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What are the differences between concepts and template constraints?
...To quickly summarise their meanings:
Constraint - A predicate over statically evaluable properties of a type. Purely syntactic requirements. Not a domain abstraction.
Axioms - Semantic requirements of types that are assumed to be true. Not statically checked.
Concepts - General, abstract requireme...
Inheriting class methods from modules / mixins in Ruby
...ors of the class. You can look at the ancestors of any class or module by calling its ancestors method:
module M
def foo; "foo"; end
end
class C
include M
def bar; "bar"; end
end
C.ancestors
#=> [C, M, Object, Kernel, BasicObject]
# ^ look, it's right here!
When you call a metho...
What is the proper declaration of main?
...rn type, and what does it mean to return a value from main ? What are the allowed parameter types, and what are their meanings?
...
How to customize ?
...seinput">El Cucaratcha, for example</button>
<span id="selected_filename">No file selected</span>
<script>
$(document).ready( function() {
$('#falseinput').click(function(){
$("#fileinput").click();
});
});
$('#fileinput').change(function() {
$('#selected_filena...
Convert Object to JSON string
...
jQuery does only make some regexp checking before calling the native browser method window.JSON.parse(). If that is not available, it uses eval() or more exactly new Function() to create a Javascript object.
The opposite of JSON.parse() is JSON.stringify() which serializes a...
What is Prism for WPF?
I've come across something called Prism a lot recently. Microsoft, who run the project, describe it as
2 Answers
...
How is the java memory pool divided?
...ap memory
The heap memory is the runtime data area from which the Java VM allocates memory for all class instances and arrays. The heap may be of a fixed or variable size. The garbage collector is an automatic memory management system that reclaims heap memory for objects.
Eden Space: The pool fr...
How to check for file lock? [duplicate]
...ld become locked the very next second (read: short timespan).
Why specifically do you need to know if the file is locked anyway? Knowing that might give us some other way of giving you good advice.
If your code would look like this:
if not locked then
open and update file
Then between the t...
How to count the frequency of the elements in an unordered list?
...
@CristianCiupitu: sum(1 for _ in group).
– Martijn Pieters♦
Jul 29 '16 at 7:25
8
...
SQL - many-to-many table primary key
...at the table sorted, just the index. And the index won't be stored sequentially, it'll be stored in an efficient manner to be able to be retrieved quickly.
In addition, the vast majority of database tables are read far more often than written. That makes anything you do on the select side far more ...