title: When exactly to use "assign" keyword and when to use "<=" operators?
body: <p>I'm learning verilog, I have read some tutorials but i'm a bit confused about this:</p>
  
  <p>When and why to use the "assign" keyword and when and why use the "&lt;=" operators. In what context? It is clear for me the difference between "&lt;=" and "=", being nonblocking and blocking, but beside that, some literature start by working with "assign" and others don't even use this keyword.</p>
  
  <p>Example:</p>
  
  <p>assign var_z = x|~y </p>
  
  <p>var_z &lt;= a + b</p>
  
  <p>Thank you.</p>