====while statement====

Purpose: This command executes the statements defined within its body until the condition specified evaluates to true as soon as the condition evaluates to false looping stops. 

Status: Done.Nesting is not supported at the moment.

Syntax:

     while condition
     ...
     end

Let's see some examples of this command.

Example 1:
    
     param a=5
     while a>0
       echo a is :
       measure a eval(a-1)
     end

Output: 

      a is:
      a= 4.
      a is:
      a= 3.
      a is:
      a= 2.
      a is:
      a= 1.
      a is:
      a= 0.



Example 2:

    while 1
      echo I'll run infinite times.
    end

Output:
    gnucap> I'll run infinite times.
            I'll run infinite times.

and,this statement will execute infinite times!!