November 2012
Intermediate to advanced
888 pages
54h 46m
Polish
Content preview from Ruby. Receptury
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17.1. Uruchamianie kodu wyłącznie w trybie debugowania
Problem
Chcemy wyświetlać komunikaty diagnostyczne lub uruchamiać kod sprawdzający poprawność danych, ale tylko w fazie projektowania, a nie podczas normalnej eksploatacji programu.
Rozwiązanie
Można uruchomić kod, ustawiwszy uprzednio wartość zmiennej globalnej $DEBUG na true. Tryb diagnostyczny można także włączyć poprzez przekazanie przełącznika --debug do interpretera języka Ruby.
Widoczny poniżej program wykonuje dzielenie dwóch liczb pseudolosowych. W programie tym kryje się prosty błąd, objawiający się sporadycznymi awariami. W kodzie programu dodano wiersz diagnostyczny, który ułatwia zaobserwowanie jego wewnętrznego działania:
#!/usr/bin/env ruby # divide.rb numerator ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.