[Query] Inspect Higher Order Functions

Generated from 'wiki-query.ts' on 2026-11-08, 09:20:49 UTC (v2.17.4), do not edit directly.

Determine whether functions are higher-order functions
This query is requested with the type inspect-higher-order.
Run in the REPL: :query @inspect-higher-order [(<crit>;...)] <code | file://path>

With this query you can identify which functions in the code are higher-order functions, i.e., either take a function as an argument or return a function. A parameter the body itself calls (function(g) g(), function(g) lapply(x, g)) counts as well, without any call site having to hand a function over. Please note, that functions that are just identities (e.g., function(x) x) are not considered higher-order if they do not take a function as an argument.

Using the example code f <- function() function(x) x; f() the following query returns the information for all identified function definitions whether they are higher-order functions:

[ { "type": "inspect-higher-order" } ]

(This can be shortened to @inspect-higher-order when used with the REPL command :query).

Results (prettified and summarized):

Query: inspect-higher-order
  - Function 5 (1.17-29) is not a higher-order function
  - Function 7 (1.6-29) is a higher-order function

{"inspect-higher-order":{".meta":{},"higherOrder":{"5":false,"7":true}},".meta":{}}

f <- function() function(x) x; f()

This query also supports a slicing criterion based query mode that only returns information for functions matching the given criteria:

[ { "type": "inspect-higher-order",   "filter": [ "1@function" ] } ]

(This can be shortened to @inspect-higher-order (1@function) "f <- function() function(x) x; f()" when used with the REPL command :query).

Results (prettified and summarized):

Query: inspect-higher-order
  - Function 7 (1.6-29) is a higher-order function

{"inspect-higher-order":{".meta":{},"higherOrder":{"7":true}},".meta":{}}