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What makes Lisp macros so special?
... nil)
;; loop from 0 upto and including 9
(loop for x in (range 10)
;; test for divisibility by two
if (= (mod x 2) 0)
;; append to the list
do (setq divisibleByTwo (append divisibleByTwo (list x))))
Before I go further, I should better explain what a macro is. It is a transformati...
CHECK constraint in MySQL is not working
...ple for BEFORE INSERT working after MySQL 5.5
DELIMITER $$
CREATE TRIGGER `test_before_insert` BEFORE INSERT ON `Test`
FOR EACH ROW
BEGIN
IF CHAR_LENGTH( NEW.ID ) < 4 THEN
SIGNAL SQLSTATE '12345'
SET MESSAGE_TEXT := 'check constraint on Test.ID failed';
END IF;
END$$ ...
How do I read / convert an InputStream into a String in Java?
... I found 11 main ways to do this (see below). And I wrote some performance tests (see results below):
Ways to convert an InputStream to a String:
Using IOUtils.toString (Apache Utils)
String result = IOUtils.toString(inputStream, StandardCharsets.UTF_8);
Using CharStreams (Guava)
String resu...
Rails: Check output of path helper from console
... Chubas' comment above worked in Rails 3. This is very useful when writing tests so I don't have to wait 1 minute to find out that the route is not correct. Also, it is great to test get and post calls. You don't need to call app.get first.
– B Seven
Aug 17 '11...
How to check whether a string is Base64 encoded or not
...ntation: commons.apache.org/proper/commons-codec/apidocs/org/apache/… : "Tests a given String to see if it contains only valid characters within the Base64 alphabet. Currently the method treats whitespace as valid." This means that this methods has some false positives like "whitespace" or numbers...
Fastest way to duplicate an array in JavaScript - slice vs. 'for' loop
...ays to clone an array:
loop
slice
Array.from()
concat
spread operator (FASTEST)
map A.map(function(e){return e;});
There has been a huuuge BENCHMARKS thread, providing following information:
for blink browsers slice() is the fastest method, concat() is a bit slower, and while loop is 2.4x slower....
How to catch curl errors in PHP
...TTP errors, the following provides a better approach:
function curl_error_test($url) {
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$responseBody = curl_exec($ch);
/*
* if curl_exec failed then
* $responseBody...
How to disable scrolling temporarily?
...adding event
var supportsPassive = false;
try {
window.addEventListener("test", null, Object.defineProperty({}, 'passive', {
get: function () { supportsPassive = true; }
}));
} catch(e) {}
var wheelOpt = supportsPassive ? { passive: false } : false;
var wheelEvent = 'onwheel' in document.c...
Get a filtered list of files in a directory
...ls.py
./apps/diaries/actions.py
./apps/diaries/querysets.py
./apps/library/tests/test_forms.py
./apps/library/migrations/0001_initial.py
./apps/polls/views.py
./apps/polls/formsets.py
./apps/polls/reports.py
./apps/polls/admin.py
Solution 3 - use "pathlib"
# lookup in current dir
path_ = pathlib....
How can I make my custom objects Parcelable?
... public void writeToParcel(Parcel dest, int flags) {
dest.writeStringArray(new String[] {this.id,
this.name,
this.grade});
}
public static final Parcelable.Creator CREATOR = new ...