Re: use of ? operator instead of if

2003-04-04 Thread R. Joseph Newton 
Jeff Westman wrote:

  At last! Thanks Bob, this /is/ how to use the conditional operator,
  while
 
  $VAL ? ( $VAL = $VAL:$expr ) : ( $VAL = $expr )
 
  /isn't/. ?: is an /operator/. It happens to have three operands
  instead of the usual two or 1, but it is meant for deriving a
  new value from three others, like a function.
 
  sub conditional {
  my ($test, $val1, $val2);
  return $val1 if $test;
  return $val2;
  }
 
  $VAL = conditional ($VAL, $VAL:$expr, $expr)
 
  Rob

 If you ask /me/ the above code is a lot harder to read to the simple one-line
 ternary as was mentioned before (expr:true?false).

Hi Jeff,

I certainly agree, and I'm sure Rob would too.  I don't hink his point was to
recommend the conditional() function for actual use, but to outline in function
form the logic implemented by the operator.

 The ternary operation is used to make your code more concise and readable,
 but in a limited context.  IE, you can nest ternary operations ... have fun
 maintaining it!

 -JW

Absolutely.  Terse operations can certainly add immediacy and punch to code when
the context is small enough to be crystal clear.  Trying to pack complicated
logic into them simply imposes an equal or greater burden of unpacking the logic
whe reviewing the code.

Joseph


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Re: use of ? operator instead of if

2003-04-03 Thread Rob Dixon 
Scott R. Godin wrote:
 Jeff Westman wrote:

  It's called the ternary operator, and works like this:
 
  $VAL ? $VAL = $VAL:$expr : $VAL = $expr;
 

 couldn't this be written as

 $VAL = $VAL ? $VAL:$expr : $expr;

Exactly Scott. See my post in this thread.

Rob




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use of ? operator instead of if

2003-04-01 Thread Ravi Malghan 
Hi: I have this statement which checks for existence
of the $VAL variable and performs certain actions

if($VAL){
  $VAL = $VAL:$expr; }
else { 
  $VAL = $expr; }

Can this 4 line statement be reduced to a single line
using ? operator?

Thanks
Ravi

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Re: use of ? operator instead of if

2003-04-01 Thread Jeff Westman 
It's called the ternary operator, and works like this:

$VAL ? $VAL = $VAL:$expr : $VAL = $expr;

IF_EXPR ? THEN_EXPR : ELSE_EXPR

Depending on context of how you are using it, I like to put the enter
statement in parens as in: ( ternary_statement )


-Jeff

--- Ravi Malghan [EMAIL PROTECTED] wrote:
 Hi: I have this statement which checks for existence
 of the $VAL variable and performs certain actions
 
 if($VAL){
   $VAL = $VAL:$expr; }
 else { 
   $VAL = $expr; }
 
 Can this 4 line statement be reduced to a single line
 using ? operator?
 
 Thanks
 Ravi
 
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RE: use of ? operator instead of if

2003-04-01 Thread Bob Showalter 
Ravi Malghan wrote:
 Hi: I have this statement which checks for existence
 of the $VAL variable and performs certain actions
 
 if($VAL){
   $VAL = $VAL:$expr; }
 else {
   $VAL = $expr; }
 
 Can this 4 line statement be reduced to a single line using ?
 operator? 

$VAL = $VAL ? $VAL:$expr : $expr;

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RE: use of ? operator instead of if

2003-04-01 Thread Balint, Jess 
Sure, something like the following:

$a = ( $b  1 ) ? b greater than 1 : b not greater than 1;

--jess

 -Original Message-
 From: Ravi Malghan [mailto:[EMAIL PROTECTED]
 Sent: Tuesday, April 01, 2003 12:45 PM
 To: [EMAIL PROTECTED]
 Subject: use of ? operator instead of if 
 
 
 Hi: I have this statement which checks for existence
 of the $VAL variable and performs certain actions
 
 if($VAL){
   $VAL = $VAL:$expr; }
 else { 
   $VAL = $expr; }
 
 Can this 4 line statement be reduced to a single line
 using ? operator?
 
 Thanks
 Ravi
 
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Re: use of ? operator instead of if

2003-04-01 Thread Rob Dixon 
Bob Showalter wrote:
 Ravi Malghan wrote:
  Hi: I have this statement which checks for existence
  of the $VAL variable and performs certain actions
 
  if($VAL){
$VAL = $VAL:$expr; }
  else {
$VAL = $expr; }
 
  Can this 4 line statement be reduced to a single line using ?
  operator?

 $VAL = $VAL ? $VAL:$expr : $expr;

At last! Thanks Bob, this /is/ how to use the conditional operator,
while

$VAL ? ( $VAL = $VAL:$expr ) : ( $VAL = $expr )

/isn't/. ?: is an /operator/. It happens to have three operands
instead of the usual two or 1, but it is meant for deriving a
new value from three others, like a function.

sub conditional {
my ($test, $val1, $val2);
return $val1 if $test;
return $val2;
}

$VAL = conditional ($VAL, $VAL:$expr, $expr)

Rob




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Re: use of ? operator instead of if

2003-04-01 Thread Jeff Westman 
--- Rob Dixon [EMAIL PROTECTED] wrote:
 Bob Showalter wrote:
  Ravi Malghan wrote:
   Hi: I have this statement which checks for existence
   of the $VAL variable and performs certain actions
  
   if($VAL){
 $VAL = $VAL:$expr; }
   else {
 $VAL = $expr; }
  
   Can this 4 line statement be reduced to a single line using ?
   operator?
 
  $VAL = $VAL ? $VAL:$expr : $expr;
 
 At last! Thanks Bob, this /is/ how to use the conditional operator,
 while
 
 $VAL ? ( $VAL = $VAL:$expr ) : ( $VAL = $expr )
 
 /isn't/. ?: is an /operator/. It happens to have three operands
 instead of the usual two or 1, but it is meant for deriving a
 new value from three others, like a function.
 
 sub conditional {
 my ($test, $val1, $val2);
 return $val1 if $test;
 return $val2;
 }
 
 $VAL = conditional ($VAL, $VAL:$expr, $expr)
 
 Rob


If you ask /me/ the above code is a lot harder to read to the simple one-line
ternary as was mentioned before (expr:true?false).

The ternary operation is used to make your code more concise and readable,
but in a limited context.  IE, you can nest ternary operations ... have fun
maintaining it! 

-JW

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