Le 02/10/14 à 13h32, "Julien RIVAUD (_FrnchFrgg_)" <[log in to unmask]> a écrit : > Le 02/10/2014 09:22, Ulrike Fischer a écrit : > >> Beside this there is also the timing problem Joseph mentioned: when >> should be tested if a key has been used? It is obviously not the key >> code of the key that can do it. So imho you are not looking for a >> .required property but a .enableifsettest property which adds and >> sets some boolean which you can later check. > > Or better yet, use an initial value for your property that unambiguously > represents "not set", and validate that at the beginning. > > Since you need to have an extra step to check if the required properties have > been set, you can as well use a token list to store the value instead of > directly an int for instance, and first check if it is your special "not set" > value, then cast it to integer yourself. Indeed. Maybe I was wrong, but it came to my mind that I wouldn't be the only one who needs such checks. And, instead of leaving each one hacking this by hands more or less properly, a general LaTeX3 frame could be useful. -- Denis