find_globals: Find global/local variables in R code

In xfun: Supporting Functions for Packages Maintained by 'Yihui Xie'

Find global/local variables in R code

Description

Use codetools::findGlobals() and codetools::findLocalsList() to find global and local variables in a piece of code. Global variables are defined outside the code, and local variables are created inside the code.

Usage

find_globals(code, envir = parent.frame())

find_locals(code)

Arguments

code	Either a character vector of R source code, or an R expression.
envir	The global environment in which global variables are to be found.

Value

A character vector of the variable names. If the source code contains syntax errors, an empty character vector will be returned.

Note

Due to the flexibility of creating and getting variables in R, these functions are not guaranteed to find all possible variables in the code (e.g., when the code is hidden behind eval()).

Examples

x = 2
xfun::find_globals("y = x + 1")
xfun::find_globals("y = get('x') + 1")  # x is not recognized
xfun::find_globals("y = zzz + 1")  # zzz doesn't exist

xfun::find_locals("y = x + 1")
xfun::find_locals("assign('y', x + 1)")  # it works
xfun::find_locals("assign('y', x + 1, new.env())")  # still smart
xfun::find_locals("eval(parse(text = 'y = x + 1'))")  # no way

xfun documentation built on April 3, 2025, 7:04 p.m.