fmi/ruby-lectures — pull request #14 by angueln (2012-11-30 12:13:04+00:00)
Title: make two regexps more precise in lecture 10

The solution of the problem of nested car expression validation validates more than it should:
```ruby
[1] pry(main)> validator = /^(\(car \g<1>*\w*\))*$/
=> /^(\(car \g<1>*\w*\))*$/
[2] pry(main)> '(car (car (car (car list)SomeText)))'.match validator
=> #
#Alternatively,
[3] pry(main)> validator = /^(\(car (\g<1>*|\w*)\))*$/
=> /^(\(car (\g<1>*|\w*)\))*$/
[4] pry(main)> '(car (car (car (car list)SomeText)))'.match validator
=> nil
[5] pry(main)> '(car (car (car (car list))))'.match validator
=> #
```