respect shebangs

Author: lorenzwalthert

R/expr-is.R

@@ -29,6 +29,27 @@ is_function_dec <- function(pd) {
   pd$token[1] == "FUNCTION"
 }
 
+is_comment <- function(pd) {
+  if (is.null(pd)) return(FALSE)
+  pd$token == "COMMENT"
+}
+
+#' Identify comments that are shebangs
+#'
+#' Shebangs should be preserved and no space should be inserted between
+#' \# and !. A comment is a shebang if it is the first top level token
+#' (identified with `pos_id`) and if it starts with `#!`.
+#' @param pd A parse table.
+#' @examples
+#' style_text("#!/usr/bin/env Rscript")
+is_shebang <- function(pd) {
+  if (is.null(pd)) return(rep(FALSE, nrow(pd)))
+  is_first_comment <- is_comment(pd) & (pd$pos_id == 1L)
+  is_first_comment[is_first_comment] <- grepl(
+    "^#!", pd$text[is_first_comment], perl = TRUE
+  )
+  is_first_comment
+}
 
 contains_else_expr <- function(pd) {
   any(pd$token == "ELSE")

R/rules-spacing.R

@@ -181,14 +181,13 @@ set_space_between_levels <- function(pd_flat) {
 #'   after the regex "^#+'*".
 #' @importFrom purrr map_chr
 start_comments_with_space <- function(pd, force_one = FALSE) {
-  comment_pos <- pd$token == "COMMENT"
+  comment_pos <- is_comment(pd) & !is_shebang(pd)
   if (!any(comment_pos)) return(pd)
 
   comments <- rematch2::re_match(
     pd$text[comment_pos],
     "^(?<prefix>#+['\\*]*)(?<space_after_prefix> *)(?<text>.*)$"
   )
-
   comments$space_after_prefix <- nchar(
     comments$space_after_prefix, type = "width"
   )

man/is_shebang.Rd

@@ -0,0 +1,10 @@
+#A comment
+#!/usr/bin/env Rscript
+#!/usr/bin/env Rscript 
+a <- 3
+
+#!/usr/bin /env Rscript -m --set "W"
+dd <- 33
+#!/usr/bin\ /env Rscript -m --set "W"
+c()
+#!NEED TO REMOVE THIS

tests/testthat/parse_comments/shebang_1-in.R

@@ -0,0 +1,10 @@
+# A comment
+# !/usr/bin/env Rscript
+# !/usr/bin/env Rscript
+a <- 3
+
+# !/usr/bin /env Rscript -m --set "W"
+dd <- 33
+# !/usr/bin\ /env Rscript -m --set "W"
+c()
+# !NEED TO REMOVE THIS

tests/testthat/parse_comments/shebang_1-in_tree

@@ -0,0 +1,9 @@
+#!/usr/bin/env Rscript
+#!/usr/bin/env Rscript
+a <- 3
+
+#!/usr/bin /env Rscript -m --set "W"
+dd <- 33
+#!/usr/bin\ /env Rscript -m --set "W"
+c()
+#!NEED TO REMOVE THIS

tests/testthat/parse_comments/shebang_1-out.R

@@ -0,0 +1,9 @@
+#!/usr/bin/env Rscript
+# !/usr/bin/env Rscript
+a <- 3
+
+# !/usr/bin /env Rscript -m --set "W"
+dd <- 33
+# !/usr/bin\ /env Rscript -m --set "W"
+c()
+# !NEED TO REMOVE THIS

tests/testthat/parse_comments/shebang_2-in.R

@@ -41,3 +41,10 @@ test_that("rplumber tags / syntax is handled properly", {
                                  "rplumber",
                                  transformer = style_text), NA)
 })
+
+
+test_that("hashbangs are respected", {
+  expect_warning(test_collection("parse_comments",
+                                 "shebang",
+                                 transformer = style_text), NA)
+})