Perl can use a single scope in the same way as C language

Perl has a single scope that can be used in the same way as C. A single scope is not a scope that exists in combination with an if statement, for statement, or while statement, but a scope that can be defined independently and that can give a scope to a variable.

Perl's sole scope

Perl's sole scope.

{
  my $foo = 1;
}

C language independent scope

It is the sole scope of C language.

{
  int32_t foo = 1;
}

Comparison of Perl's single scope and C's single scope

Let's compare Perl's single scope with C's single scope. You can create a scope with the symbol "{}".

How to use a single scope

A single scope can declare valid variables only within that scope, so it is convenient to write as follows. It can also be nested.

{
  my $foo = 5;
  
  {
    my $foo = 1;
  }
  
  {
    my $foo = 2;
  }
  
  {
    my $foo = 3;
  }
}

In Perl, it's a reference-counted GC, so it also has the effect of freeing variables at the end of scope.

A single scope is very effective when writing exams. This is because the exam is the task of writing almost the same thing over and over, changing it little by little. It's very convenient to be able to write a new scope without defining a subroutine.

#Test 1
{
  my $baz = "abc";
  
  #Test 1 --Subtest 1
  {
    my $foo = 1;
    
    #Gonyo
    
    is ($foo, 5);
  }

  #Test 1 --Subtest 2
  {
    my $foo = 3;
    
    #Gonyo
    
    is ($foo, 10);
  }

  #Test 1 --Subtest 3
  {
    my $foo = 10;
    
    #Gonyo
    
    is ($foo, -5);
  }
}

#Test 2
{
  my $baz = "def";

  #Test 2 --Subtest 1
  {
    my $bar = 2;
    
    #Gonyo
    
    is ($bar, 3);
  }

  #Test 2 --Subtest 2
  {
    my $bar = 3;
    
    #Gonyo
    
    is ($bar, 45);
  }

  #Test 2 --Subtest 3
  {
    my $bar = 20;
    
    #Gonyo
    
    is ($bar, -19);
  }
}

Other similarities between Perl and C

In this article, I wrote that Perl's single scope is similar to C, but it also includes Perl's if statements, for statements, while statements, increments / decrements, operator priorities, scopes, and reference concepts. , Similar to the C language grammar.

Perl Philosophy