boolean opposites

[windandwaves]

Is there a way to write this simpler?
function makeOpposite(a) {
if(!a) {
a = true;
}
else {
a = false;
}
}

[Ian Collins]

windandwaves wrote:

Is there a way to write this simpler?
function makeOpposite(a) {
if(!a) {
a = true;
}
else {
a = false;
}
}

a = !a;

--
Ian Collins.

[windandwaves]

On Feb 15, 2:33 pm, Ian Collins <[e-mail]:

windandwaves wrote:

Is there a way to write this simpler?

function makeOpposite(a) {
if(!a) {
a = true;
}
else {
a = false;
}
}

a = !a;

--
Ian Collins.

awesome! Thanks Ian...

[John W. Kennedy]

windandwaves wrote:

On Feb 15, 2:33 pm, Ian Collins <[e-mail]:

>windandwaves wrote:

>>Is there a way to write this simpler?
function makeOpposite(a) {
if(!a) {
a = true;
}
else {
a = false;
}
}

a = !a;

Or:

a ^= true;

--
John W. Kennedy
"The blind rulers of Logres
Nourished the land on a fallacy of rational virtue."
-- Charles Williams. "Taliessin through Logres: Prelude"

[Evertjan.]

windandwaves wrote on 15 feb 2007 in comp.lang.javascript:

On Feb 15, 2:33 pm, Ian Collins <[e-mail]:

>windandwaves wrote:

Is there a way to write this simpler?

function makeOpposite(a) {
if(!a) {
a = true;
}
else {
a = false;
}
}

a = !a;

awesome! Thanks Ian...

function makeOpposite(a) {}

Since the OP's function does not return anything
and does not change a global variable,
an empty function is the "simplest".

=============================

However I surmize the OP would like this one:

function makeOpposite(a) {return !a;};

--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

[Richard Cornford]

On Feb 15, 4:22 am, John W. Kennedy wrote:
<snip>

>>a = !a;

Or:

a ^= true;

But then - a - is numeric not boolean.

Richard.

[Dr J R Stockton]

In comp.lang.javascript message <11*********************@m58g2000cwm.goo
glegroups.com>, Thu, 15 Feb 2007 02:40:40, Richard Cornford
<Ri*****@litotes.demon.co.ukposted:

>On Feb 15, 4:22 am, John W. Kennedy wrote:
<snip>

>>>a = !a;

Or:

a ^= true;

But then - a - is numeric not boolean.

Consequentially and more importantly, if the original a was an integer
greater than 1, then both a and the result would test as true.

It's a good idea to read the newsgroup and its FAQ. See below.

--
(c) John Stockton, Surrey, UK. ?@merlyn.demon.co.uk Turnpike v6.05 IE 6
news:comp.lang.javascript FAQ <URL:http://www.jibbering.com/faq/index.html>.
<URL:http://www.merlyn.demon.co.uk/js-index.htmjscr maths, dates, sources.
<URL:http://www.merlyn.demon.co.uk/TP/BP/Delphi/jscr/&c, FAQ items, links.

[Isaac Schlueter]

On Feb 15, 3:36 pm, Dr J R Stockton <[e-mail]>
wrote:

In comp.lang.javascript message <[e-mail]
glegroups.com>, Thu, 15 Feb 2007 02:40:40, Richard Cornford
<[e-mail]:

On Feb 15, 4:22 am, John W. Kennedy wrote:

a ^= true;

But then - a - is numeric not boolean.

Consequentially and more importantly, if the original a was an integer
greater than 1, then both a and the result would test as true.

Easy enough to fix! Just cast to boolean before and after.
a = !!(!!a ^ true);

Or my favorite js wtf, found in actual production code at a company
where I once worked:
x = (!!x ? !!true : !!false);
Apparently the author wanted to make really super duper certain he got
a boolean.

--i

[ron.h.hall]

On Feb 15, 6:09 pm, "Isaac Schlueter" <[e-mail]>
wrote:

On Feb 15, 3:36 pm, Dr J R Stockton <[e-mail]>
wrote:

In comp.lang.javascript message <[e-mail]
glegroups.com>, Thu, 15 Feb 2007 02:40:40, Richard Cornford
<[e-mail]:

>On Feb 15, 4:22 am, John W. Kennedy wrote:
> a ^= true;

>But then - a - is numeric not boolean.

Consequentially and more importantly, if the original a was an integer
greater than 1, then both a and the result would test as true.

Easy enough to fix! Just cast to boolean before and after.
a = !!(!!a ^ true);

Perhaps, but then because good coding practices demand code such as
this be readily readable and understood by others, advanced structure
would be required, e.g,

case a=!!(!!a ^ true) :-D ;

.../rh

[Dr J R Stockton]

In comp.lang.javascript message <11**********************@a34g2000cwb.go
oglegroups.com>, Thu, 15 Feb 2007 18:09:51, Isaac Schlueter
<is************@gmail.composted:

>
Or my favorite js wtf, found in actual production code at a company
where I once worked:
x = (!!x ? !!true : !!false);
Apparently the author wanted to make really super duper certain he got
a boolean.

That approach would not be safe in all languages. ISTR one in which
Boolean was nothing more than a predefined enumerated type in the
outermost scope, so that it would be possible to declare new variables
true and false and assign to them respectively 2>3 and 3>2.

--
(c) John Stockton, Surrey, UK. ?@merlyn.demon.co.uk DOS 3.3, 6.20 ; WinXP.
Web <URL:http://www.merlyn.demon.co.uk/- FAQqish topics, acronyms & links.
PAS EXE TXT ZIP via <URL:http://www.merlyn.demon.co.uk/programs/00index.htm>
My DOS <URL:http://www.merlyn.demon.co.uk/batfiles.htm- also batprogs.htm.

[Isaac Schlueter]

On Feb 16, 10:07 am, Dr J R Stockton <[e-mail]>
wrote:

That approach would not be safe in all languages. ISTR one in which
Boolean was nothing more than a predefined enumerated type in the
outermost scope, so that it would be possible to declare new variables
true and false and assign to them respectively 2>3 and 3>2.

Yeah, you're right. It's been a while since I worked with VB6, but I
remember being very very confused that (Not 3) yielded -2, which is
truish. It had something to do with the fact that Not in vb6 is
always bitwise. (Similarly, 3 + True = 2.)

--i