Hey... how would you validate a full_name field (name surname).
Instead of validating the characters that are there, you might just want to ensure some set of characters is not present.
class User < ActiveRecord::Base
validates_format_of :full_name, :with => /\A[^0-9`!@#\$%\^&*+_=]+\z/
# add any other characters you'd like to disallow inside the [ brackets ]
# metacharacters [, \, ^, $, ., |, ?, *, +, (, and ) need to be escaped with a \
end
Ms. Jan Levinson-Gould # pass
Dr. Martin Luther King, Jr. # pass
Brett d'Arras-d'Haudracey # pass
Brüno # pass
John Doe # pass
Mary-Jo Jane Sally Smith # pass
Fatty Mc.Error$ # fail
FA!L # fail
#arold Newm@n # fail
N4m3 w1th Numb3r5 # fail
NODE EXPLANATION
--------------------------------------------------------------------------------
\A the beginning of the string
--------------------------------------------------------------------------------
[^`!@#\$%\^&*+_=\d]+ any character except: '`', '!', '@', '#',
'\$', '%', '\^', '&', '*', '+', '_', '=',
digits (0-9) (1 or more times (matching
the most amount possible))
--------------------------------------------------------------------------------
\z the end of the string