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Git equivalent of subversion's $URL$ keyword expansion

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I am considering migrating from subversion to git. One of the things we use subversion for our sysadmins to manage things like configuration files. To that end, we put $URL$ into each file, which expands to the file's location in the subversion tree. This lets the admins look at a file on some arbitrary host and figure out where in the tree it came from. The closest analog I could find is gitattributes. There is the filter= directive, but it seems that git doesn't communicate to the filter what filename it's filtering, which would be necessary to turn $URL$ into a path. There is also the ident

When should I use the new keyword in C++?

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问题 I\'ve been using C++ for a short while, and I\'ve been wondering about the new keyword. Simply, should I be using it, or not? 1) With the new keyword... MyClass* myClass = new MyClass(); myClass->MyField = \"Hello world!\"; 2) Without the new keyword... MyClass myClass; myClass.MyField = \"Hello world!\"; From an implementation perspective, they don\'t seem that different (but I\'m sure they are)... However, my primary language is C#, and of course the 1st method is what I\'m used to. The

Using the keyword “this” in java [duplicate]

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This question already has an answer here: When should I use “this” in a class? 17 answers I'm trying to get an understanding of what the the java keyword this actually does. I've been reading Sun's documentation but I'm still fuzzy on what this actually does. The this keyword is a reference to the current object. class Foo { private int bar; public Foo(int bar) { // the "this" keyword allows you to specify that // you mean "this type" and reference the members // of this type - in this instance it is allowing // you to disambiguate between the private member // "bar" and the parameter "bar"

What is the purpose of the var keyword and when should I use it (or omit it)?

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问题 NOTE : This question was asked from the viewpoint of ECMAScript version 3 or 5. The answers might become outdated with the introduction of new features in the release of ECMAScript 6. What exactly is the function of the var keyword in JavaScript, and what is the difference between var someNumber = 2; var someFunction = function() { doSomething; } var someObject = { } var someObject.someProperty = 5; and someNumber = 2; someFunction = function() { doSomething; } someObject = { } someObject

Normal arguments vs. keyword arguments

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问题 How are \"keyword arguments\" different from regular arguments? Can\'t all arguments be passed as name=value instead of using positional syntax? 回答1: there are two related concepts, both called "keyword arguments". On the calling side, which is what other commenters have mentioned, you have the ability to specify some function arguments by name. You have to mention them after all of the arguments without names (positional arguments), and there must be default values for any parameters which

What does 'synchronized' mean?

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问题 I have some questions regarding the usage and significance of the synchronized keyword. What is the significance of the synchronized keyword? When should methods be synchronized ? What does it mean programmatically and logically? 回答1: The synchronized keyword is all about different threads reading and writing to the same variables, objects and resources. This is not a trivial topic in Java, but here is a quote from Sun: synchronized methods enable a simple strategy for preventing thread

What is the volatile keyword useful for

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问题 At work today, I came across the volatile keyword in Java. Not being very familiar with it, I found this explanation: Java theory and practice: Managing volatility Given the detail in which that article explains the keyword in question, do you ever use it or could you ever see a case in which you could use this keyword in the correct manner? 回答1: volatile has semantics for memory visibility. Basically, the value of a volatile field becomes visible to all readers (other threads in particular)

Passing a dictionary to a function as keyword parameters

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I'd like to call a function in python using a dictionary. Here is some code: d = dict(param='test') def f(param): print(param) f(d) This prints {'param': 'test'} but I'd like it to just print test . I'd like it to work similarly for more parameters: d = dict(p1=1, p2=2) def f2(p1, p2): print(p1, p2) f2(d) Is this possible? Figured it out for myself in the end. It is simple, I was just missing the ** operator to unpack the dictionary So my example becomes: d = dict(p1=1, p2=2) def f2(p1,p2): print p1, p2 f2(**d) In[1]: def myfunc(a=1, b=2): In[2]: print(a, b) In[3]: mydict = {'a': 100, 'b': 200

“register” keyword in C?

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What does the register keyword do in C language? I have read that it is used for optimizing but is not clearly defined in any standard. Is it still relevant and if so, when would you use it? Brian Knoblauch It's a hint to the compiler that the variable will be heavily used and that you recommend it be kept in a processor register if possible. Most modern compilers do that automatically, and are better at picking them than us humans. qrdl I'm surprised that nobody mentioned that you cannot take an address of register variable, even if compiler decides to keep variable in memory rather than in