From 20c018fa27bce768d3d3724eb2a2561bee8e6bc3 Mon Sep 17 00:00:00 2001
From: Joseph Johansen <joe@stotles.com>
Date: Thu, 3 Dec 2020 00:07:48 +0000
Subject: [PATCH] Add support for escape sequences in double quoted rbs strings

---
 lib/rbs/parser.rb             | 20 +++++++++++++++++++-
 lib/rbs/parser.y              | 20 +++++++++++++++++++-
 test/rbs/type_parsing_test.rb | 10 ++++++++++
 test/rbs/types_test.rb        |  2 ++
 4 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/lib/rbs/parser.rb b/lib/rbs/parser.rb
index bae5a32c7..cc8f49da7 100644
--- a/lib/rbs/parser.rb
+++ b/lib/rbs/parser.rb
@@ -262,6 +262,10 @@ def empty_params_result
                              /%a\(.*?\)/,
                              /%a\<.*?\>/,
                              /%a\|.*?\|/)
+
+escape_sequences = %w[a b e f n r s t v "].map { |l| "\\\\#{l}" }
+DBL_QUOTE_STR_ESCAPE_SEQUENCES_RE = /(#{escape_sequences.join("|")})/
+
 def next_token
   if @type
     type = @type
@@ -341,7 +345,21 @@ def next_token
   when input.scan(/[a-z_]\w*\b/)
     new_token(:tLIDENT)
   when input.scan(/"(\\"|[^"])*"/)
-    s = input.matched.yield_self {|s| s[1, s.length - 2] }.gsub(/\\"/, '"')
+    s = input.matched.yield_self {|s| s[1, s.length - 2] }
+                     .gsub(DBL_QUOTE_STR_ESCAPE_SEQUENCES_RE) do |match|
+                       case match
+                       when '\\a' then "\a"
+                       when '\\b' then "\b"
+                       when '\\e' then "\e"
+                       when '\\f' then "\f"
+                       when '\\n' then "\n"
+                       when '\\r' then "\r"
+                       when '\\s' then "\s"
+                       when '\\t' then "\t"
+                       when '\\v' then "\v"
+                       when '\\"' then '"'
+                       end
+                     end
     new_token(:tSTRING, s)
   when input.scan(/'(\\'|[^'])*'/)
     s = input.matched.yield_self {|s| s[1, s.length - 2] }.gsub(/\\'/, "'")
diff --git a/lib/rbs/parser.y b/lib/rbs/parser.y
index 9d14c9814..6f6378574 100644
--- a/lib/rbs/parser.y
+++ b/lib/rbs/parser.y
@@ -1294,6 +1294,10 @@ ANNOTATION_RE = Regexp.union(/%a\{.*?\}/,
                              /%a\(.*?\)/,
                              /%a\<.*?\>/,
                              /%a\|.*?\|/)
+
+escape_sequences = %w[a b e f n r s t v "].map { |l| "\\\\#{l}" }
+DBL_QUOTE_STR_ESCAPE_SEQUENCES_RE = /(#{escape_sequences.join("|")})/
+
 def next_token
   if @type
     type = @type
@@ -1373,7 +1377,21 @@ def next_token
   when input.scan(/[a-z_]\w*\b/)
     new_token(:tLIDENT)
   when input.scan(/"(\\"|[^"])*"/)
-    s = input.matched.yield_self {|s| s[1, s.length - 2] }.gsub(/\\"/, '"')
+    s = input.matched.yield_self {|s| s[1, s.length - 2] }
+                     .gsub(DBL_QUOTE_STR_ESCAPE_SEQUENCES_RE) do |match|
+                       case match
+                       when '\\a' then "\a"
+                       when '\\b' then "\b"
+                       when '\\e' then "\e"
+                       when '\\f' then "\f"
+                       when '\\n' then "\n"
+                       when '\\r' then "\r"
+                       when '\\s' then "\s"
+                       when '\\t' then "\t"
+                       when '\\v' then "\v"
+                       when '\\"' then '"'
+                       end
+                     end
     new_token(:tSTRING, s)
   when input.scan(/'(\\'|[^'])*'/)
     s = input.matched.yield_self {|s| s[1, s.length - 2] }.gsub(/\\'/, "'")
diff --git a/test/rbs/type_parsing_test.rb b/test/rbs/type_parsing_test.rb
index 4bbd9a010..69237b693 100644
--- a/test/rbs/type_parsing_test.rb
+++ b/test/rbs/type_parsing_test.rb
@@ -536,6 +536,16 @@ def test_literal
       assert_instance_of Types::Literal, type
       assert_equal "super \" duper", type.literal
     end
+
+    Parser.parse_type('"escape sequences \a\b\e\f\n\r\s\t\v\""').yield_self do |type|
+      assert_instance_of Types::Literal, type
+      assert_equal "escape sequences \a\b\e\f\n\r\s\t\v\"", type.literal
+    end
+
+    Parser.parse_type(%q{'not escape sequences \a\b\e\f\n\r\s\t\v\"'}).yield_self do |type|
+      assert_instance_of Types::Literal, type
+      assert_equal 'not escape sequences \a\b\e\f\n\r\s\t\v\"', type.literal
+    end
   end
 
   def test_record
diff --git a/test/rbs/types_test.rb b/test/rbs/types_test.rb
index 7a35265de..f84d23f42 100644
--- a/test/rbs/types_test.rb
+++ b/test/rbs/types_test.rb
@@ -9,6 +9,8 @@ def test_to_s
     assert_equal "Array[Integer]", parse_type("Array[Integer]").to_s
     assert_equal "Array[Integer]?", parse_type("Array[Integer]?").to_s
     assert_equal '"foo"?', parse_type('"foo" ?').to_s
+    assert_equal '"foo\\\\n"', parse_type(%q{'foo\n'}).to_s
+    assert_equal '"foo\\n"', parse_type('"foo\n"').to_s
     assert_equal ":foo ?", parse_type(":foo ?").to_s
     assert_equal "[ Integer, bool? ]", parse_type("[Integer, bool?]").to_s
     assert_equal "[ ]", parse_type("[   ]").to_s