man — on line help XML file description format


The on line help source files are written in XML.

Source files (with extension .xml) can be found in the <SCIDIR>/man/<language>/* directories. The file name is usually associated to a keyword (corresponding to a function name most of the cases) it describes.

A few words about XML

An XML file resembles to an HTML file but with both a more rigid and free syntax. Free because you may build your own tags: the set of tags together with its rules must be described somewhere, generally in another file (<SCIDIR>/man/manrev.dtd for scilab), and rigid because, once the tags and rules are defined (which are called the Definition Type Document: DTD) , you must respect its (in particular to every open tags <MY_TAG> must correspond a closed </MY_TAG>).

The DTD manrev.dtd is written in SGML and precises the exact syntax required by a scilab XML help page. So if you know this language you may red this file. The following annotated example (see the next section) shows you some possibilities offered by this DTD and may be enough to write simple help pages.

Once an XML page is written and conforms to the DTD, it may be transformed in HTML to be red by your favorite browser or by the tcltk scilab browser (see section browser choice in this page). The XML -> HTML translation is controled by a set of rules written in the (XML) file <SCIDIR>/man/language/html.xsl. Those rules are currently more or less restricted to fit the tcltk scilab browser features (which may display correctly only basic HTML): if you use a real HTML browser and want a better appearance you have to modify this file.

How to write a simple xml scilab help page: the lazzy way

If one want to write the xml file associated to a new scilab function he or she may use the Scilab function help_skeleton to produce the skeleton of the xml file. In most cases the user will not be required to know xml syntax.

How to write a simple xml scilab help page: an example

Here is a simple annotated XML scilab help page which describes an hypothetic foo scilab function. In the following, the XML file is displayed in a type writer font and cut-out in several parts, each part being preceded by some associated explanations. The entire XML file foo.xml is in the <SCIDIR>/man/eng/utility directory and the result may be displayed by clicking on foo. (you may found others examples in the <SCIDIR>/examples/man-examples-xml directory). Finally note that some tag pairs <TAG>, </TAG> have been renamed here <ATAG>, </ATAG>. This is because some scilab scripts which do some work on or from the xml files don't verify if a tag is inside a VERBATIM entry.

The 3 first lines of the file are mandatory, the second precises the path to the DTD file and the third, formed by the <MAN> tag, begin the hierarchical description (the file must finish with the </MAN> tag). The 4 followings entries : LANGUAGE, TITLE, TYPE and DATE, are also mandatory (in this order) the text corresponding to <TYPE> being generally 'Scilab function' (most of the cases) but may be simply 'Scilab keyword' or 'Scilab data type', ..., depending of what explains the help page.

<!DOCTYPE MAN SYSTEM "<SCIDIR>/man/manrev.dtd">
   <TYPE>Scilab function</TYPE>

The first of these 2 following entries (SHORT_DESCRIPTION) is mandatory and important since the words of the short description text, are used by the apropos command to search help pages from a keyword: the short description is used to build the whatis.html file corresponding to your toolbox and the apropos keyword command looks in all the whatis files and then proposes the links to every page containing the word keyword in its short description (in fact the actual associated tags are <SHORT_DESCRIPTION> and </SHORT_DESCRIPTION> and not <ASHORT_DESCRIPTION> and </ASHORT_DESCRIPTION>). The next entry (CALLING_SEQUENCE) must be used if you describe a function (but is not strictly mandatory). If your function have several calling sequences use several CALLING_SEQUENCE_ITEM entries.

          <ASHORT_DESCRIPTION name="foo">foo short description</ASHORT_DESCRIPTION>

The following entry (PARAM) is not strictly mandatory but is the good one to describe each parameters (input and output) in case of a function.

                      <SP>: what may be x</SP>
                      <SP>: what may be y</SP>

The DESCRIPTION entry is perhaps the most significant one (but not strictly mandatory) and may be more sophisticated than in this example (for instance you may have DESCRIPTION_ITEM sub-entries). Here you see how to write several paragraphes (each one enclosed between the <P> and </P> tags), how to emphasis a variable or a function name (by enclosing it between the <VERB> and </VERB> tags), how to emphasis a part of text (<EM> or <BD> and <TT> to put it in a type writer font)), and finally, how to put a link onto another help page (in fact the actual associated tags are <LINK> and </LINK> and not <ALINK> and </ALINK>).

                A first paragraph which explains what computes the foo function.
                If you want to emphasis a parameter name then you use the following
                tag <VERB>x</VERB>, if you want to emphasis a part of text
                <EM>inclose it inside theses tags</EM> and use theses ones
                <BD>to have a bold font</BD> and finally <TT>for a type writer style</TT>.
                A second paragraph... Here is an example of a link to another page :

Here is how to write your own entry, for instance to describe some outside remarks and/or notes about your wonderful function.

         <SECTION label='Notes'>
                Here is a list of notes :
             <ITEM label='first'><SP>blablabla...</SP></ITEM>
             <ITEM label='second'><SP>toto is the french foo...</SP></ITEM>

An important entry is the EXAMPLE one which is reserved to show scilab uses of your function (begin with simple ones !). Note that you must close this entry with ]]></EXAMPLE> and not like here with }}></EXAMPLE> (once again this is a bad trick to avoid some interpretation problems).

             deff("y=foo(x)","y=x"); // define the foo function as the identity function

This last part explains how to put the links onto others related help pages (as said before the good tags are in fact <LINK> and </LINK> and not <ALINK> and </ALINK> ) and finally how to reveal your name if you want (use one AUTHOR_ITEM entry by author). Perhaps it is a good idea to put an email adress if you look for bug reports !

           <SEE_ALSO_ITEM> <ALINK>apropos</ALINK> </SEE_ALSO_ITEM>


How to create an help chapter

Create a directory and write down a set of xml files build as described above. Then start Scilab and execute xmltohtml(dir), where dir is a character string giving the path of the directory (see xmltohtml for more details) .

How to make Scilab know a new help chapter

This can be done by the function add_help_chapter.


    function y=foo(a,b,c),y=a+2*b+c,endfunction
    if (isdef('editor') | (funptr('editor')<>0)) then

See Also

apropos , help , help_skeleton