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XMLmind DITA Converter Manual

  

Chapter 7. Fancy code blocks Previous topic Parent topic Child topic Next topic

This section explains how you can automatically add line numbers, “expand” tab characters and colorize the source code contained in <pre>, <codeblock> or any other element specializing <pre>.

Adding line numbers, “expanding” tab characters and colorizing the source code contained in <pre>, <codeblock> or any other element specializing <pre> is done by adding one or more of the following classes to the @outputclass attribute of this element:
line-numbers
line-numbers-N (where N is an integer > 0)
show-line-numbers
Give a number to the lines contained in the <pre> element.
By default, first line number is 1. This first line may be specified using the second form of the line-numbers class, for example, line-numbers-100 specifies that lines are to be numbered and that first line number is 100.
show-line-numbers, an alias for line-numbers-1, is also accepted for compatibility with the DITA-OT Opens in new window.
language-L (where L is language name)
Colorize the source code contained in the <pre> element. L, a “programming language” such as c, java, css, xml, specifies how the source code should be colorized.
More information about this feature, commonly called syntax highlighting, in next section.
tab-width-W (where W is an integer >= 0)
normalize-space
Specifies whether tab characters should be expanded to a number of space characters. W is the maximum number of space characters for an expanded tab character, hence this value specifies the location of “tab stops”. Examples: tab-width-4 means: expand tabs to up to 4 space characters; tab-width-0 means: do not replace tabs by space characters.
In addition to replacing tab characters by a number of space characters, tab-width-W (where W > 0) also removes the space characters which are common to the beginning of all text lines. That is, it removes the superfluous “indentation” in the <pre> element, if any. See example below.
Moreover tab-width-W (where W > 0) also removes the (useless) space characters found just before newline characters.
normalize-space, an alias for tab-width-8, is also accepted for compatibility with the DITA-OT Opens in new window.
Remember
Remember
When the <outputclass> attribute of any element specializing <pre> contains class line-numbers/line-numbers-N and/or class language-L , then class tab-width-8 is implicitly specified too, that is, whitespace normalization is automatically performed. If this is not what you want, please explicitly add class tab-width-0 to @outputclass.

§ Example: a simple C program featuring line numbering and syntax highlighting

In the following C program, lines are indented using tab characters.
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<pre class="language-c line-numbers tab-width-4">/* Hello World */
#include &lt;stdio.h&ght;

int main()
{
        printf("Hello World\n");
        return 0;
}</pre>
is rendered as:
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/* Hello World */
#include <stdio.h>

int main()
{
    printf("Hello World\n");
    return 0;
}

§ Example: superfluous indentation is removed by tab-width-N (where N > 0)

Attribute @outputclass implicitly also contains tab-width-8. First line "    /tmp/" starts with 4 space characters.
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<pre outputclass="line-numbers">    /tmp/
    /usr/                            
        bin/
        lib/
        <b>local/</b>
                <b>bin/</b>
                <b>lib/</b>
                <b>src/</b>
        src/
    /var/                            
</pre>
is rendered as:
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/tmp/
/usr/
    bin/
    lib/
    local/
            bin/
            lib/
            src/
    src/
/var/