I am currently reading ANSI Common Lisp by Paul Graham, and I have a question about writing lambda expressions.

Do we need to prefix a lambda expression with #'?. If I write something like this in REPL, it will work fine

> ((lambda (x) (+ x 1)) 1)
  2

so will this

> (mapcar (lambda (x) (+ x x)) '(1 2 3 4))
  (2 4 6 8)

I understand that #' denotes a function. So my question is, is it some sort of convention or recommended practice? Can anything go wrong if I don't prefix lambdas with #', is it implementation dependent?

common-lisp lambda clisp
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