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ANTLR: Is there a simple example?
...r, and evaluator using ANTLR4.
You first create a grammar. Below is a small grammar that you can use to evaluate expressions that are built using the 4 basic math operators: +, -, * and /. You can also group expressions using parenthesis.
Note that this grammar is just a very basic one: it does ...
Constructor overloading in Java - best practice
...onstructors as simple as possible, and the simplest way is that they only call this(...). That way you only need to check and handle the parameters once and only once.
public class Simple {
public Simple() {
this(null);
}
public Simple(Resource r) {
this(r, null);
...
PHP best way to MD5 multi-dimensional array?
...ll work.
md5(serialize($array));
However, it's worth noting that (ironically) json_encode performs noticeably faster:
md5(json_encode($array));
In fact, the speed increase is two-fold here as (1) json_encode alone performs faster than serialize, and (2) json_encode produces a smaller string an...
What exception classes are in the standard C++ library
...;exception> interface (debatable if you should catch this)
std::bad_alloc <new> failure to allocate storage
std::bad_array_new_length <new> invalid array length
std::bad_cast <typeinfo> execution of an invalid dynamic-cast
std::bad_exception <exception>...
C++ equivalent of StringBuffer/StringBuilder?
...f after profiling your code you discover this makes an improvement.
I normally use either std::string or std::stringstream. I have never had any problems with these. I would normally reserve some room first if I know the rough size of the string in advance.
I have seen other people make their ow...
MYSQL OR vs IN performance
...than using OR.
Do not believe people who give their "opinion", science is all about testing and evidence.
I ran a loop of 1000x the equivalent queries (for consistency, I used sql_no_cache):
IN: 2.34969592094s
OR: 5.83781504631s
Update:
(I don't have the source code for the original test, as it...
Add a “hook” to all AJAX requests on a page
...ttle investigating and this is what I came up with.
I'm not sure that it's all that useful as per the comments in the script and of course will only work for browsers using a native XMLHttpRequest object.
I think it will work if javascript libraries are in use as they will use the native object if p...
PowerShell: Store Entire Text File Contents in Variable
...
To get the entire contents of a file:
$content = [IO.File]::ReadAllText(".\test.txt")
Number of lines:
([IO.File]::ReadAllLines(".\test.txt")).length
or
(gc .\test.ps1).length
Sort of hackish to include trailing empty line:
[io.file]::ReadAllText(".\desktop\git-python\test.ps1")....
Fetch frame count with ffmpeg
...default=nokey=1:noprint_wrappers=1 input.mp4
This is a fast method.
Not all formats (such as Matroska) will report the number of frames resulting in the output of N/A. See the other methods listed below.
ffprobe: Count the number of frames
ffprobe -v error -count_frames -select_streams v:0 -sh...
Proper REST response for empty table?
Let's say you want to get list of users by calling GET to api/users , but currently the table was truncated so there are no users. What is the proper response for this scenario: 404 or 204 ?
...