WebTeX: A Mark-up Language for WebEQ

2. Using WebEQ with WebTeX
3. Macros
4. The Sizer

2. Using WebEQ with WebTeX

To use WebEQ to put math in a web page, an author puts an applet tag in the HTML source code at the point where the notation should appear. The applet tag tells the browser to start the WebEQ applet, and what equation it should display. The typical WebEQ applet looks like this:

<applet codebase="classes" code="geom.webeq.app.mdraw" width=500 height=100>
<param name=size value=36>
<param name=eq value=" y = x + 1 ">
</applet>

View this applet

WebEQ understands a number of parameters, such as size, which control general aspects of how WebEQ should display an equation. Among other things, these parameters determine whether WebEQ expects mathematical expressions to be described with WebTeX commands, or by some other markup language. By default, WebEQ is configured to expect WebTeX.

This document mostly describes the WebTeX language, which is used to fill in the value of the parameter eq, and a few special applet parameters for use with WebTeX. For general instructions about how to set up and use WebEQ, including the use of general applet parameters, consult the pages on getting started with WebEQ.

3. Macros

In addition to general applet parameters like color, WebEQ understand two parameters designed to be used specifically with WebTeX. As in TeX and LaTeX, you may create macros which allow you to define a keyword that represents a more complicated expression.

The macros parameter is written as follows:

<param name=macros value="\define{\plusfifty}{+ 50}">

Here we have used the \define{}{} command to define a new keyword, \plusfifty, which can then be used in the equation to signify where the symbols

+
50

should be placed. In other words, the new keyword \plusfifty will be replaced by the expression "+ 50". Thus, if the equation markup is

<param name=eq value="y \plusfifty = x \plusfifty ">

the end result is that the applet will display:

y + 50 = x + 50

Macros can also be written using arguments, just as in TeX. WebTeX macros use the symbols #1, #2, #3 and so on to represent the arguments passed to a macro. Thus, the macro definition

<applet codebase="classes" code="geom.webeq.app.mdraw" width=500 height=100>
<param name=macros value="\define{\plusN}[1]{+ #1}">
<param name=eq value="y \plusN{35} = x \plusN{z - w}">
</applet>

produces the output

y + 35 = x + z - w

Note that in the definition of \plusN, the number of arguments is specified in square brackets immediately after the braced expression containing the keyword. Also, notice that when using a macro that accepts arguments, the arguments must always be enclosed in curly braces.

The macrofile parameter is used to specify a file containing macro definitions. The value of the macrofile parameter is actually a URL, so several documents can share the same macro definition file in a central location. For example, if the file "my_macros.def" contains:

\define{\plusfifty}{+ 50}

one could write

<applet codebase="classes" code="geom.webeq.app.mdraw" width=500 height=100>
<param name=macrofile value="my_macros.def">
<param name=eq value="y \plusfifty = x \plusfifty">
</applet>

in a document living in the same directory as "my_macros.def", while a document on another computer might contain an applet call something like this:

<applet codebase="classes" code="geom.webeq.app.mdraw" width=500 height=100>
<param name=macrofile value="http://www.macros.com/my_macros.def">
<param name=eq value="y \plusfifty = x \plusfifty">
</applet>

The Tour of WebEQ includes an example of macros.

4. The Sizer

In general, it can be quite tedious to insert applet tags in the document source for each bit of mathematical notation to be displayed. Among other things, in order to properly align the mathematical notation with the surrounding text, one must determine the height and width of the equation.

A great deal of this work is done automatically by a program provided with the WebEQ system called the Sizer. To use the Sizer, an author prepares an HTML document, including the WebTeX markup in the text. The WebTeX markup is surrounded by dollar signs (e.g. $x=2$) for inline equations, and by escaped brackets (e.g. \[ x=2 \]) for displayed equations. This will be familiar to authors accustomed to preparing LaTeX documents.

Once the source document is complete, the author then runs the Sizer program, which goes through the source file, finds the WebTeX markup, computes the equation sizes, and writes out a final HTML file with the proper WebEQ applet tags included. The Sizer has many options that can be set in order to control what applet parameters are set, and how macros are processed, among other things.

One can think of running the Sizer to produce a final HTML file as being analogous to running TeX to produce a DVI file. WebEQ and the web browser work together to display the output of the Sizer, just as a program like xdvi can be used to display the output of TeX. One of the main differences is that the HTML file produced by the Sizer is still a plain text file that one can look at and edit further by hand if necessary, whereas a DVI file is a binary file that is very difficult to work with.

The Sizer is a very useful aid in producing HTML/WebTeX documents. For more information, see Using the Sizer.

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Last modified: Friday, June 20, 1997