Formatting primitives

This section contains some important notes on formatting primitives which are not really part of the style-sheet language, but nevertheless very related.

First of all, most TeXmacs presentation tags can be divided in two main categories: inline tags and block tags. For instance, frac is a typical inline tag, whereas theorem is a typical block tag. Some tags, like strong are inline if their argument is and block in the contrary case. When writing macros, it is important to be aware of the inline or block nature of tags, because block tags inside a horizontal concatenation are not rendered in an adequate way. If you need to surround a block tag with some inline text, then you need the surround primitive:

In this example, we surrounded the body of the theorem with the bold text “Theorem.” at the left hand side and a “right-flush” at the right-hand side. Flushing to the right is important in order to make the blue visual border hints look nice when you are inside the environment.

In most cases, TeXmacs does a good job in determining which tags are inline and which ones are not. However, you sometimes may wish to force a tag to be a block environment. For instance, the tag very-important defined by

may both be used as an inline tag and a block environment. When placing your cursor just before the with-tag and hitting return followed by backspace, you obtain

Since the body of the macro is now a block, your tag very-important will automatically become a block environment too. In the future, the drd-props primitive will give you even more control over which tags and arguments are inline and which ones are block.

Another important property of tags is whether they contain normal textual content or tabular content. For instance, consider the definition of the standard eqnarray* tag (with a bit of presentation markup suppressed):

The use of surround indicates that eqnarray* is a block environment and the use of tformat specifies that it is also a tabular environment. Moreover, the twith and cwith are used to specify further formatting information: since we are a block environment, we enable hyphenation and let the table span over the whole paragraph (unused space being equally distributed over the first and last columns). Furthermore, we have specified that the table contains exactly three columns.

Finally, it is important to bear in mind that style-sheets do not merely specify the final presentation of a document, but that they may also contain information for the authoring phase. Above, we have already mentioned the use of the right-flush tag in order to improve the rendering of visual border hints. Similarly, visual hints on invisible arguments may be given in the form of flags:

More generally, the specific tag with first argument “screen” may be used to display visual hints, which are removed when printing the document.