John-Li/my_programs — comment on commit 1935bbe2058b98c3abd8a8119a9199d7bb5ad94d
File: book/files/task_489.rb line 28
By gmile:

No worries, regexps are tricky. There are even some [books](http://www.amazon.com/s/ref=nb_sb_ss_c_1_18?url=search-alias%3Dstripbooks&field-keywords=regular+expressions&x=0&y=0&sprefix=regular+expression) related, which unveils the actual complexity of topic.