Inspector

The value inspector allows you to inspect and navigate the structure of data. While you can use it for pretty much anything (e.g. primitive data types, var, ref types) it’s most useful when you’re dealing with (deeply) nested collection-like data types (e.g. a vector of maps).

Usage

Typing C-c M-i (cider-inspect) after some form in a source buffer or the REPL will show you the structure of the form’s result in a new buffer. You can also use C-u C-c M-i to inspect the result of the current top-level form and C-u C-u C-c M-i to read an expression from the minibuffer and inspect its result.

Alternatively, after a regular eval command, you can inspect the last evaluated value using cider-inspect-last-result. When an inspector buffer is visible in the background, it is automatically updated with the last result. This behavior can be controlled with the variable cider-auto-inspect-after-eval.

The inspector can also be invoked in the middle of a debugging session, see here for more details.
The current value of the debugger can be sent as well to Clojure’s tap> facility. This can be used to integrate CIDER with various external tools which render tapped values in a web browser, for example.

You’ll have access to additional keybindings in the inspector buffer (which is internally using cider-inspector-mode). All bindings are listed at the bottom of the inspector buffer in the Keybindings section. It can be toggled by pressing ?.

Keyboard shortcut Command Description

Tab and Shift-Tab / n and p

cider-inspector-next-inspectable-object

Navigate inspectable sub-objects

Return

cider-inspector-operate-on-point

Inspect sub-objects

l

cider-inspector-pop

Pop to the parent object

g

cider-inspector-refresh

Refresh the inspector (e.g. if viewing an atom/ref/agent)

SPC or Next

cider-inspector-next-page

Jump to next page in paginated view

M-SPC or Prev

cider-inspector-prev-page

Jump to previous page in paginated view

y

cider-inspector-display-analytics

Calculate and display analytics for the inspected object. Analytics is supported for lists of numbers, strings, tuples, maps; for large key-value maps.

s

cider-inspector-set-page-size

Set a new page size in paginated view

c

cider-inspector-set-max-coll-size

Set a new maximum size above which nested collections are truncated

C

`cider-inspector-set-max-nested-depth

Set a new maximum nesting level above which the collections are truncated

a

cider-inspector-set-max-atom-length

Set a new maximum length above which nested atoms (non-collections) are truncated

v

cider-inspector-toggle-view-mode

Switch the rendering of the current value between :normal, :table, and :object view modes. In :table mode, render the value as a table (only supported for sequences of maps or tuples). In :object mode, any value is rendered as a plain Java object (by displaying its fields) instead of custom rendering rules that the Inspector applies in :normal mode.

P

cider-inspector-toggle-pretty-print

Toggle the pretty printing of values in the inspector. You can set the cider-inspector-pretty-print customization option to t, if you always want values to be pretty printed.

S

cider-inspector-toggle-sort-maps

Toggle the sorting of maps by key in the inspector. You can set the cider-inspector-sort-maps customization option to t if you always want maps to be displayed sorted.

D

cider-inspector-toggle-only-diff

When inspecting a diff result, toggle only displaying the differing values. You can set the cider-inspector-only-diff customization option to t if you always want to only show the diff instead of all values.

d

cider-inspector-def-current-val

Defines a var in the REPL namespace with current inspector value. If you tend to always choose the same name(s), you may want to set the cider-inspector-preferred-var-names customization option.

C-c C-p

cider-inspector-print-current-value

Print the current value of the inspector to the cider-result-buffer.

9

cider-inspector-previous-sibling

Navigates to the previous sibling, within a sequential collection.

0

cider-inspector-next-sibling

Navigates to the next sibling, within a sequential collection.

o

cider-inspector-open-thing-at-point

Opens the url or file at point, if found.

:

cider-inspect-expr-from-inspector

Prompts for a new value, rendering it in the Inspector.

t

cider-inspector-tap-current-val

Performs tap> using the inspector’s current value as its argument.

1

cider-inspector-tap-at-point

Performs tap> using the inspector’s current sub-value (the one at POINT) as its argument.

?

cider-inspector-toggle-display-help

Toggles the Keybindings help section at the bottom of the inspector buffer.

View modes

The point of the inspector is to display and navigate familiar data structures in a more pleasant and obvious way. For example, in the inspector, a sequential collection is rendered with each item on its own line and paginated. However, for some object types, inspector supports additional view modes. The modes can be cycled by calling cider-inspector-toggle-view-mode (v by default).

  • :object - default view mode for rendering any Java object that doesn’t have a custom renderer. Displays all object fields and their values. Known types can also be switched to this mode.

  • :table - can be enabled when inspecting a sequence of maps when each map has same or mostly same keys.

  • :hex - available for byte arrays and ByteBuffer objects, renders them in a "hexdump" style.

Configuration

You can see and change all variables related to Inspector by doing M-x customize-group cider-inspector.

You can set the amount of data shown by default with the variables cider-inspector-page-size, cider-inspector-max-coll-size, cider-inspector-max-nested-depth, and cider-inspector-max-atom-length. The values can be adjusted for the current inspector buffer using the keybindings listed in the table above.

When cider-inspector-tidy-qualified-keywords is enabled, namespace-qualified keyword like ::foo or ::alias/baz will be displayed in the same manner by the inspector if it was invoked in the code buffer of the same namespace or requires respective aliases.

Additional Resources