shorthand syntax reference?

[=?iso-8859-1?B?dPZmZg==?=]

Usually I write something like ...

if (x==1) { doSomething() }

.... and that's how I see it in all the JS references I've found so
far.

But I have seen shorthand (?) for the same thing (?), like this ...

(x==1) ? doSomething()

.... and several other "alternate" methods.

Are they documented somewhere? I kinda like them, but are they
supported in the usual gang of browsers? or is it stupid to use them
because they are fringe/sloppy?

Thnx in advance :)

[Randy Webb]

töff said the following on 4/14/2007 11:06 PM:

Usually I write something like ...

if (x==1) { doSomething() }

... and that's how I see it in all the JS references I've found so
far.

But I have seen shorthand (?) for the same thing (?), like this ...

(x==1) ? doSomething()

... and several other "alternate" methods.

That is commonly called a "ternary expression" and your example is
missing the third part of it.

condition?true:false

Is the construct. If the condition is true then the true part gets
executed, if it is false then the false part gets executed.

Are they documented somewhere? I kinda like them, but are they
supported in the usual gang of browsers? or is it stupid to use them
because they are fringe/sloppy?

There is nothing stupid about the ternary operator.

--
Randy
Chance Favors The Prepared Mind
comp.lang.javascript FAQ - http://jibbering.com/faq/index.html
Javascript Best Practices - http://www.JavascriptToolbox.com/bestpractices/

[scripts.contact]

On Apr 14, 9:33 pm, Randy Webb <[e-mail]:

condition?true:false

Is the construct. If the condition is true then the true part gets
executed, if it is false then the false part gets executed.

condition?expression1:expression2

The operator _returns_ expression1 if the condition is true,
otherwise it returns expression2.

Are they documented somewhere?

http://msdn2.microsoft.com/en-us/library/be21c7hw.aspx

[Evertjan.]

scripts.contact wrote on 15 apr 2007 in comp.lang.javascript:

On Apr 14, 9:33 pm, Randy Webb <[e-mail]:

>condition?true:false

Is the construct. If the condition is true then the true part gets
executed, if it is false then the false part gets executed.

condition?expression1:expression2

The operator _returns_ expression1 if the condition is true,
otherwise it returns expression2.

True, but disregarding the use of,
or in absense of a result value,
it can be and often is used
simply to execute one of those expressions:
(a>27.3) ? alert('high') : alert('low');
--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

[Yorick]

"Evertjan." schreef

simply to execute one of those expressions:

(a>27.3) ? alert('high') : alert('low');

Simpler still, in this case, unless one of those
statements/expressions/values is likely to change from an alert to a confirm
or prompt or anything else, is of course:

alert( a>27.3 ? 'high' : 'low' );

hth
Yorick
http://www.yorick.onlyfools.com/

[Evertjan.]

Yorick wrote on 15 apr 2007 in comp.lang.javascript:

"Evertjan." schreef

>simply to execute one of those expressions:

(a>27.3) ? alert('high') : alert('low');

Simpler still, in this case, unless one of those
statements/expressions/values is likely to change from an alert to a
confirm or prompt or anything else, is of course:

alert( a>27.3 ? 'high' : 'low' );

Sure, but that was not the point.

The point was to show a tertiary choosing between functions without result.

Jammer dan.

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

[Ed Jay]

Evertjan. scribed:

>Yorick wrote on 15 apr 2007 in comp.lang.javascript:

>"Evertjan." schreef

>>simply to execute one of those expressions:

(a>27.3) ? alert('high') : alert('low');

Simpler still, in this case, unless one of those
statements/expressions/values is likely to change from an alert to a
confirm or prompt or anything else, is of course:

alert( a>27.3 ? 'high' : 'low' );

Sure, but that was not the point.

The point was to show a tertiary choosing between functions without result.

Jammer dan.

Is there a level of nested instructions, independent of easing code review,
that is recommended against? In your example above, 27.3 is the result of a
complex calculation, etc. Aside from reading ease, is there any reason one
should avoid lengthy, one-line, all-inclusive instructions, e.g., including
all the code that resulted in 27.3?
--
Ed Jay (remove 'M' to respond by email)

[Evertjan.]

Ed Jay wrote on 15 apr 2007 in comp.lang.javascript:

>>alert( a>27.3 ? 'high' : 'low' );

Sure, but that was not the point.

The point was to show a tertiary choosing between functions without
result.

Jammer dan.

Is there a level of nested instructions, independent of easing code
review, that is recommended against?

In general there is not, methinks, up to the amount of memory the
instruction stack takes or the time the instruction sequence takes before a
implemented timeout. Also a integer counter in your code, needed for
handling such deep nesting, or result variable, could overflow.

Try a reentrant faculty(n) code.

Specifically, as it is javascript we are discussing and not a specific
interperting engine, there could be implementation dependent limitations.

In your example above, 27.3 is
the result of a complex calculation, etc. Aside from reading ease, is
there any reason one should avoid lengthy, one-line, all-inclusive
instructions, e.g., including all the code that resulted in 27.3?

Next to reading ease, also debugging and error line reporing ease,
methinks.
--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

[Ed Jay]

Evertjan. scribed:

>Ed Jay wrote on 15 apr 2007 in comp.lang.javascript:

>>>alert( a>27.3 ? 'high' : 'low' );

Sure, but that was not the point.

The point was to show a tertiary choosing between functions without
result.

Jammer dan.

Is there a level of nested instructions, independent of easing code
review, that is recommended against?

In general there is not, methinks, up to the amount of memory the
instruction stack takes or the time the instruction sequence takes before a
implemented timeout. Also a integer counter in your code, needed for
handling such deep nesting, or result variable, could overflow.

Try a reentrant faculty(n) code.

Specifically, as it is javascript we are discussing and not a specific
interperting engine, there could be implementation dependent limitations.

>In your example above, 27.3 is
the result of a complex calculation, etc. Aside from reading ease, is
there any reason one should avoid lengthy, one-line, all-inclusive
instructions, e.g., including all the code that resulted in 27.3?

Next to reading ease, also debugging and error line reporing ease,
methinks.

Thanks.
--
Ed Jay (remove 'M' to respond by email)

[Dr J R Stockton]

In comp.lang.javascript message <11**********************@n76g2000hsh.go
oglegroups.com>, Sun, 15 Apr 2007 03:13:04, scripts.contact
<sc*************@gmail.composted:

>On Apr 14, 9:33 pm, Randy Webb <[e-mail]:

>condition?true:false

Is the construct. If the condition is true then the true part gets
executed, if it is false then the false part gets executed.

condition?expression1:expression2

The operator _returns_ expression1 if the condition is true,
otherwise it returns expression2.

Are they documented somewhere?

http://msdn2.microsoft.com/en-us/library/be21c7hw.aspx

That document describes Jscript, and includes "This page is specific to
..NET Framework 3.0".

That site is not therefore a reliable guide for those writing javascript
for the Web; for that, you want a site describing standards which all
browsers can be expected to aspire to agreeing with.

But in this case it is not misleading.

--
(c) John Stockton, Surrey, UK. REPLYyyww merlyn demon co uk Turnpike 6.05.
Web <URL:http://www.uwasa.fi/~ts/http/tsfaq.html-Timo Salmi: Usenet Q&A.
Web <URL:http://www.merlyn.demon.co.uk/news-use.htm: about usage of News.
No Encoding. Quotes precede replies. Snip well. Write clearly. Mail no News.

[Dr J R Stockton]

In comp.lang.javascript message <11**********************@o5g2000hsb.goo
glegroups.com>, Sat, 14 Apr 2007 20:06:37, töff <to**@arcticcoconut.com>
posted:

>
But I have seen shorthand (?) for the same thing (?), like this ...

(x==1) ? doSomething()

... and several other "alternate" methods.

Are they documented somewhere? I kinda like them, but are they
supported in the usual gang of browsers? or is it stupid to use them
because they are fringe/sloppy?

For such questions, you should look in ISO-16262, which should be linked
from the FAQ; failing that, try ECMA-262.

Such standards rarely contain the sentence-terminating question mark of
doubt as such, so a search for the character will be easy enough.

It's a good idea to read the newsgroup c.l.j 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.