Parse the text to detect doc comments and inlines properly in spin() (#…

…1605)

Fixes rstudio/rmarkdown#1444

R/spin.R

@@ -22,7 +22,7 @@
 #'   if you want to use \code{##} to denote documentation, you can use
 #'   \code{'^##\\\\s*'}.
 #' @param inline A regular expression to identify inline R expressions; by
-#'   default, code of the form \code{((code))} on its own line is treated as an
+#'   default, code of the form \code{\{\{code\}\}} on its own line is treated as an
 #'   inline expression.
 #' @param comment A pair of regular expressions for the start and end delimiters
 #'   of comments; the lines between a start and an end delimiter will be
@@ -64,11 +64,16 @@ spin = function(
   # remove comments
   if (length(c1)) x = x[-unique(unlist(mapply(seq, c1, c2, SIMPLIFY = FALSE)))]
 
+  # remove multiline string literals and symbols (note that this ignores lines with spaces at their
+  # beginnings, assuming doc and inline regex don't match these lines anyway)
+  parsed_data = getParseData(parse(text = x, keep.source = TRUE))
+  is_matchable = seq_along(x) %in% unique(parsed_data[parsed_data$col1 == 1, 'line1'])
+
   p = .fmt.pat[[tolower(format)]]
-  # turn ((expr)) into inline expressions, e.g. `r expr` or \Sexpr{expr}
-  if (any(i <- grepl(inline, x))) x[i] = gsub(inline, p[4], x[i])
+  # turn {{expr}} into inline expressions, e.g. `r expr` or \Sexpr{expr}
+  if (any(i <- is_matchable & grepl(inline, x))) x[i] = gsub(inline, p[4], x[i])
 
-  r = rle(grepl(doc, x) | i)  # inline expressions are treated as doc instead of code
+  r = rle((is_matchable & grepl(doc, x)) | i)  # inline expressions are treated as doc instead of code
   n = length(r$lengths); txt = vector('list', n); idx = c(0L, cumsum(r$lengths))
   p1 = gsub('\\{', '\\\\{', paste0('^', p[1L], '.*', p[2L], '$'))
 

tests/testit/test-spin.R

@@ -0,0 +1,26 @@
+library(testit)
+
+spin_w_tempfile = function(...) {
+  tmp = tempfile(fileext = ".R")
+  writeLines(c(...), tmp)
+  spinned = spin(tmp, knit = FALSE)
+  result = readLines(spinned)
+  file.remove(c(tmp, spinned))
+  result
+}
+
+assert(
+  'spin() detects lines for documentation',
+  identical(spin_w_tempfile("#' test", "1 * 1", "#' test"),
+            c("test", "", "```{r }", "1 * 1", "```", "", "test")),
+  # a multiline string literal contains the pattern of doc or inline
+  identical(spin_w_tempfile("code <- \"", "#' test\""),
+            c("", "```{r }", "code <- \"", "#' test\"", "```", "")),
+  identical(spin_w_tempfile("code <- \"", "{{ 1 + 1 }}", "\""),
+            c("", "```{r }", "code <- \"", "{{ 1 + 1 }}", "\"", "```", "")),
+  # a multiline symbol contains the pattern of doc or inline
+  identical(spin_w_tempfile("`", "#' test", "`"),
+            c("", "```{r }", "`", "#' test", "`", "```", "")),
+  identical(spin_w_tempfile("`", "{{ 1 + 1 }}", "`"),
+            c("", "```{r }", "`", "{{ 1 + 1 }}", "`", "```", ""))
+)