update doc

update os.path.isdir to handle windows path better

README.md

@@ -24,7 +24,6 @@ For example, `z foo bar` would match `/foo/bar` but not `/bar/foo`.
 - Interactive selection enables you to choose where to go before cd.
 - Intergrated with FZF (optional) for interactive selection and completion.
 - Quickly go back to a parent directory instead of typing "cd ../../..".
-- Cooperate with [fz](https://github.com/changyuheng/fz) to provide better completion, see [FAQ](https://github.com/skywind3000/z.lua/wiki/FAQ#fzsh-for-better-completion).
 - Corresponding experience in different shells and operating systems. 
 - Compatible with Lua 5.1, 5.2 and 5.3+
 - Self contained, distributed as a single `z.lua` script, no other dependence.
@@ -35,7 +34,7 @@ For example, `z foo bar` would match `/foo/bar` but not `/bar/foo`.
 ```bash
 z foo       # cd to most frecent dir matching foo
 z foo bar   # cd to most frecent dir matching foo and bar
-z -r foo    # cd to highest ranked dir matching foo
+z -r foo    # cd to the highest ranked dir matching foo
 z -t foo    # cd to most recently accessed dir matching foo
 z -l foo    # list matches instead of cd
 z -c foo    # restrict matches to subdirs of $PWD
@@ -220,14 +219,14 @@ If no match is found, it will fall back to default matching method.
 
 - Skip the current directory:
 
-  when you are calling `z xxx` but the best match is the current directory, z.lua will choose the 2nd best match result for you. Assuming the database:
+  When you are calling `z xxx` but the best match is the current directory, z.lua will choose the 2nd best match result for you. Assuming the database:
 
       10   /Users/Great_Wall/.rbenv/versions/2.4.1/lib/ruby/gems
       20   /Library/Ruby/Gems/2.0.0/gems
 
   When I use `z gems` by default, it will take me to `/Library/Ruby/Gems/2.0.0/gems`, but it's not what I want, so I press up arrow and execute `z gems` again, it will take me to `/Users/Great_Wall/.rbenv/versions/2.4.1/lib/ruby/gems` and this what I want.
 
-  Of course I can always use `z env gems` to indicate what I want precisely. Skip the current directory means when you use `z xxx` you always want to change directory instead of stay in the same directory and do nothing if current directory is the best match.
+  Of course, I can always use `z env gems` to indicate what I want precisely. Skip the current directory means when you use `z xxx` you always want to change directory instead of stay in the same directory and do nothing if current directory is the best match.
 
 The default matching method is designed to be compatible with original z.sh, but the enhanced matching method is much more handy and exclusive to z.lua.
 
@@ -236,7 +235,7 @@ The default matching method is designed to be compatible with original z.sh, but
 
 By default, z.lua will add current directory to database each time before display command prompt (correspond with z.sh). But there is an option to allow z.lua add path only if current working directory changed.
 
-To enable this, you can set `$_ZL_ADD_ONCE` to `1` before init z.lua. Or you can init z.lua on linux like this:
+To enable this, you can set `$_ZL_ADD_ONCE` to `1` before init z.lua. Or you can initialize z.lua on linux like this:
 
 ````bash
 eval "$(lua /path/to/z.lua --init bash once)"
@@ -286,7 +285,7 @@ NOTE: For fish shell, this feature requires fish 2.7.0 or above. You can specify
 New option `"-b"` can quickly go back to a specific parent directory in bash instead of typing "cd ../../.." redundantly.
 
 - **(No argument)**: `cd` into the project root, the project root the nearest parent directory with `.git`/`.hg`/`.svn` in it
-- **(One argument)**: `cd` into the closest parent starting with keyword, if not find, goto the parent containing keyword.
+- **(One argument)**: `cd` into the closest parent starting with keyword, if not find, go to the parent containing keyword.
 - **(Two arguments)**: replace the first value with the second one (in the current path).
 
 Let's start by aliasing `z -b` to `zb`:
@@ -419,7 +418,7 @@ Don't forget to read the [Frequently Asked Questions](https://github.com/skywind
 
 ## Benchmark
 
-The slowest part is adding path to history data file. It will run every time when you press enter (installed in $PROMPT_COMMAND). so I profile it on my nas:
+The slowest part is adding path to history data file. It will run every time when you press enter (installed in $PROMPT_COMMAND). So I profile it on my NAS:
 
 ```bash
 $ time autojump --add /tmp
@@ -457,6 +456,7 @@ As you see, z.lua is the fastest one and requires less resource.
 
 ## History
 
+- 1.5.4 (2019-02-19): fixed: file/path existence detection fails on read-only fs (closed [#49](https://github.com/skywind3000/z.lua/issues/49) by [@contrun](https://github.com/contrun)).
 - 1.5.3 (2019-02-17): new `$_ZL_FZF_FLAG` for passing additional flags to fzf, add `-e` argument to fzf.
 - 1.5.2 (2019-02-16): be aware of all arguments in fzf completion.
 - 1.5.1 (2019-02-15): new: simulated dir stack by `z -`, `z --` and `z -{num}`.

z.lua

@@ -4,7 +4,7 @@
 -- z.lua - a cd command that learns, by skywind 2018, 2019
 -- Licensed under MIT license.
 --
--- Version 1.5.3, Last Modified: 2019/02/17 16:22
+-- Version 1.5.4, Last Modified: 2019/02/19 11:18
 --
 -- * 10x faster than fasd and autojump, 3x faster than z.sh
 -- * available for posix shells: bash, zsh, sh, ash, dash, busybox
@@ -158,6 +158,10 @@ function string:startswith(text)
 	return false
 end
 
+function string:endswith(text)
+	return text == "" or self:sub(-#text) == text
+end
+
 function string:lstrip()
 	if self == nil then return nil end
 	local s = self:gsub('^%s+', '')
@@ -418,6 +422,8 @@ end
 function os.path.isdir(pathname)
 	if pathname == '/' then
 		return true
+	elseif pathname == '' then
+		return false
 	elseif windows then
 		if pathname == '\\' then
 			return true
@@ -425,15 +431,11 @@ function os.path.isdir(pathname)
 			return true
 		end
 	end
-	local name = pathname .. '/'
-	local ok, err, code = os.rename(name, name)
-	if not ok then
-		if code == 13 then
-			return true
-		end
-		return false
+	local name = pathname
+	if (not name:endswith('/')) and (not name:endswith('\\')) then
+		name = name .. '/'
 	end
-	return true
+	return os.path.exists(name)
 end
 
 
@@ -445,6 +447,12 @@ function os.path.exists(name)
 	if not ok then
 		if code == 13 then
 			return true
+		elseif code == 30 then
+			local f = io.open(name,"r")
+			if f ~= nil then
+				io.close(f)
+				return true
+			end
 		end
 		return false
 	end
@@ -1266,13 +1274,14 @@ function z_match(patterns, method, subdir)
 	subdir = subdir ~= nil and subdir or false
 	local M = data_load(DATA_FILE)
 	M = data_select(M, patterns, false)
+	M = data_filter(M)
 	if Z_MATCHNAME then
 		local N = data_select(M, patterns, true)
+		N = data_filter(N)
 		if #N > 0 then
 			M = N
 		end
 	end
-	M = data_filter(M)
 	M = data_update_frecent(M)
 	if method == 'time' then
 		current = os.time()
@@ -1325,7 +1334,7 @@ end
 -----------------------------------------------------------------------
 function z_print(M, weight, number)
 	local N = {}
-	local maxsize = 10
+	local maxsize = 9
 	local numsize = string.len(tostring(#M))
 	for _, item in pairs(M) do
 		local record = {}