Covariance and contravariance are qualities of the class not qualities of the parameters. (They are qualities that depend on the parameters, but they make statements about the class.) So, Function1[-A,+B] means that a function that takes superclasses of A can be viewed as a subclass of the original function. Let’s see this in practice: class … Read more
It can be solved by ticking javascript.suggest.completeFunctionCalls property up.
(gdb) rbreak file:. from http://sourceware.org/gdb/download/onlinedocs/gdb/Set-Breaks.html#Set-Breaks
I don’t think Swift supports static variable without having it attached to a class/struct. Try declaring a private struct with static variable. func foo() -> Int { struct Holder { static var timesCalled = 0 } Holder.timesCalled += 1 return Holder.timesCalled } 7> foo() $R0: Int = 1 8> foo() $R1: Int = 2 9> … Read more
Matlab expects functions to be in their own file. Copy the above code to a file ‘stat.m’ and it should work. This policy does cause an unnecessary number of short files, but it is required because of the way matlab handles variable scope. Each file gets its own scope, and all variables in the command … Read more
This is F#’s embarrassing skeleton in the closet. Try this: > let mapPair f (x,y) = (f x, f y) val mapPair : f:(‘a -> ‘b) -> x:’a * y:’a -> ‘b * ‘b Fully generic! Clearly, function application and tuples work. Now try this: > let makeList a b = [a;b] val makeList : … Read more
I’m also new to d3 and was struggling with the key function. I didn’t find Tristan Reid’s answer illuminating, because it doesn’t really talk much about the key function. Let’s work through an example, first without a key function, and then with. Here’s our initial html before applying javascript. We’ve got two divs, and there … Read more
Your function has a couple of smallint parameters. But in the call, you are using numeric literals that are presumed to be type integer. A string literal or string constant (‘123’) is not typed immediately. It remains type “unknown” until assigned or cast explicitly. However, a numeric literal or numeric constant is typed immediately. The … Read more
CodeIgniter’s Active Record methods automatically escape queries for you, to prevent sql injection. $this->db->select(‘*’)->from(‘tablename’)->where(‘var’, $val1); $this->db->get(); or $this->db->insert(‘tablename’, array(‘var1’=>$val1, ‘var2’=>$val2)); If you don’t want to use Active Records, you can use query bindings to prevent against injection. $sql=”SELECT * FROM tablename WHERE var = ?”; $this->db->query($sql, array($val1)); Or for inserting you can use the insert_string() … Read more