Template:Valid
Purpose
editDetermines whether something is valid in a certain context. Currently only implemented for determining if a number is within the precision that Wikipedia expressions can handle.
Returns
edittrue if the argument is valid, false if it is not.
Examples
edit{{valid|number=A}}= false (not a number){{valid|number=1234}}= true{{valid|number=+1234}}= true{{valid|number=-1234}}= true{{valid|number=(1234)}}= true (one pair of parenthesis is allowed){{valid|number=--1234}}= false (incorrect sign use){{valid|number=1234567890}}= true{{valid|number=12345678901234567890}}= false (too large){{valid|number=1.234567890}}= true{{valid|number=1.2345678901234567890}}= false (too many decimals)
Performance impact
editTemplate:Valid returns "true" for a valid, single number (2+2 gives "false"), and allows scientific notation (such as: -3.45E-07). The precision limit is determined live, for whichever server is formatting the page, typically allowing 14-digit precision (plus trailing zeroes), but it does not detect extreme precision problems dropping minor end-digits:
- cannot reject: -10020030040050000000000000000.70, treated as -1.002003004005E+28
The template has been written with minimal markup text, and could be used 50,000-13,000 times per page, or less when all 30-digit numbers. Template:Valid is typically used at upper levels of other templates, so it is unlikely to trigger expansion-depth problems. However, it has an expansion-depth of 8 levels, and returns "false" if used when nested too deep inside other templates, such as at level 33 when the expansion depth limit is 40.