title: Build new operation function in R package
body: <p>I already read the tutorial about create the new package in R. I can use my custom function after clean and rebuild button in Rstudio. Now I want to create custom operation like <code>%&gt;%</code> in the <strong>magrittr</strong> pacakge, so I define the function blow in the <code>function.r</code>, I want my <code>+</code> function can paste two string like python.</p>
  
  <pre><code>`+` = function(x, y){
    if( is.character(x) &amp; is.character(y) ){
      return( paste0(x, y) )
    }else{
      `+` &lt;- base::`+`
      return( x + y )
    }
  }
  </code></pre>
  
  <p>When I clean and rebuild, I can not find this function in my package, also can not use this function.
  But it successful by using the <code>source("function.r")</code> to call the function.
  How do I create the operation function in my package like <strong>magrittr</strong> pacakge?</p>
  
  <p>Here is my package folder blow:
  <a href="https://drive.google.com/file/d/1Jse3qamEg_wsYLrZDd-nekGbqPMi8f76/view?usp=sharing" rel="nofollow noreferrer">https://drive.google.com/file/d/1Jse3qamEg_wsYLrZDd-nekGbqPMi8f76/view?usp=sharing</a></p>
  
  <p>Thanks.</p>