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Why are functions in Ocaml/F# not recursive by default?
...uence in OCaml:
let shannon fold p =
let p x = p x *. log(p x) /. log 2.0 in
let p t x = t +. p x in
-. fold p 0.0
Note how the argument p to the higher-order shannon function is superceded by another p in the first line of the body and then another p in the second line of the body.
Conver...
JSON serialization of Google App Engine models
...h (JS "new Date()").
ms = time.mktime(value.utctimetuple()) * 1000
ms += getattr(value, 'microseconds', 0) / 1000
output[key] = int(ms)
elif isinstance(value, db.GeoPt):
output[key] = {'lat': value.lat, 'lon': value.lon}
elif isinstance...
Is there a performance difference between i++ and ++i in C?
...
406
Executive summary: No.
i++ could potentially be slower than ++i, since the old value of i
mig...
Check if a row exists, otherwise insert
... things can overbook a flight, as it will insert a new row when there are 10 tickets max and you are booking 20.
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static function in C
...t); /* prototype */
int f2(int); /* prototype */
int main(void) {
f1(10); /* ok, f1 is visible to the linker */
f2(12); /* nope, f2 is not visible to the linker */
return 0;
}
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Google Maps v3 - limit viewable area and zoom level
...script>
</head>
<body>
<div id="map" style="width: 400px; height: 300px;"></div>
<script type="text/javascript">
// This is the minimum zoom level that we'll allow
var minZoomLevel = 5;
var map = new google.maps.Map(document.getElementById('map'...
CMake not able to find OpenSSL library
...
I had the same problem (openssl) and this worked for me on Ubuntu 14.04.1 LTS. The solution is the same up to Ubuntu 18.04 (tested).
sudo apt-get install libssl-dev
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Sequelize Unknown column '*.createdAt' in 'field list'
...sequelize = new Sequelize('sequelize_test', 'root', null, {
host: "127.0.0.1",
dialect: 'mysql',
define: {
timestamps: false
}
});
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...
JavaScript for…in vs for
...which idiom is best understood.
An array is iterated using:
for (var i = 0; i < a.length; i++)
//do stuff with a[i]
An object being used as an associative array is iterated using:
for (var key in o)
//do stuff with o[key]
Unless you have earth shattering reasons, stick to the establis...
What exactly is a reentrant function?
...t, everything seems ok… But wait:
int main()
{
foo(bar);
return 0;
}
If the lock on mutex is not recursive, then here's what will happen, in the main thread:
main will call foo.
foo will acquire the lock.
foo will call bar, which will call foo.
the 2nd foo will try to acquire the lock...