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Something to Try First (After Connecting)

You should start with loading the file you are working with. Do this with Loading Current File and Dependencies, ctrl+alt+c enter.

To get a feeling for evaluating code in the editor and get immediate response from the REPL try this:

  • On a new line, type a comment form and put some code inside it:
(comment
  (+ (* 2 2)
      2)
  (Math/abs -1)
  (hello "Calva REPL")
  (defn hello [s]
    (str "Hello " s))
  (range 10)
  "I ♥️ Clojure")

Then:

  1. Place the cursor behind the form (* 2 2) and issue the command Calva: Evaluate Current Form, ctrl+enter.
    • You should see the result being displayed inline. Press esc to dismiss it.
  2. Now issue the command Evaluate Current Top Level Form (defun), alt+enter.
    • You should see the whole form (+ (* 2 2) 2) getting highlighted and the result of that expression being displayed inline.
  3. Evaluate each form inside the comment form using the Top Level command.
    • You should see each one of them evaluated.
    • Evaluating the (hello "Calva REPL") form before the (defn hello... form should result in an error/exception. A stacktrace is then printed in the output window
    • Try it again after having evaluated the defnform.

Demo:

Comment top level form evaluation!

How does this work?

Calva has this notion about the current form. Issue the Evaluate Current Form command, with the cursor placed in different locations to get a feeling for how the current form is determined.

There is also a concept about the current top level form. Good for evaluating various defs defn, defthis, defthat. With your cursor placed anywhere inside such a form.

The Top Level command also works inside (comment ...) forms, treating the comment as creating a new top level context. It is good for in-file code experimentation.

See also