This is an auxiliary template that allows one to encode "
||" (two pipes or vertical bars) within template parameters. If it is unnecessary to get a "
||", it is better to use "
||". However the "
||" delimiter for a wiki table has to be escaped by a template if it is used within a template.
There is usually no such problem with "
!!" (exclamation marks). This problem only affects "
||" (vertical bars) in conjunction with the m:Help:Parameter default mechanism within tables. However, in table rows starting with "
!" there can be problems with "
!!" being interpreted as a cell separator. Try replacing it with "
This template cannot be substituted.