Wrap email quotes with html element

Question

I'm wondering if I could handle the following situation with a single function or regex call. Given the folowing input:

Some text
> Foo
> Bar
>> Baz
> Foo

The output should be:

Some text
<blockquote>
Foo
Bar
 <blockquote>
 Baz
 </blockquote>
Foo
</blockquote>

The following two functions do handle this situation, but I think there must be a more elegant way to handle it. I thought about regular expressions, but could not think of any pattern that replaces the input with the output (see above).

<?php
function toArray($str, $currLevel = 0, $i = 0) {
 $return = array();
 $lines = explode("\n", $str);
 for($j = count($lines); $i < $j; $i++) {
 $line = trim($lines[$i]);
 $level = preg_replace('/^((?:>|\s)+).*/','1円', $line);
 $level = substr_count($level, '>');
 if($level == $currLevel) {
 array_push($return, preg_replace('/^((?:>|\s)+)(.*)/','2円', $line));
 }
 else if($level > $currLevel) {
 array_push($return, toArray(join("\n", $lines), $currLevel + 1, &$i));
 } else if($level < $currLevel) {
 $i--;
 return $return;
 }
 }
 return $return;
}
function toQuote($lines) {
 $return = "<blockquote>\n";
 foreach($lines as $line) {
 if(is_array($line)) {
 $return .= toQuote($line);
 }
 else {
 $return .= $line . "\n"; 
 }
 }
 $return .= "</blockquote>\n";
 return $return;
}
$str = <<<INPUT
 Some text
 > Foo
 > Bar
 >> Baz
 > Foo
INPUT;
echo toQuotes(toArray($str));

• Sam Wilson: Don't know if it's of any help, but Markdown does this; however, only with a newline after the inner quote.

Answer 1

This isn't much more elegant, but maybe you like it:

$text = "Some text
> Foo
> Bar
>> Baz
> Foo
";
function clean($text) {
 $result = "";
 $lines = explode("\n", $text);
 foreach($lines as $key => $line) {
 $lines[$key] = preg_replace('/(>)+ /', '', $line);
 }
 return join("\n", $lines);
}
function quotes($text, $level = 1) {
 $search = str_repeat(">", $level);
 $fstpos = strpos($text, $search);
 $sndpos = strrpos($text, $search);
 $sndpos = strpos($text, "\n", $sndpos);
 $middle = substr($text, $fstpos, $sndpos + 1);
 if($fstpos === false or $sndpos === false)
 return clean($middle, $search);
 $fst = clean(substr($text, 0, $fstpos), $search);
 $snd = clean(substr($text, $sndpos), $search);
 return $fst . "<blockquote>\n" . quotes($middle, $level + 1) . "</blockqoute>" . $snd;
}
echo quotes($text);