Deparse a language object — deparse

This is an alternative to base::deparse() and rlang::expr_deparse() that handles additional corner cases and fails when encountering tokens other than symbols and syntactic literals where cited alternatives would produce non syntactic code.

Usage

deparse_call(
  call,
  one_liner = FALSE,
  pipe = FALSE,
  style = TRUE,
  collapse = !style,
  unicode_representation = c("ascii", "latin", "character", "unicode"),
  escape = FALSE
)

Arguments

call: A call
one_liner: Boolean. Whether to collapse multi-line expressions on a single line using semicolons
pipe: Boolean. Whether to use the base pipe to disentangle nested calls. This works best on simple calls.
style: Boolean. Whether to give a class "constructive_code" on the output for pretty printing.
collapse: Boolean. Whether to collapse the output to a single string, won't be directly visible if style is TRUE
unicode_representation: By default "ascii", which means only ASCII characters (code point < 128) will be used to construct strings and variable names. This makes sure that homoglyphs (different spaces and other identically displayed unicode characters) are printed differently, and avoid possible unfortunate copy and paste auto conversion issues. "latin" is more lax and uses all latin characters (code point < 256). "character" shows all characters, but not emojis. Finally "unicode" displays all characters and emojis, which is what dput() does.
escape: Whether to escape double quotes and backslashes. If FALSE we use single quotes to surround strings (including variable and element names) containing double quotes, and raw strings for strings that contain backslashes and/or a combination of single and double quotes. Depending on unicode_representation escape = FALSE cannot be applied on all strings.

Value

a string or a character vector, with a class "constructive_code" for pretty printing if style is TRUE

Examples

expr <- quote(foo(bar({this; that}, 1)))
deparse_call(expr)
#> foo(bar({
#>       this
#>       that
#>     }, 1))
deparse_call(expr, one_liner = TRUE)
#> foo(bar({this; that}, 1))
deparse_call(expr, pipe = TRUE)
#> {
#>   this
#>   that
#> } |> bar(1) |> foo()
deparse_call(expr, style = FALSE)
#> [1] "foo(bar({\n      this\n      that\n    }, 1))"
# some corner cases are handled better than in base R
deparse(call("$", 1, 1)) # returns non syntactic output
#> [1] "`$`(1, 1)"
deparse_call(call("$", 1, 1))
#> `$`(1, 1)