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C++ static virtual members?

...ring getTypeInformation() { return getTypeInformationStatic(); } }; class Foo: public Object { public: static string getTypeInformationStatic() { return "derived class";} virtual string getTypeInformation() { return getTypeInformationStatic(); } }; What if base class has a great number of...
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Abort makefile if variable not set

...fined, ...) from inside the recipe Just move the check into the recipe: foo : @:$(call check_defined, BAR, baz value) The leading @ sign turns off command echoing and : is the actual command, a shell no-op stub. Showing target name The check_defined function can be improved to also outp...
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How to version control a record in a database

... Let's say you have a FOO table that admins and users can update. Most of the time you can write queries against the FOO table. Happy days. Then, I would create a FOO_HISTORY table. This has all the columns of the FOO table. The primary key i...
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What does map(&:name) mean in Ruby?

... It's shorthand for tags.map(&:name.to_proc).join(' ') If foo is an object with a to_proc method, then you can pass it to a method as &foo, which will call foo.to_proc and use that as the method's block. The Symbol#to_proc method was originally added by ActiveSupport but has be...
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Adding information to an exception?

... I'd do it like this so changing its type in foo() won't require also changing it in bar(). def foo(): try: raise IOError('Stuff') except: raise def bar(arg1): try: foo() except Exception as e: raise type(e)(e.message + ...
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Java 8: How do I work with exception throwing methods in streams?

...meException. A normal wrapping idiom is something like: private void safeFoo(final A a) { try { a.foo(); } catch (Exception ex) { throw new RuntimeException(ex); } } (Supertype exception Exception is only used as example, never try to catch it yourself) Then you can ...
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fs: how do I locate a parent folder?

... Try this: fs.readFile(__dirname + '/../../foo.bar'); Note the forward slash at the beginning of the relative path. share | improve this answer | ...
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Git: How to remove file from index without deleting files from any repository

...o the file, they will get conflicts. To resolve such conflicts, use git rm foo.conf && git rebase --continue (if the conflicting commit has changes besides those to the removed file) or git rebase --skip (if the conflicting commit has only changed to the removed file). Restore File as Untra...
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Is it possible to forward-declare a function in Python?

...st, but it's clean. You could create a recursion like the following: def foo(): bar() def bar(): foo() Python's functions are anonymous just like values are anonymous, yet they can be bound to a name. In the above code, foo() does not call a function with the name foo, it calls a funct...
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What's the difference between using “let” and “var”?

...sing block denoted by { } (hence the block scope). function run() { var foo = "Foo"; let bar = "Bar"; console.log(foo, bar); { let baz = "Bazz"; console.log(baz); } console.log(baz); // ReferenceError } run(); The reason why let keyword was introduced to the language was f...