CODEWITHSUNDEEP
perl
made_in_india
made_in_india

Reputation: 2279

perl expression meaning for statement $a &&= ;

Recently I came across this Perl expression on a blog, unable to grab it purpose.

    my $success = 1; 
    $success &&= $insert_handle->execute($first, $last, $department); 
    $success &&= $update_handle->execute($department);

Upvotes: 0

Views: 433

Answers (3)

ikegami
ikegami

Reputation: 385809

EXPR1 &&= EXPR2;

is short for 

EXPR1 = EXPR1 && EXPR2;

(Except that EXPR1 is only evaluated once.*)

The provided code

my $success = 1; 
$success &&= $insert_handle->execute($first, $last, $department); 
$success &&= $update_handle->execute($department);

could also have been written as:

my $success = 0;
if ($insert_handle->execute($first, $last, $department)) {
   if ($update_handle->execute($department)) {
      $success = 1;
   }
}

or

my $success = $insert_handle->execute($first, $last, $department)
           && $update_handle->execute($department);

* — This matters if EXPR1 has side-effects, which could very well happen if it's a magical variable or an lvalue sub.

my $x = 3;      # Prints:
print("$x\n");  # 3

sub x() :lvalue { print("x\n"); $x }

x &&= 4;        # x
print("$x\n");  # 4

x = x && 5;     # x x
print("$x\n");  # 5

Upvotes: 9

Michael Krelin - hacker
Michael Krelin - hacker

Reputation: 143091

It is a long way of saying.

 my $success =
     $insert_handle->execute($first, $last, $department)
     && $update_handle->execute($department);

Upvotes: 3

Rohit Jain
Rohit Jain

Reputation: 213253

Might be : - 

my $success = 1; 
$success = $success && $insert_handle->execute($first, $last, $department); 
$success = $success && $update_handle->execute($department);

Similar to : - 

a += b  
// is equivalent to
a = a + b

Upvotes: 1

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