default

What's the idiom in Ruby when you want to have a default argument to a function, but one that is dependent on another parameter / another variable? For example, in Python, an example is: def insort_right(a, x, lo=0, hi=None): if hi is None: hi = len(a) while lo < hi: mid = (lo+hi)//2 if x < a[mid]: hi = mid else: lo = mid+1 a.insert(lo, x) Here, if hi is not supplied, it should be len(a) . You can't do len(a) in the default argument list, so you assign it a sentinel value, None, and check for that. What would the equivalent be in Ruby? def foo(a, l = a.size) end 来源： https://stackoverflow.com

Consider this code: @Retention(RetentionPolicy.RUNTIME) @Target(ElementType.METHOD) public @interface Bar { Foo foo() default FooImpl.FooConstant; } Compiler error: annotation value not of an allowable type If I replace Foo with FooImpl the code is accepted. What's the reason for this behavior? If I replace Foo with FooImpl the code is accepted. I would be very surprised if this compiled, unless FooImpl is an enum. Annotation members may only contain the following: primitive type String Class literal annotation enum item or 1-dimensional arrays of any of the above It is a compile-time error if

Is there ANY difference between those two statements?: INSERT INTO distributors (did, dname) VALUES (DEFAULT, 'XYZ Widgets'); and: INSERT INTO distributors (dname) VALUES ('XYZ Widgets'); I mean is there at least one reason to use one or another pattern in some particular situation or is it completely the same? did is a serial column. It's exactly the same thing. No need to pick one instead of the other. Usually default keyword is handy when you have computer-generated code. It makes life easier to just use every single column in the insert clause and just use default when you don't have a

I have a JFrame with three JButtons on it. I have set txtSearch (a JTextField component) to have the focus when JFrame loads. One of the buttons is set as the default button. This is my code: private void formWindowOpened(java.awt.event.WindowEvent evt) { // btnRefresh.setMnemonic(KeyEvent.VK_R); // Even if this line // is not commented, but // still the event wouldn't fire. this.getRootPane().setDefaultButton(btnRefresh); } When it loads, the button is just selected, but it did nothing when the Enter key was being pressed. How do I correctly implement it? btnRefresh.addActionListener(new java

Open this link in IE to exactly understand the behavior that I will be describing and seek a hack for. I have the following select list: <select> <option value="volvo">Volvo</option> <option value="saab">Saab</option> <option value="mercedes">Mercedes</option> <option value="audi">Audi</option> </select> When I render this in IE, drop-down behavior of this changes compared to other browsers due to which some of the options are pushed above the selectbox while the others are pushed below (based on the selected option) Since this is the default behavior of IE , what I am looking for is that the

I am reading data from a source in the Data Flow tab. The data is put through a Conditional Split Order 1 -> ColA = "Y" Order 2 -> ColB = "Y" If the Default output condition gets hit, being neither ColA or ColB = "Y"... then I want to throw an exception / error so that it hits the "Fail Component" block. Pick your poison and connect it to the Default output. The quick and dirty is to attach a Derived Column Transformation and force a division by zero error. My preference is to route to a Script component. In the script component, I pass in the business keys of the rows as ReadOnly. For each