Template:Convert/numdisp/doc

The Template:Convert/numdisp processes a number, for display, by checking to display a fraction part (at "/"), else it just uses parser-function 0 to add commas, such as to show "6,000". In 99% of recent Wikipedia usage, there are relatively few articles using fractions (less than 1% of articles using Convert show fractions).
 * Usage:  &rarr;
 * &rarr;
 * &rarr;
 * &rarr;
 * &rarr; Expression error: Unexpected &lt; operator

Implementation
The check, for fraction parts, uses parser-function to split a number at "/" (if any, as in: 6+3/8) and then checks if part 2 (the denominator, after the slash) contains a number, to trigger use of Convert/numdisp/frac). Hence, the template uses:
 * #if:

That if-expression will be true if a denominator exists (such as "8" in 6+3/8).