Ralph Corderoy <ra...@inputplus.co.uk> wrote: > > It seems to be removed by the mailing list server > > Yes, I expect Mailman has been configured to strip text/html parts. > Just include it in the plain/text part of your email? Or have your MUA > send it as a text/plain part since it's the HTML we want to see, not the > rendering of it.
Here it is, thank you Ralph! Pierre-Jean. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd";> <html xmlns="http://www.w3.org/1999/xhtml";><head><title>Utroff</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></meta><meta name="generator" content="heirloom nroff -mux"></meta><meta name="date" content="2017-12-03T12:49:06"></meta><link rel="stylesheet" href="style.css" type="text/css" media="screen"></link></head><body> <p>Hello alls,</p> <p>Resuming my little sery of articles, I am explaining today how Utmac is linked to the XML world.</p> <h4>Troff and Xml</h4> <p>We all have in mind the various attempts to produce XML files from a troff document: some aim to be universal, and, dealing with the raw troff requests, can only ouptut non semantic html with hardcoded styles, while others, dedicated to a particular macro, fail to consider the raw troff requests the user may need in his document (cf. the source of ms2html, in which the author comments he is implementing more and more raw troff requests)</p> <p>XML files are nothing else but plain text files with semantic informations. On the other side, a troff document contains structured information which gets its meaning within the context of a macro. When we think at it, we have yet a tool which interprets a troff source within the context of a macro to produce plain text files: nroff. Could we use nroff to produce xml files ? I tried, and it appears that solution works well.</p> <p>The idea is simple: one only has to write a macro file, which interprets all the interface macros (paragraph, headers...), to add XML tags to the output file. For example, here is a simple macro to produce XML paragraphs and headings:</p> <pre><span class="F">.</span><span class="F">de</span> <span class="F">PP</span> <span class="F">.</span> <span class="F">\" first, we close the previous block</span> <span class="F">.</span> <span class="F">\" by printing its recorded tag</span> <span class="F">.</span> <span class="F">if</span> <span class="F">d</span> xml-block <span class="F">\</span><span class="F">\*[</span><span class="F">xml-block</span><span class="F">]</span> <span class="F">.</span> <span class="F">\" Secondly, we define the closing tag for the block</span> <span class="F">.</span> <span class="F">ds</span> <span class="F">xml-block</span> <span class="F"></p></span> <span class="F">.</span> <span class="F">\" and last, we print the openning tag.</span> <p> <span class="F">.</span><span class="F">.</span> <span class="F">.</span><span class="F">de</span> <span class="F">H1</span> <span class="F">.</span> <span class="F">if</span> <span class="F">d</span> xml-block <span class="F">\</span><span class="F">\*[</span><span class="F">xml-block</span><span class="F">]</span> <span class="F">.</span> <span class="F">rm</span> xml-block <h1><span class="F">\</span><span class="F">\$*</span></h1> <span class="F">.</span><span class="F">.</span></pre> <p>Nroff has to be configured to produce a correct xml files: we do not want hyphen, lines don’t need to be adjusted, and, the page length has to be defined correctly.</p> <pre><span class="F">.</span><span class="F">\" page length is one line</span> <span class="F">.</span><span class="F">pl</span> 1v <span class="F">.</span><span class="F">ll</span> 75 <span class="F">.</span><span class="F">\" don’t adjust nor hyphenates</span> <span class="F">.</span><span class="F">na</span> <span class="F">.</span><span class="F">nh</span> <span class="F">.</span><span class="F">\" Ending macro is doc:end</span> <span class="F">.</span><span class="F">em</span> doc:end <span class="F">.</span><span class="F">\" Print header</span> <?xml version="1.0" encoding="UTF-8"?> <span class="F">.</span><span class="F">\" Open the root tag</span> <utmac> <span class="F">.</span><span class="F">de</span> <span class="F">doc:end</span> <span class="F">.</span> <span class="F">\" doc:end needs some more space to output text</span> <span class="F">.</span> <span class="F">pl</span> <span class="F">\</span><span class="F">\n(</span><span class="F">nl</span>u+3v <span class="F">.</span> <span class="F">\" close the previous block</span> <span class="F">.</span> <span class="F">if</span> <span class="F">d</span> xml-block <span class="F">\</span><span class="F">\*[</span><span class="F">xml-block</span><span class="F">]</span> <span class="F">.</span> <span class="F">\" Close the root tag.</span> </utmac> <span class="F">.</span> <span class="F">\" set correct page length</span> <span class="F">.</span> <span class="F">pl</span> <span class="F">\</span><span class="F">\n(</span><span class="F">nl</span>u <span class="F">.</span><span class="F">.</span></pre> <p>Since the fonts are hierarchical and defined as strings in Utmac, they are easy to implement as well.</p> <pre><span class="F">.</span><span class="F">ds</span> <span class="F">font-bold0</span> <span class="F"></B></span> <span class="F">.</span><span class="F">ds</span> <span class="F">font-bold1</span> <span class="F"><B></span> <span class="F">.</span><span class="F">nr</span> <span class="F">f-b</span> <span class="F">0</span> <span class="F">.</span><span class="F">ds</span> <span class="F">B</span> <span class="F">\ER’f-b 1-\En[f-b]’\E*[font-bold\En[f-b]]</span></pre> <p>The only real problem of using nroff to produce xml documents is that — along with troff — it is not easy to deal with automatically inserted spaces. I tried to use .chop and \c, but without reliable results. To solve that problem and escape the possible restricted characters a user may insert in his document (’<’, ’>’, and ’&’), I wrote a small post-processor – <span class="I">postxml</span> –, which translates a custom set of tags to xml special characters. Amongst those tags, a special tag removes newlines:</p> <pre>#[ becomes < #] becomes > #( becomes & #) becomes ; <span class="F">\n#</span>-<span class="F">\n </span>is deleted from the stream, and is used to delete newlines.</pre> <p>So, instead of directly writing xml tags, the nroff macro produces writes those custom tags, which are later translated by postxml. Our paragraph macro becomes:</p> <pre><span class="F">.</span><span class="F">de</span> <span class="F">PP</span> <span class="F">.</span> <span class="F">if</span> <span class="F">d</span> xml-block <span class="F">\{</span><span class="F">\</span> <span class="F">.</span> <span class="F">\" tag to remove unwanted newlines</span> #- <span class="F">.</span> <span class="F">\" closing xml tag</span> <span class="F">\</span><span class="F">\*[</span><span class="F">xml-block</span><span class="F">]</span> <span class="F">.</span> <span class="F">\}</span> <span class="F">.</span> <span class="F">ds</span> <span class="F">xml-block</span> <span class="F">#[/pp#]</span> <span class="F">.</span> <span class="F">\" opening xml tag</span> #[pp] <span class="F">.</span> <span class="F">\" tag to remove unwanted newlines</span> #- <span class="F">.</span><span class="F">.</span></pre> <p>A preprocessor, prexml, escapes the possible presence of those tags in the user document. The troffxml archive, avaible on <a href="http://utroff.org ,"></a> provides prexml, postxml, and a two xsl stylesheet to produce html and fodt (flat open document) files, and Utmac provides the macro ux for that purpose. So, the command to produce xml documents from a troff source is:</p> <pre>prexml <span class="F"><</span> f.tr <span class="F">|</span> nroff -Tlocale -mux <span class="F">|</span> postxml <span class="F">></span> f.xml xsltproc utohtml.xsl f.xml <span class="F">></span> f.html xsltproc utofodt.xsl f.xml <span class="F">></span> f.fodt</pre> <p>Since I believe you want to have a look at the result, you will find, joined to this mail, its xml, html, and fodt versions as produced by this system (which reveals the fodt code block needs some more work...).</p> <p>On my next mail about Utmac, I will present you some goodies.</p> <p>Kind Regards, Pierre-Jean</p> </body></html>
