title: Define function's argument in terminal by user in R
body: <p>I have a function with single argument</p>
  <pre><code>define &lt;- function(x) {...}
  </code></pre>
  <p>now I want to use readline function to let user define this argument itself in terminal
  I tried the following code but it does not work:</p>
  <pre><code>data &lt;- define(readline(prompt = &quot;Please enter Code: &quot;))
  </code></pre>