`\em{bird}`	`<em>bird</em>`	bird
`\b{cat}`	`<b>cat</b>`	cat
`\kbd{dog}`	`<kbd>dog</kbd>`	`dog`
`\hr;`	`<hr />`	(horizontal rule)

10. The Syntatic Translator

source markup -----> XML or SGML

`\foo{ ... }`	-->	`<foo> . . . </foo>`
`\foo;`	-->	`<foo/>`
`\foo`	-->	`<foo>`
`\foo:`	-->	`</foo>`
`\foo[a="x" ...]`	-->	`<foo a="x" ...>`

11. Syntactic Differences from LaTeX

Command names (element names) may contain numbers.
Example: \frac23 is a command name.
Arguments must be delimited with braces or brackets.
No white space between command name and first argument delimiter.
No white space between delimiters of successive arguments.
Bracketed arguments may not be optional.

12. Syntax in Basic Mode

Miscellaneous Rules

Brackets are only for attribute specifications.

Unescaped loose braces are insignificant.

Escaping in Basic Mode

Special character	`%`	`\`	`{`	`}`	`#`
Escaped form	`\%`	`\\`	`\{`	`\}`	`\#`

13. Basic GELLMU for XHTML

Anchors

Write:

the WWW \a[href="http://www.w3.org/"

]{Consortium} site

for generating the XML:

the WWW <a href="http://www.w3.org/"

>Consortium</a> site

to produce:

the WWW Consortium site

14. \newcommand with XHTML

Definitions

\newcommand{\emph}[1]{\em{#1}}

\newcommand{\w3ref}[2][]{%

\a[href="http://www.w3.org/#1"]{#2}}

Invocations

Using GELLMU's \emph{newcommand}

one can reduce the markup required

for an anchor to \w3ref{W3C}'s

\w3ref{Math/}{MathML} site.

Rendering: Using GELLMU's newcommand one can reduce the markup required for an anchor to W3C's MathML site.

15. A CTAN Catalogue Entry

\begin{entry}[

id="gellmu"

datestamp="2001/07/30"

modifier="hammond@math.albany.edu"

]

\begin{about}

\name{gellmu}

\caption{LaTeX-like markup for

writing XML documents}

\author{\name{William F. Hammond}

\email{hammond@math.albany.edu}}

\license[type="gpl"];

\version{\number{0.7.4}

\released{2001/07/26}}

\end{about}

\begin{description}

\begin{abstract}

. . .

\end{abstract}

\end{description}

\distribution{

\ctan{support/gellmu}

}

\end{entry}

16. CTAN Catalogue XML

<entry

id="gellmu"

datestamp="2001/07/30"

modifier="hammond@math.albany.edu"

>

<about>

<name>gellmu</name>

<caption>LaTeX-like markup for

writing XML documents</caption>

<author><name>William F. Hammond</name>

<email>hammond@math.albany.edu</email></author>

<license type="gpl"/>

<version><number>0.7.4</number>

<released>2001/07/26</released></version>

</about>

<description>

<abstract>

. . .

</abstract>

</description>

<distribution>

<ctan>support/gellmu</ctan>

</distribution>

</entry>

17. Advanced GELLMU

Multiple Argument/Option Syntax
Example instance: \frac{2}{3} for {2}/{3} if the name frac is provided as an element with two required sub-elements in the document type.
Various Short Reference Features
Example: The use of blank lines, as appropriate in context, for new paragraphs if provided.
Concept of advanced GELLMU is not fully developed.
Main Instance: Regular GELLMU, represented by GELLMU's own didactic article document type.

18. Why is article ``Didactic''?

Intended as a first XML document type for LaTeX authors
Sits in the middle between
1. What LaTeX authors are accustomed to.
2. What high end XML people think is needed.
Room to adjust and expand.

19. Advanced GELLMU for article

Source	Derived XML	Presentation
`\emph{bird}`	`<emph>bird</emph>`	bird
`\latex;`	`<latex/>`	LaTeX
`\frac{2}{3}`	`<frac><num>2</num>`	{2}/{3}
	`<den>3</den></frac>`
`\label[:`	`<label`	(invisible)
`series="n"]{}`	`series="n"></label>`

20. Gamma Function: Its Weierstrass Product

INT[_{0}^{INFTY} t^{x} e^{-t} {d t}/{t} ] = {1}/{x} PROD[_{k = 1}^{INFTY}{

(

1 + {1}/{k}

)

^{x}}/{

(

1 + {x}/{k}

)

} ]

21. Markup for the Gamma Identity

Regular GELLMU source for the identity:

\[ \int_{0}^{\infty}

t^x e^{-t} \frac{d t}{t}

\int:

= \frac{1}{x}

\prod_{k=1}^{\infty}

\frac{

\bal{1 + \frac{1}{k}}^x

}{

\bal{1 + \frac{x}{k}}

} \prod: \]

22. Gamma: Derived XML Markup

<displaymath>

<int>

<msub>0</msub>

<msup><infty/></msup>

t<pow>x</pow> e<pow><minus/>t</pow>

<frac>

<numr>d t</numr>

<denm>t</denm>

</frac>

</int>

<equals/>

<frac><numr>1</numr><denm>x</denm></frac>

<prod>

<msub>k<equals/>1</msub>

<msup><infty/></msup>

<frac>

<numr>

<bal>1<plus/>

<frac>

<numr>1</numr>

<denm>k</denm>

</frac>

</bal><pow>x</pow>

</numr>

<denm>

<bal>1 <plus/>

<frac>

<numr>x</numr>

<denm>k</denm>

</frac>

</bal>

</denm>

</frac>

</prod>

</displaymath>

23. Gamma: in MathML

(not by automatic translation)

<math

xmlns="http://www.w3.org/1998/Math/MathML"

class="display" mode="display">

<mrow>

<msubsup>

<mo>&Integral;</mo>

<mrow><mn>0</mn></mrow>

<mi>∞</mi>

</msubsup>

<mrow>

<msup>

<mrow><mi>t</mi></mrow>

<mrow><mi>x</mi></mrow>

</msup>

<mo> </mo>

<msup>

<mrow><mi>e</mi></mrow>

<mrow><mi>-t</mi></mrow>

</msup>

<mo> </mo>

<mfrac>

<mrow><mi>dt</mi></mrow>

<mi>t</mi>

</mfrac>

</mrow>

<mo>=</mo>

<mrow>

<mfrac>

<mrow><mn>1</mn></mrow>

<mi>x</mi>

</mfrac>

<mo> </mo>

<msubsup>

<mo>&Product;</mo>

<mrow><mi>k</mi><mo>=</mo><mn>1</mn></mrow>

<mi>∞</mi>

</msubsup>

<mrow>

<mfrac>

<mrow>

<msup>

<mrow><mfenced>

<mrow>

<mn>1</mn><mo>+</mo>

<mfrac><mn>1</mn><mi>k</mi></mfrac>

</mrow>

</mfenced></mrow>

<mrow><mi>x</mi></mrow>

</msup>

</mrow>

<mrow><mfenced>

<mrow>

<mn>1</mn><mo>+</mo>

<mfrac><mi>x</mi><mi>k</mi></mfrac>

</mrow>

</mfenced></mrow>

</mfrac>

</mrow>

</math>

24. Viewing MathML

Viewing support for MathML in web pages is not yet widely available. The above item can be rendered by:

W3C's Amaya: wprod.html or wprod.xml.
Mozilla's MathML development track: wprod.xml (only).
With special plugin for MSIE: wprod.html (only).

25. Generating MathML from article

Ad hoc wprod.html was made from GELLMU source:
wprod.glm.
The short article form (slide 21) of GELLMU source above could be given automatic translation to MathML.
An automatic translation should go through content MathML and from there to presentation MathML.
An automatic translation would not be under the umbrella of general XML processing.

26. Reliable Generation of MathML

Reliable translation will require:

A substantial non-XML, but XML-aware, parsing of all math zones in a GELLMU source document.

Occasional math parsing hints from authors in their markup.

Desirable, sometimes required:

Source markup labeling of math symbols.
Source markup typing of math symbols.

27. MathML Generation Issues

Will authors cooperate?
Will standard web user agents cooperate?

28. How Were These Slides Made?

There were two sets of slides and, correspondingly, two formatters, one for transparencies formatted by the regular program latex and the other for PP4/PDF web slides formatted by the program pdflatex using a number of packages including ppower4 by Klaus Guntermann of Darmstadt University of Technology. Actually I used a small modification of "pp4slide.sty" named gpp4slide.sty to make things work with the standard slides document class. Both of these work with GELLMU article, and there are slightly different definitions of slide with newcommand in the two.

GELLMU

A Bridge from LaTeX to XML

William F. Hammond

University at Albany Albany, New York (USA) http://www.albany.edu/~hammond CTAN: support/gellmu

TUG 2001, August, 2001

1. Single Source Authoring

Situation Wanted

2. Translating LaTeX

3. Translating HTML

4. Pie in the Sky

5. XML

eXtensible Markup Language

6. XML

7. GELLMU

8. Modes

9. Basic GELLMU for XHTML

10. The Syntatic Translator

11. Syntactic Differences from LaTeX

12. Syntax in Basic Mode

13. Basic GELLMU for XHTML

14. \newcommand with XHTML

15. A CTAN Catalogue Entry

16. CTAN Catalogue XML

17. Advanced GELLMU

18. Why is article ``Didactic''?

19. Advanced GELLMU for article

20. Gamma Function: Its Weierstrass Product

21. Markup for the Gamma Identity

Regular GELLMU source for the identity:

22. Gamma: Derived XML Markup

23. Gamma: in MathML

24. Viewing MathML

25. Generating MathML from article

26. Reliable Generation of MathML

27. MathML Generation Issues

28. How Were These Slides Made?

University at Albany
Albany, New York (USA)
`http://www.albany.edu/~hammond`
CTAN: support/gellmu