Inspect Clojure values

, d v is the Cider Inspector menu used to efficiently page through very large data sets and navigate through nested data structures.

, d v l shows the last evaluation in the inspector

, d v f evaluates the top level expression under the cursor and displays the result in the inspector

, d v e evaluates the previous expression before the cursor and displays the result in the inspector

Following evaluation results in Cider Inspector

Keep the Cider Inspector buffer open to update with the result of the latest expression evaluation, from , e or , d v menus.

Inspector in action

Clojure REPL workflow video includes using the Cider Inspector, 20 minutes into the video

Use Inspector buffer

Once Cider Inspector buffer is open:

n and p page through the data if the number of elements in the data set is greater than the page size (default 32), (cider-inspector-next-page, cider-inspector-prev-page)

TAB and S-TAB to navigate forward and backward through the elements that can be further inspected, (cider-inspector-next-inspectable-object, cider-inspector-previous-inspectable-object).

RET to inspect the current value under the cursor (cider-inspector-operate-on-point)

r to refresh the inspector view (cider-inspector-refresh)

s interactively sets the page size, updating how many elements are shown in one page of the cider inspector buffer, (cider-inspector-set-page-size).

q quits the cider inspector buffer

Inspecting simple values

Inspecting a dynamic var shows its value along with the datafy view

Inspect a system property shows

Inspecting Collections

Inspect a collection shows the underlying type, contents of that collection and index (where applicable). Only the elements are shown. The characters of the overall collection itself are not show, only the underlying type of collection (vector, map, lazy sequence, etc.).

If there are collections within collections then those values can be navigated too.

RET on an nested element in a collection will inspect that element in the same detail (cider-inspector-operate-on-point).

L to back to parent of a nested element (cider-inspector-pop).

Inspecting mutable values

Mutable containers, atom, ref, can also be inspected. The class of the container is shown, along with the class of the value it contains along with its elements.

Inspecting an atom or ref gives the value at the current time. The inspector does not update if the value of the atom or ref is updated. Use r in the inspector buffer to refresh or restart the inspector with , d v each time you want to check if the value has changed.

Inspecting Var meta data

Inspecting a var from a def expression shows meta information, the class type and summary of the value. Meta data can include the file and position of the code, the name of the var and which namespace it is defined in.

Inspecting a defn also shows the argument list as part of the meta data.

Open API docs data structure example shows class, value, meta information and datafy data