Add rawNamespace.

Fixes #385

NEWS.md

@@ -3,7 +3,8 @@
 * New tag `@rawRd` allows you to insert raw (unescaped) Rd code. `@evalRd()` is 
   similar, but instead of literal Rd, you give it R code that produces literal 
   Rd code when run. This should make it easier to experiment with new types of 
-  output (#385). 
+  output. `@rawNamespace` allows you to insert literal text in your namespace:
+  this can be useful for conditional imports (#385). 
 
 * `register.preref.parser()` and `register.preref.parsers()`  have been 
   deprecated - please use `register_tags()` instead.

R/parse-preref.R

@@ -88,7 +88,7 @@ parse.code <- function(x) {
     tag_warning(x, "requires a value")
   } else {
     tryCatch({
-      x$val <- parse(text = x$val)
+      parse(text = x$val)
       x
     }, error = function(e) {
       tag_warning(x, "code failed to parse.\n", e$message)

R/roclet-namespace.R

@@ -10,12 +10,13 @@ register_tags(
   importClassesFrom = words_parser(2),
   importFrom = words_parser(2),
   importMethodsFrom = words_parser(2),
+  rawNamespace = parse.code,
   S3method = words_parser(2, 2),
   useDynLib = words_parser(1)
 )
 
 ns_tags <- c('export', 'exportClass', 'exportMethod', 'exportPattern',
-  'S3method', 'import', 'importFrom', 'importClassesFrom',
+  'rawNamespace', 'S3method', 'import', 'importFrom', 'importClassesFrom',
   'importMethodsFrom', 'useDynLib')
 
 #' Roclet: make NAMESPACE.
@@ -121,6 +122,7 @@ ns_useDynLib         <- function(tag, part) {
     repeat_first("useDynLib", tag)
   }
 }
+ns_rawNamespace       <- function(tag, part) tag
 
 # Functions used by both default_export and ns_* functions
 export           <- function(x) one_per_line("export", x)

R/roclet-rd.R

@@ -115,7 +115,8 @@ block_to_rd <- function(block, base_path, env) {
   add_tag(rd, process_doc_type(block))
   add_tag(rd, process_tag(block, "rawRd"))
   add_tag(rd, process_tag(block, "evalRd", function(tag, param) {
-    out <- eval(param, envir = env)
+    expr <- parse(text = param)
+    out <- eval(expr, envir = env)
     new_tag("rawRd", as.character(out))
   }))
   add_tag(rd, process_tag(block, "title"))

tests/testthat/test-raw.R

@@ -30,3 +30,22 @@ test_that("rawRd inserted unchanged", {
   args <- get_tag(out, "rawRd")$values
   expect_equal(args, "20")
 })
+
+test_that("rawNamespace must be valid code", {
+  expect_warning(
+    roc_proc_text(namespace_roclet(), "
+      #' @rawNamespace if() {
+      #' @name a
+      NULL"),
+    "code failed to parse"
+  )
+})
+
+test_that("rawNamespace inserted unchanged", {
+  out <- roc_proc_text(namespace_roclet(), "
+    #' @rawNamespace xyz
+    #'   abc
+    NULL")
+
+  expect_equal(out, "xyz\n  abc")
+})