Add tdemarkdown part - embeddable lightweight markdown viewing component.

TDEMarkdown is based on the md4c library and using TDEHTML for rendering
its output. For enhanced safety, on HTML widget is turned off everything
we don't need for viewing. It integrates nicely into Konqueror and
supports both Commonmark and GitHub markdown syntaxes.

Signed-off-by: Mavridis Philippe <mavridisf@gmail.com>

Prepare to merge tdemarkdown into tdelibs.

Signed-off-by: Slávek Banko <slavek.banko@axis.cz>

1 files changed, 232 insertions, 0 deletions

diff --git a/tdemarkdown/md4c/test/wiki-links.txt b/tdemarkdown/md4c/test/wiki-links.txt
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+
+# Wiki Links
+
+With the flag `MD_FLAG_WIKILINKS`, MD4C recognizes wiki links.
+
+The simple wiki-link is a wiki-link destination enclosed in `[[` followed with
+`]]`.
+
+```````````````````````````````` example
+[[foo]]
+.
+<p><x-wikilink data-target="foo">foo</x-wikilink></p>
+````````````````````````````````
+
+However wiki-link may contain an explicit label, delimited from the destination
+with `|`.
+
+```````````````````````````````` example
+[[foo|bar]]
+.
+<p><x-wikilink data-target="foo">bar</x-wikilink></p>
+````````````````````````````````
+
+A wiki-link destination cannot be empty.
+
+```````````````````````````````` example
+[[]]
+.
+<p>[[]]</p>
+````````````````````````````````
+
+```````````````````````````````` example
+[[|foo]]
+.
+<p>[[|foo]]</p>
+````````````````````````````````
+
+
+The wiki-link destination cannot contain a new line.
+
+```````````````````````````````` example
+[[foo
+bar]]
+.
+<p>[[foo
+bar]]</p>
+````````````````````````````````
+
+```````````````````````````````` example
+[[foo
+bar|baz]]
+.
+<p>[[foo
+bar|baz]]</p>
+````````````````````````````````
+
+The wiki-link destination is rendered verbatim; inline markup in it is not
+recognized.
+
+```````````````````````````````` example
+[[*foo*]]
+.
+<p><x-wikilink data-target="*foo*">*foo*</x-wikilink></p>
+````````````````````````````````
+
+```````````````````````````````` example
+[[foo|![bar](bar.jpg)]]
+.
+<p><x-wikilink data-target="foo"><img src="bar.jpg" alt="bar"></x-wikilink></p>
+````````````````````````````````
+
+With multiple `|` delimiters, only the first one is recognized and the other
+ones are part of the label.
+
+```````````````````````````````` example
+[[foo|bar|baz]]
+.
+<p><x-wikilink data-target="foo">bar|baz</x-wikilink></p>
+````````````````````````````````
+
+However the delimiter `|` can be escaped with `/`.
+
+```````````````````````````````` example
+[[foo\|bar|baz]]
+.
+<p><x-wikilink data-target="foo|bar">baz</x-wikilink></p>
+````````````````````````````````
+
+The label can contain inline elements.
+
+```````````````````````````````` example
+[[foo|*bar*]]
+.
+<p><x-wikilink data-target="foo"><em>bar</em></x-wikilink></p>
+````````````````````````````````
+
+Empty explicit label is the same as using the implicit label; i.e. the verbatim
+destination string is used as the label.
+
+```````````````````````````````` example
+[[foo|]]
+.
+<p><x-wikilink data-target="foo">foo</x-wikilink></p>
+````````````````````````````````
+
+The label can span multiple lines.
+
+```````````````````````````````` example
+[[foo|foo
+bar
+baz]]
+.
+<p><x-wikilink data-target="foo">foo
+bar
+baz</x-wikilink></p>
+````````````````````````````````
+
+Wiki-links have higher priority than links.
+
+```````````````````````````````` example
+[[foo]](foo.jpg)
+.
+<p><x-wikilink data-target="foo">foo</x-wikilink>(foo.jpg)</p>
+````````````````````````````````
+
+```````````````````````````````` example
+[foo]: /url
+
+[[foo]]
+.
+<p><x-wikilink data-target="foo">foo</x-wikilink></p>
+````````````````````````````````
+
+Wiki links can be inlined in tables.
+
+```````````````````````````````` example
+| A                | B   |
+|------------------|-----|
+| [[foo|*bar*]]    | baz |
+.
+<table>
+<thead>
+<tr>
+<th>A</th>
+<th>B</th>
+</tr>
+</thead>
+<tbody>
+<tr>
+<td><x-wikilink data-target="foo"><em>bar</em></x-wikilink></td>
+<td>baz</td>
+</tr>
+</tbody>
+</table>
+````````````````````````````````
+
+Wiki-links are not prioritized over images.
+
+```````````````````````````````` example
+![[foo]](foo.jpg)
+.
+<p><img src="foo.jpg" alt="[foo]"></p>
+````````````````````````````````
+
+Something that may look like a wiki-link at first, but turns out not to be,
+is recognized as a normal link.
+
+```````````````````````````````` example
+[[foo]
+
+[foo]: /url
+.
+<p>[<a href="/url">foo</a></p>
+````````````````````````````````
+
+Escaping the opening `[` escapes only that one character, not the whole `[[`
+opener:
+
+```````````````````````````````` example
+\[[foo]]
+
+[foo]: /url
+.
+<p>[<a href="/url">foo</a>]</p>
+````````````````````````````````
+
+Like with other inline links, the innermost wiki-link is preferred.
+
+```````````````````````````````` example
+[[foo[[bar]]]]
+.
+<p>[[foo<x-wikilink data-target="bar">bar</x-wikilink>]]</p>
+````````````````````````````````
+
+There is limit of 100 characters for the wiki-link destination.
+
+```````````````````````````````` example
+[[12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901]]
+[[12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901|foo]]
+.
+<p>[[12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901]]
+[[12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901|foo]]</p>
+````````````````````````````````
+
+100 characters inside a wiki link target works.
+
+```````````````````````````````` example
+[[1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890]]
+[[1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890|foo]]
+.
+<p><x-wikilink data-target="1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890">1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890</x-wikilink>
+<x-wikilink data-target="1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890">foo</x-wikilink></p>
+````````````````````````````````
+
+The limit on link content does not include any characters belonging to a block
+quote, if the label spans multiple lines contained in a block quote.
+
+```````````````````````````````` example
+> [[12345678901234567890123456789012345678901234567890|1234567890
+> 1234567890
+> 1234567890
+> 1234567890
+> 123456789]]
+.
+<blockquote>
+<p><x-wikilink data-target="12345678901234567890123456789012345678901234567890">1234567890
+1234567890
+1234567890
+1234567890
+123456789</x-wikilink></p>
+</blockquote>
+````````````````````````````````