Markup

April 2011

Markup languages are fundamentally different from programming languages, in form, not just in function. Programming languages tell. Markup languages show, and tell what can’t be shown.

For a text-based markup language, it seems natural that plain text would, by default, be valid and display more-or-less as normal. Of course, the special markup delimiters would need to be escaped, but ideally, that should only be one or two uncommon characters, and the escape sequence should be easy to use.

So why does HTML ignore whitespace? That may be good for programming languages, but it sounds less than ideal for a markup language.

This criteria disqualifies S-expressions from markup applications, too.