\centerline{\bf Hello World}
 \vskip .5cm
 This is a very simple example of the WEB system.
 
 @ First, we define a text to be displayed.
  
 @=
 'Hello, Literate Programming!'
 
 @ This is the mainprogram of the Pascal program.
 An expression surrounded by $\langle$ and $\rangle$
 is substituted by its definition.
 
 @p
 Program HelloWorld(output);
 begin
   @
 end.
 
 @ You can define an identifier after reference in WEB language.
 @=
 writeLn( @ )