title: lambda expression of main function's return value
body: <p>In specific case, like this</p>
  
  <pre><code>f(x) { return x+5; } 
  g(x, y) { return 2*x + y; } 
  main() { return f(g(1, 2)); }
  </code></pre>
  
  <p>what is the lambda expression of return value of function main?</p>