nrelsearch - See if a list contains a particular element
SYNOPSIS
package require nre ?2.0?nrelsearch ?mode? list pattern
DESCRIPTION
The nrelsearch command is just like the lsearch command
except that if the -regexp is used then the regular expression
package described in the nrematch man page is used.
Note that even though the -nocase switch is not supported
you can do case-insensitive matches by starting the regular
expression pattern with (?i).