Routine HTMLClasses

Argument

Options., a stem. The following tails are examined:

• Options.assignment, for (extended) assignment operator characters and character sequences.
• Options.constant, for strings or symbols taken as a constant.
• Options.operator, for operator characters and operator character sequences.
• Options.special, for special characters and special character sequences.
• Options.classprefix, a prefix prepended to every HTML class. The default is "rx-".

The routine code assigns one or two HTML classes to every element category, and, in the case of symbols taken as a constant, to every element subcategory.

When two classes are assigned, the first one is generic (for instance, "spe" for special characters), and the second one identifies the corresponding element (for example, "comma", or "colon").

The value of the corresponding compound variables determines the class associated with every element category and subcategory, in the following way:

• When the value is "group", only the generic class is assigned.
• When the value is "detail", only the detailed class is assigned.
• When the value is "full", two classes are assigned, the generic one and the detailed one (in this order).

Returns

A stem ("HTMLClass") mapping element categories and subcategories to html classes. The default HTML class is "rexx".

Program logic

Irrespective of the whether we are producing output for ANSI terminals, HTML, or LaTeX, the Highlighter assigns one or more HTML class names to every element category and subcategory. This assignment is done in the HTMLClasses routine, which can of course be customized.

In many cases, an element category is mapped directly to a single HTML class. For example, .EL.SHEBANG, the category that identifies shebang lines, is assigned the class "shb".

In many other cases, an element category is mapped to two HTML classes: the first is a generic one, which is the same for a whole set of elements, and the second one is a more specialized one. For example, .EL.OP.MULTIPLICATION, which identifies The "*" operator, is assigned a generic class of "op", for "operator", and a specialized class of "mul".

These class names are then prefixed with a special prefix (by default, "rx-" is used) to avoid conflicts with classes by other programs. In our example, the "*" operator would be assigned classes "rx-op" and "rx-mul".

Coarse- vs. fine-grained class assignments

The sets of elements that are capable of being assigned two classes instead of only one are assignments ("asg" + a specific class), operators ("op" + a specific class), special characters and special character sequences ("spe" + a specific class) and taken constants ("const" + a specific class).

Depending on the supplied program options, each run of the Highlighter may assign to the elements belonging to each of these sets the first, generic class, the second, more specialized class, or both.

For example, when using rexx fenced code blocks, the assignment attribute may have a value of "group" (the first class), "detail" (the second class), or "full" (both).

This mechanism allows to choose, for every element set, between very fine-grained and more coarse-grained class assignments on a highlighter run-by-run basis.

~~~rexx {assignment=detail special=group operator=full constant=detail classprefix="P"}

Program source