8 Jan 2010 aephea-base 1.002, 10-008
aephea-base — a description of Aephea base definitions
The macros in this package have been ported to both HTML and troff.
aephea-base — A description of Aephea base definitions. The macros in this package have been ported to both HTML and troff. This package is used by the Aephea simpledocument class and by the Portable Unix Documentation (PUD) mini-languages for authoring manual pages (pud-man) and the PUD language for FAQ authoring (pud-faq).
There is a small list of known issues in the ISSUES section, mostly concerning the troff device. These should generally be of no concern at all, but if you run into trouble look there first. A quick glance through the list before you run into trouble may be the wisest thing to do.
The itemize environemnt is the Aephea workhorse for lists, enumerations, itemizations, and other tailed creatures. A simple and valid use is for example
This source result in the following output:
For I am foo.
For we are bar and zut.
This is not impressive at all, but it gives an idea of how itemize works. The following example is a single itemize environment providing a rollercoasterride through most of the features of the itemize environment. As shown below, it is possible to change all the itemize settings and styles at will even within a single itemize instance. Of course this is not useful at all except for demonstrating the itemize capabilities, but it goes to show that the itemize macros are quite robust (by virtue of modularity).
NOTE
The entire listing below was put in Aephea's spacing environment,
described further below. The environment was used to create
extra margins on the two sides.
Spacing modes compact and cascade are determined by the key flow. The current mode is compact, meaning that the itemize token and the ensuing text are on the same line. Below, compact mode is switched off (approximately) halfway. The interitem key determines the amount skipped between an item description and the next item.
Several item modes (custom, mark, enumeration).
Several enumeration modes (roman, arabic, alphabetic).
The style of a list can be changed while in the middle of it.
Nuther item.
The list can be 'interupted' and resumed (by means of the \intermezzo#1 macro).
Items can be optionally and automatically right and/or left delimited. The current item is delimited with square brackets.
Items can be left or right aligned.
Items can be stacked, which is supported only when flow is set to cascade.
Beginning with this item, flow is set to cascade.
is now possible.
(back to right-align) The itemcounter just keeps running by the way.
(back to compact) But the counter can be manipulated at will.
A bullet item.
Now interitem is set to 0 (affecting the current list), and a new list is started contiguous to the present text (by having its margintop set to 0).
Hubris
Laziness
Impatience
Are the three virtues of programming.
This concludes a listing showing most of the itemize capabilities.
You steer the itemize environment by providing it with tag-value pairs like so:
This is the list of tags that you may use.
Top of table, anomalous unit (ems), default 0.
Paragraph skip in ems inbetween items, default 0.
Set to compact or cascade
Width of text indent in ems.
Width of item margin in ems (for right-aligned items).
E.g. \*{itembullet} (if type=mark), affects \item.
One of left or right (item alignment), default left.
class name assigned to all block-level elements
What's printed immediately to the left of an item.
What's printed immediately to the right of an item.
One of mark, roman, abc, arabic, affects \item.
The count of items seen so far, e.g. 13 right now.
You need to know that the itemize environment internally maps these tags to dollar keys simply by prepending a dollar. Thus, if you want to reset one of the values associated with such a tag, you need to do e.g.
A more robust to do this is to ensure that the modified key is retrieved from the right dictionary, i.e. the top-level itemize dictionary, as follows.
Its syntax is identical to that of the itemize environment. It accepts tags left, right, top, and bottom. These should receive numeric values. The associated unit is em.
The troff device does not yet support the top and bottom tags.
\enref#2 creates a link for which the first argument is the anchor and for which the second argument is the content (which can be left empty). \iref#2 takes such an anchor as the first argument and it takes content that carries the link as the second argument. \lref#2 takes a file name (possibly including a relative or absolute path) as the first argument and content as the second argument. \aref#2 takes a URL (later possibly a URI) as the first argument and content as the second argument. \sibref#2 takes a label as argument which presumably is the name of some application. It may append an extension depending on the current device, and it assumes that label + extension is the name of a file in the current directory. The second argument is displayed in the text. For \sibref#1 the displayed text is the same as the label. For \sibref#3 the second argument is an additional anchor within the file being linked to, and the third argument is the displayed text. \httpref#1 simply prints a URL which will be active when html is output.
These are all paragraph macros that carry the paragraph content as the last argument. The first argument of \cpar#2 and \ccar#2 is the caption. These macros will ensure well-formedness for devices that support it, such as HTML. Use \car#1 where you don't need a paragraph skip, but just need to indicate that you are in text mode again. You can simply always use \par#1 and never use \car#1. If you care about the details of spacing though, or if you have particular trouble for example in creating an itemize environment where you do not want top and bottom margins, then it could be worthwile to turn to \car#1. Examples for using \car#1 are:
After an environment that always carries a bottom margin.
After an environment that does not carry a bottom margin, and where you specifically want the environment to be contiguous to the enclosing text. The listing you are currently reading is an example of this.
As promised. The \car macro may feel a little unusual. If you don't mind standing the chance of a little spurious vertical white-space just use \par all the time. If you really need it, such as in an 'inline' listing as above, the \car macro is ready to do the job.
The first four items set their argument in the font specified. \tt#1 and \v#1 both denote a typewriter font. These macros should not be nested if troff is to be among the output devices. Support for the last two items is not yet very robust. They temporarily increment respectively decrement the font by the amount of the first argument and apply the resulting setting to the second argument.
Make the device output the contents verbatim in a mono-spaced font, obeying spaces and newlines. This does not prohibit expansion of macros, use \protect#1 for that. The macro \verbatim#1 will create a non-breaking environment.
Do not nest \bf#1, \it#1, \tt#1, or \v#1 macros if troff is among the output devices. It will yield unexpected results.
Do not use fractional values for textindent and itemmargin in the itemize environment, if troff is among the output devices. The reason is that the Aephea macros use the difference between these two values and pass them on to the output devices. Troff rounds all values it gets and thus the additive relationship between the values may be lost.