expr_label

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Turn an expression to a label

expr_text() turns the expression into a single string, which might be multi-line. expr_name() is suitable for formatting names. It works best with symbols and scalar types, but also accepts calls. expr_label() formats the expression nicely for use in messages.

Usage
expr_label(expr)

expr_name(expr)

expr_text(expr, width = 60L, nlines = Inf)

Arguments
expr

An expression to labellise.

width

Width of each line.

nlines

Maximum number of lines to extract.

Aliases
  • expr_label
  • expr_name
  • expr_text
Examples
library(rlang) # NOT RUN { # To labellise a function argument, first capture it with # substitute(): fn <- function(x) expr_label(substitute(x)) fn(x:y) # Strings are encoded expr_label("a\nb") # Names and expressions are quoted with `` expr_label(quote(x)) expr_label(quote(a + b + c)) # Long expressions are collapsed expr_label(quote(foo({ 1 + 2 print(x) }))) # }
Documentation reproduced from package rlang, version 0.2.0, License: GPL-3

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