title: Why does substitute change noquote text to a string in R?
body: <p>I wanted to answer a question regarding <code>plotmath</code> but I failed to get my desired <code>substitute</code> output.
  My desired output:<code>paste("Hi", paste(italic(yes),"why not?"))</code><br>
  and what I get: <code>paste("Hi", "paste(italic(yes),\"why not?\")")</code></p>
  
  <pre><code>text&lt;-'paste(italic(yes),"why not?")'
  text
  [1] "paste(italic(yes),\"why not?\")"
  noqoute_text&lt;-noquote(text)
  noqoute_text
  [1] paste(italic(yes),"why not?")
  sub&lt;-substitute(paste("Hi",noqoute_text),
             env=list(noqoute_text=noqoute_text))
  sub
  paste("Hi", "paste(italic(yes),\"why not?\")")
  </code></pre>