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What optimizations can GHC be expected to perform reliably?
...hy are you worrying about it?)
Case expressions
Consider the following:
foo (0:_ ) = "zero"
foo (1:_ ) = "one"
foo (_:xs) = foo xs
foo ( []) = "end"
The first three equations all check whether the list is non-empty (among other things). But checking the same thing thrice is wasteful. Fortunate...
Why is there no logical xor in JavaScript?
...
there is... sort of:
if( foo ? !bar : bar ) {
...
}
or easier to read:
if( ( foo && !bar ) || ( !foo && bar ) ) {
...
}
why? dunno.
because javascript developers thought it would be unnecessary as it can be expressed by oth...
How to change the type of a field?
...omment below. Change the field bad from a number to a string in collection foo.
db.foo.find( { 'bad' : { $type : 1 } } ).forEach( function (x) {
x.bad = new String(x.bad); // convert field to string
db.foo.save(x);
});
...
How do I escape spaces in path for scp copy in Linux?
...
Also you can do something like:
scp foo@bar:"\"apath/with spaces in it/\""
The first level of quotes will be interpreted by scp and then the second level of quotes will preserve the spaces.
...
Add to Array jQuery
...his has nothing to do with jQuery though.
var myArray = [];
myArray.push("foo");
// myArray now contains "foo" at index 0.
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GCC dump preprocessor defines
...defined in your version of the
preprocessor. Assuming you have no
file foo.h, the command
touch foo.h; cpp -dM foo.h
will show all the predefined macros.
If you use -dM without the -E option,
-dM is interpreted as a synonym for -fdump-rtl-mach.
...
How to bind function arguments without binding this?
...l(this, ...boundArgs, ...args); };
};
Then, for a specified function foo and an object obj, the statement
return foo.call(obj, 1, 2, 3, 4);
is equivalent to
let bar = foo.bindArgs(1, 2);
return bar.call(obj, 3, 4);
where only the first and second arguments are bound to bar, while the con...
How to use arguments from previous command?
... Just a word of warning - if you use combined arguments like echo foo{,bar} baz, the command is recorded as printed and expands afterwards. With the above, using echo !:1 after resolves to echo foo{,bar} and then expands to echo foo foobar
– Sean
Jul 1...
Check existence of directory and create if doesn't exist
...exist")
# Handle this error as appropriate
}
Also be aware that if ~/foo doesn't exist then a call to dir.create('~/foo/bar') will fail unless you specify recursive = TRUE.
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Define global variable in a JavaScript function
...eclare a global variable:
<script>
var yourGlobalVariable;
function foo() {
// ...
}
</script>
Alternately, you can assign to a property on window:
<script>
function foo() {
window.yourGlobalVariable = ...;
}
</script>
...because in browsers, all global variable...