Add parser test for raw triple quoted string with backslash

Author: c42f

src/parser.jl

@@ -1601,7 +1601,8 @@ function parse_call_chain(ps::ParseState, mark, is_macrocall=false)
             # Triple quoted procesing for custom strings
             # r"""\nx""" ==> (macrocall @r_str "x")
             # r"""\n x\n y"""     ==> (macrocall @r_str (string-sr "x\n" "y"))
-
+            # r"""\n x\\n y"""    ==> (macrocall @r_str (string-sr "x\\\n" "y"))
+            #
             # Use a special token kind for string and cmd macro names so the
             # names can be expanded later as necessary.
             outk = is_string_delim(k) ? K"StringMacroName" : K"CmdMacroName"

test/parser.jl

@@ -301,8 +301,9 @@ tests = [
         "x\"\""      => """(macrocall @x_str "")"""
         "x``"        => """(macrocall @x_cmd "")"""
         # Triple quoted procesing for custom strings
-        "r\"\"\"\nx\"\"\""      => raw"""(macrocall @r_str "x")"""
-        "r\"\"\"\n x\n y\"\"\"" => raw"""(macrocall @r_str (string-sr "x\n" "y"))"""
+        "r\"\"\"\nx\"\"\""        => raw"""(macrocall @r_str "x")"""
+        "r\"\"\"\n x\n y\"\"\""   => raw"""(macrocall @r_str (string-sr "x\n" "y"))"""
+        "r\"\"\"\n x\\\n y\"\"\"" => raw"""(macrocall @r_str (string-sr "x\\\n" "y"))"""
         # Macro sufficies can include keywords and numbers
         "x\"s\"y"    => """(macrocall @x_str "s" "y")"""
         "x\"s\"end"  => """(macrocall @x_str "s" "end")"""