{"id":482,"date":"2010-09-22T15:33:49","date_gmt":"2010-09-22T10:03:49","guid":{"rendered":"http:\/\/www.cvr.cc\/?p=482"},"modified":"2010-09-22T15:33:49","modified_gmt":"2010-09-22T10:03:49","slug":"tex4ht-low-level-commands","status":"publish","type":"post","link":"https:\/\/cvr.cc\/?p=482","title":{"rendered":"TeX4ht: Low-level Commands"},"content":{"rendered":"

There are four commands which are very useful to write custom configuration for Te<\/span>X4ht. They are: <\/p>\n

    \n
  1. \\NewConfigure<\/code><\/li>\n
  2. \\Configure<\/code><\/li>\n
  3. \\HCode<\/code><\/li>\n
  4. \\Tg<\/code><\/li>\n<\/ol>\n

    Te<\/span>X4ht does not redefine environments or macros, instead, it inserts hooks<\/em> into the definitions so that the original definitions remain undisturbed while hooks helping to insert HTML<\/small> code at appropriate locations of content in the desired way. Hooks are nothing but macros which will expand to target markup as per our dictates. The \\NewConfigure<\/code> and \\Configure<\/code> commands allow us to seed the hooks into the original definitions. Let us look at an example.<\/p>\n

    \n  \\def\\one#1#2#3{#1\\space#2\\space#3}\n<\/pre>\n
    We have a macro one<\/code> which takes up three arguments. Now, suppose that we want to insert custom HTML<\/small> elements at the<\/p>\n
      \n
    1. beginning of all arguments<\/li>\n
    2. end of all arguments<\/li>\n
    3. between first and second arguments<\/li>\n
    4. between second and third arguments<\/li>\n<\/ol>\n
      We shall make use of \\NewConfigure<\/code> command to define hooks.<\/p>\n
      \n \\NewConfigure{one}[4]%\n     {\\def\\a@one{#1}\\def\\b@one{#2}%\n      \\def\\c@one{#3}\\def\\d@one{#4}}\n<\/pre>\n
      The syntax is<\/p>\n
      \n  \\NewConfigure{name}[i]{body}\n<\/pre>\n
      where name<\/em> is the name of macro without the backslash, i<\/em> is the number of hooks and body<\/em> is where we define all the hooks. In the example, we want to define four hooks for the macro \\one<\/code>. Hence, we assign the first hook to \\a@one<\/code> (you can choose any name you like), second to b@one<\/code>, so on and so forth. Then, we define another macro similar to \\one<\/code> with three arguments and insert the pre-defined hook macros at appropriate locations. So the definition starts with \\a@one<\/code> and ends with \\b@one<\/code> hooks. \\c@one<\/code> is inserted in between arguments #1<\/code> and #2<\/code>. \\d@one<\/code> is inserted between the arguments #2<\/code> and #3<\/code>. Once \\@tempa<\/code> is defined, we then equate \\one<\/code> with \\@temp<\/code> with a \\let<\/code> command. See the code below:<\/p>\n
      \n  \\def\\@temp#1#2#3{\\a@one#1\\c@one#2\\d@one#3\\b@one}\n   \\let\\one\\@tempa\n<\/pre>\n
      Now, comes the real meat of the configuration process wherein we make use of \\Configure<\/code> command to insert required HTML<\/small> markup.<\/p>\n
      \n  \\Configure{one}\n   {\\Tg<span class=\"one\">\\Tg<code>}{\\Tg<\/b>\\Tg<\/span>}\n   {\\Tg<\/code>\\Tg<em>}{\\Tg<\/em>\\Tg<b>} \n<\/pre>\n
      The above configuration inserts <span class<\/code>“one”>= in the beginning and the corresponding closing element, <\/span><\/code> gets inserted in the end, <code><\/code> element is inserted after <span><\/code> to make the strings in first argument verbatim, <\/code><em><\/code> added after first argument which closes the verbatim mode and starts an emphasize for second argument, <\/em><b><\/code> are inserted between second and third which close the emphasize and start a bold face, in the end we close the <\/b><\/code> to complete the bold facing of third argument. Let us try this on a typical example of \\one<\/code>:<\/p>\n
      \n  one{verbatim}{emphasize}{boldface}\n<\/pre>\n
      As you might have guessed, Te<\/span>X4ht will generate following HTML<\/small> from above source:<\/p>\n
      \n  <span class=\"one\">\n   <code>verbatim<\/code>\n   <em>emphasize<\/em>\n   <b>boldface<\/b>\n  <\/span>\n<\/pre>\n
      If you want to insert necessary css<\/code> code to interpret <span class=\"one\"><\/code>, you might add the following line somewhere in your document or configuration file:<\/p>\n
      \n  \\Css {.one {<your css code >}}\n<\/pre>\n
      \n\n<\/p>\n
      \\HCode<\/code> and \\Tg<\/code><\/h4>\n
      These are the two commands used in Te<\/span>X4ht to insert target markup elements as \\special<\/code>s into the dvi<\/code> file which are then extracted while post-processing with tex4ht<\/code> binary program. \\Tg<\/code> has the following syntax:<\/p>\n
      \n  \\Tg<#1>\n<\/pre>\n
      Between the angle brackets, you might add whatever markup you need to insert. The examples sited above to explain the functionality of \\Configure<\/code> command make use of \\Tg<\/code>. It is fit for inserting a single element with or without attributes. The angle brackets act as delimiters.<\/p>\n
      The functionality of \\HCode<\/code> command is also the same, except that there are no delimiters, which allows one to insert any kind of arbitrary code as arguments to \\HCode<\/code>.<\/p>\n
      \n  \\HCode{<section id=\"}%\n    \\stepcounter{sctr}sec.\\thesctr%\n   \\HCode{\">}\n<\/pre>\n
      This will generate the following HTML<\/small> element in the output, assuming that we have 9<\/code> as the value for \\thesctr<\/code>:<\/p>\n
      \n  <section id=\"sec.9\">\n<\/pre>\n
      Te<\/span>X4ht has already defined \\Configure<\/code> with different numbers of hooks for commonly used commands in La<\/small><\/span>Te<\/span>X and several popular packages used in La<\/small><\/span>Te<\/span>X. However, if you want to manipulate any of the default structure or want to add extra functionality over those already available, \\NewConfigure<\/code> comes handy and above explanation might be of help to explore further.<\/p>\n","protected":false},"excerpt":{"rendered":"
      There are four commands which are very useful to write custom configuration for TeX4ht. They are:<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[21,23,29,17],"tags":[],"class_list":["post-482","post","type-post","status-publish","format-standard","hentry","category-configure","category-hcode","category-newconfigure","category-tg"],"_links":{"self":[{"href":"https:\/\/cvr.cc\/index.php?rest_route=\/wp\/v2\/posts\/482","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cvr.cc\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cvr.cc\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cvr.cc\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cvr.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=482"}],"version-history":[{"count":0,"href":"https:\/\/cvr.cc\/index.php?rest_route=\/wp\/v2\/posts\/482\/revisions"}],"wp:attachment":[{"href":"https:\/\/cvr.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=482"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cvr.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=482"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cvr.cc\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=482"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}