phil ringnalda

Attention blogging toolmakers who want to do a smart convert breaks (Marcus, I think that’s you and only you):

One more to add to the list of things where you shouldn’t convert line breaks to <br> or <br />: <pre> through </pre>

Background:

As typically implemented by blogging tools, “convert line breaks” is boolean: either every single newline in the post is converted to an HTML break character or no newlines are converted. Almost every novice or non-geeky user, and most experienced geeky users, will use “convert line breaks,” because it’s a pain to have to insert your own <p>, </p>, and <br /> tags. That’s fine up until the user wants to post a table, list, form, select, or preformatted section. Virtually nobody enters tables or lists as a single line, instead entering:

<table>
<tr>
<td>
Cell one
</td>
<td>
Cell two
</td>
</tr>
<tr>
<td>
Row two
</td>
<td>
Cell four
</td>
</tr>
</table>

which “convert line breaks” turns into:

<table><br>
<tr><br>
<td><br>
Cell one<br>
</td><br>
<td><br>
Cell two<br>
</td><br>
</tr><br>
<tr><br>
<td><br>
Row two<br>
</td><br>
<td><br>
Cell four<br>
</td><br>
</tr><br>
</table><br>

a glob of invalid HTML which browsers typically display by putting some, if not all, of the breaks first, and then showing the table. That’s not what the typical novice user expects when she pastes in the table code for yet another “What * are you” quiz. For that matter, having a <pre> section double-spaced isn’t what the typical experienced user expects—it took me several rebuilds to realize what was happening.

What shouldn’t be converted:

Ideally, a smart convert line breaks would not convert any breaks between <pre> and </pre>, and within a table or list would only convert line breaks in text, but not after tags. For example,

<td>
a line
a nother
</td>

should be converted to

<td>
a line<br />
a nother
</td>

but that might be a little too expensive to implement. For a simple, fairly smart convert line breaks, just skip over anything between <table and </table>, <(ol|ul|dl) and </(ol|ul|dl)>, <pre and </pre>, <select and </select>, and <form and </form>. For a fully smart version, don’t convert a newline immediately after start or end tags for any of:

p
br
table
caption
colgroup
col
thead
tfoot
tbody
tr
td
th
dl
dt
dd
li
ol
ul
blockquote
form
fieldset
legend
label
select
optgroup
option

Now if only I could figure out where Movable Type actually does its conversion, I could try hacking in a huge regexp to match those, and see just how slow it would be.