The magic if clause that lets the same file serve as a library or a script: if __FILE__ == $0 # this library may be run as a standalone script end Packing and unpacking arrays: # put the first two words in a and b and the rest in arr a,b,*arr = *%w{a dog was … Read more
If you are accessing files, EAFP is more reliable than LBYL, because the operations involved in LBYL are not atomic, and the file system might change between the time you look and the time you leap. Actually, the standard name is TOCTOU – Time of Check, Time of Use; bugs caused by inaccurate checking are … Read more
Update: As mentioned by franta on the comments, if the method doSomething() returns null, then the code on the right side of the elvis operator will be executed, which might not be the desired case for most. But at the same time, in this case, it is very likely that the doSomething() method will only … Read more
My way (without additional branch) is: const auto separator = “WhatYouWantHere”; const auto* sep = “”; for(const auto& item : items) { std::cout << sep << item; sep = separator; }
A programming idiom is the usual way to code a task in a specific language. For example a loop is often written like this in C: for (i=0; i<10; i++) PHP will understand a similar construct: for ($i = 1; $i <= 10; $i++) But it is discouraged in PHP for looping over an array. … Read more
Instead of inducing performance overhead, why not use an extension method to alleviate both problems: public static void Raise(this EventHandler handler, object sender, EventArgs e) { if(handler != null) { handler(sender, e); } } Once defined, you never have to do another null event check again: // Works, even for null events. MyButtonClick.Raise(this, EventArgs.Empty);
Objects have a nil? method. if val.nil? || val == 0 [do something] end Or, for just one instruction: [do something] if val.nil? || val == 0
The best Java idiom I’ve seem for simulating keyword arguments in constructors is the Builder pattern, described in Effective Java 2nd Edition. The basic idea is to have a Builder class that has setters (but usually not getters) for the different constructor parameters. There’s also a build() method. The Builder class is often a (static) … Read more
I always go for the second method (using the GString template), though when there are more than a couple of parameters like you have, I tend to wrap them in ${X} as I find it makes it more readable. Running some benchmarks (using Nagai Masato‘s excellent GBench module) on these methods also shows templating is … Read more
Exceptions are not conditionals. The conditional version is clearer. That’s natural: this is straightforward flow control, which is what conditionals are designed for, not exceptions. The exception version is primarily used as an optimization when doing these lookups in a loop: for some algorithms it allows eliminating tests from inner loops. It doesn’t have that … Read more