$keepHTML = false does not work with all tags

A simple test case.

I did a bit more digging and this bug is in the parser.

When running the following code:
<?php
function getNodeInfo($parser) {
return array(
'nodeType' => $parser->nodeType,
'tagName' => $parser->tagName,
'node' => $parser->node,
);
}

function debugParser($html) {
$parser = new parseHTML;
$parser->html = $html;

$nodes = array();
while($parser->nextNode()) {
$nodes[] = getNodeInfo($parser);
}

echo $html.PHP_EOL;
var_export($nodes);
echo PHP_EOL;
echo PHP_EOL;
}

debugParser('<div>some text</div>');
debugParser('<article>some text</article>');
?>

The output shows that the second case was not parsed correctly:
<div>some text</div>
array (
0 =>
array (
'nodeType' => 'tag',
'tagName' => 'div',
'node' => '<div>',
),
1 =>
array (
'nodeType' => 'text',
'tagName' => NULL,
'node' => 'some text',
),
2 =>
array (
'nodeType' => 'tag',
'tagName' => 'div',
'node' => '</div>',
),
)

<article>some text</article>
array (
0 =>
array (
'nodeType' => 'text',
'tagName' => '',
'node' => '&lt;article>some text',
),
1 =>
array (
'nodeType' => 'text',
'tagName' => '',
'node' => '&lt;/article>',
),
)

I was able to work around the issue for my use case by adding some tags to the arrays in the parseHTML class. For posterity I've attached a patch with my changes (this is undertested, but it seems to work for me).

If Markdownify ever undergoes active development again, I'd recommend ditching the custom parser in favor of something more established/robust. This StackOverflow answer discusses many options: http://stackoverflow.com/a/3577662/3625

Patch to make HTML parser able to handle more elements.