how to compose URLs?

[Rich Morin]

Let's say that I want to create a link to a Wikipedia article.

I can do this using either a regular or a reference link:

[Markdown](https://en.wikipedia.org/wiki/Markdown)

[_wp_md1]: https://en.wikipedia.org/wiki/Markdown

...

[Markdown][_wp_md1]

However, if I'm linking to a lot of Wikipedia articles, I'd like to reduce the clutter even further.

Problem is, I can't find a way to compose URLs from (say) abbreviations.

For example, this doesn't work:

*[_wp]: https://en.wikipedia.org/wiki

[_wp_md2]: _wp/Markdown

...

[Markdown][_wp_md2]

Am I missing something?

-r