get_r_string | R Documentation |
STR_CONST
nodesConvert STR_CONST
text()
values into R strings. This is useful to account for arbitrary
character literals valid since R 4.0, e.g. R"------[hello]------"
, which is parsed in
R as "hello"
. It is quite cumbersome to write XPaths allowing for strings like this,
so whenever your linter logic requires testing a STR_CONST
node's value, use this
function.
NB: this is also properly vectorized on s
, and accepts a variety of inputs. Empty inputs
will become NA
outputs, which helps ensure that length(get_r_string(s)) == length(s)
.
get_r_string(s, xpath = NULL)
s |
An input string or strings. If |
xpath |
An XPath, passed on to |
tmp <- withr::local_tempfile(lines = "c('a', 'b')")
expr_as_xml <- get_source_expressions(tmp)$expressions[[1L]]$xml_parsed_content
writeLines(as.character(expr_as_xml))
get_r_string(expr_as_xml, "expr[2]") # "a"
get_r_string(expr_as_xml, "expr[3]") # "b"
# more importantly, extract strings under R>=4 raw strings
tmp4.0 <- withr::local_tempfile(lines = "c(R'(a\\b)', R'--[a\\\"\'\"\\b]--')")
expr_as_xml4.0 <- get_source_expressions(tmp4.0)$expressions[[1L]]$xml_parsed_content
writeLines(as.character(expr_as_xml4.0))
get_r_string(expr_as_xml4.0, "expr[2]") # "a\b"
get_r_string(expr_as_xml4.0, "expr[3]") # "a\\"'\"\b"
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