From 94591b88f34e6a8b591821c5cd281d138c0ac7ca Mon Sep 17 00:00:00 2001
From: Guillaume Leclerc <guillaume.leclerc@epfl.ch>
Date: Thu, 19 May 2016 16:44:56 +0200
Subject: [PATCH] add ensurers

---
 xonsh/environ.py |  4 ++--
 xonsh/tools.py   | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/xonsh/environ.py b/xonsh/environ.py
index 5a14fb342..6e2c395dc 100644
--- a/xonsh/environ.py
+++ b/xonsh/environ.py
@@ -26,7 +26,7 @@ from xonsh.tools import (
     is_completions_display_value, to_completions_display_value, is_string_set,
     csv_to_set, set_to_csv, get_sep, is_int, is_bool_seq, csv_to_bool_seq,
     bool_seq_to_csv, DefaultNotGiven, setup_win_unicode_console,
-    intensify_colors_on_win_setter
+    intensify_colors_on_win_setter, is_dynamic_cwd_width, to_dynamic_cwd_tuple, dynamic_cwd_tuple_to_str
 )
 from xonsh.codecache import run_script_with_cache
 from xonsh.dirstack import _get_cwd
@@ -85,7 +85,7 @@ DEFAULT_ENSURERS = {
     'PATHEXT': (is_env_path, str_to_env_path, env_path_to_str),
     'RAISE_SUBPROC_ERROR': (is_bool, to_bool, bool_to_str),
     'RIGHT_PROMPT': (is_string, ensure_string, ensure_string),
-    'DYNAMIC_CWD_WIDTH': (is_string, ensure_string, ensure_string),
+    'DYNAMIC_CWD_WIDTH': (is_dynamic_cwd_width, to_dynamic_cwd_tuple, dynamic_cwd_tuple_to_str),
     'TEEPTY_PIPE_DELAY': (is_float, float, str),
     'UPDATE_OS_ENVIRON': (is_bool, to_bool, bool_to_str),
     'XONSHRC': (is_env_path, str_to_env_path, env_path_to_str),
diff --git a/xonsh/tools.py b/xonsh/tools.py
index fdeee767d..97fe2c54b 100644
--- a/xonsh/tools.py
+++ b/xonsh/tools.py
@@ -736,6 +736,27 @@ def is_history_tuple(x):
     return False
 
 
+def is_dynamic_cwd_width(x):
+    if x[-1] == '%':
+        x = x[:-1]
+    return x.isdigit()
+
+
+def to_dynamic_cwd_tuple(x):
+    unit = 'c'
+    if x[-1] == '%':
+        x = x[:-1]
+        unit = '%'
+    return (float(x), unit)
+
+
+def dynamic_cwd_tuple_to_str(x):
+    if x[1] == '%':
+        return str(x[0]) + '%'
+    else:
+        return str(x[0])
+
+
 RE_HISTORY_TUPLE = re.compile('([-+]?[0-9]*\.?[0-9]+([eE][-+]?[0-9]+)?)\s*([A-Za-z]*)')
 
 def to_history_tuple(x):