Template:Citation/make link

This template is a "subroutine" of Citation/core used for conditionally making links for the  and   fields in a citation.

It is invoked as:
 *  

It uses the following algorithm:
 * 1) If the first parameter is empty, it returns the second parameter as plain text.
 * 2) If the first parameter is a URL, it returns the second parameter wrapped inside an external link to the first.

This "subroutine" is designed for Citation/core and makes assumptions that may not be valid elsewhere.

Examples:
 * " " produces "".
 * " " produces "".