Fix parsing of equal assign in R 3.6.x (#6)

Equal assign r36 bug

NEWS.md

@@ -1,6 +1,11 @@
 
 # devel
 
+* Ensure that closing xml-tags for code expressions that end at the same
+  position in a file respect start-first-end-last ordering in the produced xml.
+  Ensures that the new `equal_assign` token in `getParseData()` for R-3.6 is
+  handled appropriately. #5 @russHyde
+
 # 1.0.2
 
 * Remove control characters `\003`, `\007`, `\010`, `\027`, as they are

R/package.R

@@ -107,7 +107,11 @@ xml_parse_data <- function(x, includeText = NA, pretty = FALSE) {
   }
 
   ## Order the nodes properly
-  pd <- pd[ order(pd$line1, pd$col1, -pd$line2, -pd$col2, pd$terminal), ]
+  ## - the terminal nodes from pd2 may be nested inside each other, when
+  ##   this happens they will have the same line1, col1, line2, col2 and
+  ##   terminal status; and 'start' is used to break ties
+  ord <- order(pd$line1, pd$col1, -pd$line2, -pd$col2, pd$terminal, -pd$start)
+  pd <- pd[ord, ]
 
   if (pretty) {
     str <- ! pd$terminal

tests/testthat/test.R

@@ -94,7 +94,6 @@ test_that("data frame input", {
 })
 
 
-
 test_that("Control-C character", {
   src <- "# Control-C \003
           # Bell  \007
@@ -105,3 +104,17 @@ test_that("Control-C character", {
   expect_is(x, "xml_document")
 })
 
+
+test_that("equal_assign is handled on R 3.6", {
+  # `a = 1` is an example of an R statement that gets parsed into nested xml
+  # nodes that have different token / tagnames (following the introduction of
+  # the `equal_assign` token to getParseData() in R-3.6), but the same ending
+  # position in the original code. Tokens/expressions that start before should
+  # end after any nested subexpressions in the resulting xml:
+
+  xml <- xml_parse_data(parse(text = "a = 1", keep.source = TRUE))
+  expect_true(is.character(xml))
+  expect_true(length(xml) == 1)
+  expect_silent(x <- xml2::read_xml(xml))
+})
+