From c685de9803cbad4f1ba6d41b413726807e16d64a Mon Sep 17 00:00:00 2001
From: Gordon Ball <gordon@chronitis.net>
Date: Mon, 17 Oct 2016 15:17:05 +0200
Subject: [PATCH] Add support for path literals

---
 xonsh/built_ins.py    |  6 ++++++
 xonsh/parsers/base.py | 11 ++++++++---
 xonsh/tokenize.py     |  2 +-
 3 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/xonsh/built_ins.py b/xonsh/built_ins.py
index 39bd68735..79c98ef0e 100644
--- a/xonsh/built_ins.py
+++ b/xonsh/built_ins.py
@@ -14,6 +14,7 @@ import shlex
 import signal
 import atexit
 import inspect
+import pathlib
 import builtins
 import itertools
 import subprocess
@@ -138,6 +139,9 @@ def reglob(path, parts=None, i=None):
     return paths
 
 
+def path_literal(s):
+    return pathlib.Path(s)
+
 def regexsearch(s):
     s = expand_path(s)
     return reglob(s)
@@ -1124,6 +1128,7 @@ def load_builtins(execer=None, config=None, login=False, ctx=None):
     builtins.__xonsh_completers__ = xonsh.completers.init.default_completers()
     builtins.__xonsh_call_macro__ = call_macro
     builtins.__xonsh_enter_macro__ = enter_macro
+    builtins.__xonsh_path_literal__ = path_literal
     # public built-ins
     builtins.XonshError = XonshError
     builtins.XonshBlockError = XonshBlockError
@@ -1192,6 +1197,7 @@ def unload_builtins():
              '__xonsh_completers__',
              '__xonsh_call_macro__',
              '__xonsh_enter_macro__',
+             '__xonsh_path_literal__',
              'XonshError',
              'XonshBlockError',
              'XonshCalledProcessError',
diff --git a/xonsh/parsers/base.py b/xonsh/parsers/base.py
index d3180d383..265de58fc 100644
--- a/xonsh/parsers/base.py
+++ b/xonsh/parsers/base.py
@@ -1973,9 +1973,14 @@ class BaseParser(object):
     def p_string_literal(self, p):
         """string_literal : string_tok"""
         p1 = p[1]
-        s = ast.literal_eval(p1.value)
-        cls = ast.Bytes if p1.value.startswith('b') else ast.Str
-        p[0] = cls(s=s, lineno=p1.lineno, col_offset=p1.lexpos)
+        if p1.value.startswith('p'):
+            s = ast.literal_eval(p1.value[1:])
+            p[0] = xonsh_call('__xonsh_path_literal__', [s],
+                              lineno=p1.lineno, col=p1.lexpos)
+        else:
+            s = ast.literal_eval(p1.value)
+            cls = ast.Bytes if p1.value.startswith('b') else ast.Str
+            p[0] = cls(s=s, lineno=p1.lineno, col_offset=p1.lexpos)
 
     def p_string_literal_list(self, p):
         """string_literal_list : string_literal
diff --git a/xonsh/tokenize.py b/xonsh/tokenize.py
index 974e778f9..e70d0ea3c 100644
--- a/xonsh/tokenize.py
+++ b/xonsh/tokenize.py
@@ -205,7 +205,7 @@ Floatnumber = group(Pointfloat, Expfloat)
 Imagnumber = group(r'[0-9]+[jJ]', Floatnumber + r'[jJ]')
 Number = group(Imagnumber, Floatnumber, Intnumber)
 
-StringPrefix = r'(?:[bB][rR]?|[rR][bB]?|[uU])?'
+StringPrefix = r'(?:[bB][rR]?|[rR][bB]?|[uU]|[p])?'
 
 # Tail end of ' string.
 Single = r"[^'\\]*(?:\\.[^'\\]*)*'"