Merge pull request #273 from Tieske/linter

added linter to the test setup and fixed warnings

42 files changed, 129 insertions, 122 deletions

diff --git a/.luacheckrc b/.luacheckrc
new file mode 100644
index 0000000..b549334
--- /dev/null
+++ b/.luacheckrc
@@ -0,0 +1,22 @@
+unused_args     = false
+redefined       = false
+max_line_length = false
+
+
+not_globals = {
+    "string.len",
+    "table.getn",
+}
+
+
+exclude_files = {
+    "tests/*.lua",
+    "tests/**/*.lua",
+    "here/*.lua",
+    "here/**/*.lua",
+
+    -- TODO: fix these files
+    "examples/symbols.lua",
+    "examples/test-symbols.lua",
+}
+
diff --git a/.travis.yml b/.travis.yml
index f0dd90f..8ebb248 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -14,12 +14,14 @@ before_install:
   - pip install hererocks
   - hererocks here -r^ --$LUA
   - source here/bin/activate
+  - luarocks install luacheck
 
 install:
   - luarocks make
   - luarocks install luacov-coveralls
 
 script:
+  - luacheck .
   - lua run.lua tests --luacov
 
 after_success:
diff --git a/examples/seesubst.lua b/examples/seesubst.lua
index e13a5fb..a2d0f18 100644
--- a/examples/seesubst.lua
+++ b/examples/seesubst.lua
@@ -4,10 +4,11 @@
 -- or 'pl.seq.map' (a function reference); these cases must be distinguished
 -- and a Markdown link generated pointing to the LuaDoc file.
 
-require 'pl'
+local sip = require 'pl.sip'
+local stringx = require 'pl.stringx'
 
 local res = {}
-s = [[
+local s = [[
 (@see pl.bonzo.dog)
 remember about @see pl.bonzo
 
@@ -15,7 +16,7 @@ remember about @see pl.bonzo
 
 local _gsub_patterns = {}
 
-function gsub (s,pat,subst,start)
+local function gsub (s,pat,subst,start)
     local fpat = _gsub_patterns[pat]
     if not fpat then
         -- use SIP to generate a proper string pattern.
diff --git a/examples/sipscan.lua b/examples/sipscan.lua
index 37f712e..78ac75b 100644
--- a/examples/sipscan.lua
+++ b/examples/sipscan.lua
@@ -3,9 +3,10 @@
 -- pattern generated:
 -- SYNC%s*%[([+%-%d]%d*)%]%s*([+%-%d]%d*)%s*([+%-%d]%d*)
 
-require 'pl'
+local sip = require 'pl.sip'
+local stringx = require 'pl.stringx'
 
-s = [[
+local s = [[
 SYNC [1] 0 547 (14679 sec)
 SYNC [2] 0 555 (14679 sec)
 SYNC [3] 0 563 (14679 sec)
@@ -16,7 +17,7 @@ SYNC [6] 0 587 (14679 sec)
 
 
 local first = true
-local start
+local expected
 local res = {}
 local pat = 'SYNC [$i{seq}] $i{diff} $i{val}'
 print(sip.create_pattern(pat))
diff --git a/examples/test-cmp.lua b/examples/test-cmp.lua
index e3748a3..cbab394 100644
--- a/examples/test-cmp.lua
+++ b/examples/test-cmp.lua
@@ -1,4 +1,3 @@
-A = require 'pl.tablex'
-ops = require 'pl.operator'
+local A = require 'pl.tablex'
 print(A.compare_no_order({1,2,3},{2,1,3}))
 print(A.compare_no_order({1,2,3},{2,1,3},'=='))
diff --git a/examples/test-listcallbacks.lua b/examples/test-listcallbacks.lua
index 6bcdad3..a9a31c3 100644
--- a/examples/test-listcallbacks.lua
+++ b/examples/test-listcallbacks.lua
@@ -1,7 +1,8 @@
 -- demonstrates how to use a list of callbacks
-require 'pl'
-actions = List()
-L = utils.string_lambda
+local List = require 'pl.List'
+local utils = require 'pl.utils'
+local actions = List()
+local L = utils.string_lambda
 
 actions:append(function() print 'hello' end)
 actions:append(L '|| print "yay"')
diff --git a/examples/test-pretty.lua b/examples/test-pretty.lua
index 1423c1c..7b2b553 100644
--- a/examples/test-pretty.lua
+++ b/examples/test-pretty.lua
@@ -1,6 +1,6 @@
 local pretty = require 'pl.pretty'
 
-tb = {
+local tb = {
     'one','two','three',{1,2,3},
     alpha=1,beta=2,gamma=3,['&']=true,[0]=false,
     _fred = {true,true},
diff --git a/examples/testapp.lua b/examples/testapp.lua
index 650ac4e..b0dbf5f 100644
--- a/examples/testapp.lua
+++ b/examples/testapp.lua
@@ -1,5 +1,5 @@
 -- shows how a script can get a private file path
 -- the output on my Windows machine is:
 -- C:\Documents and Settings\steve\.testapp\test.txt
-require 'pl'
+local app = require 'pl.app'
 print(app.appfile 'test.txt')
diff --git a/examples/testclone.lua b/examples/testclone.lua
index c211bc4..b0d948f 100644
--- a/examples/testclone.lua
+++ b/examples/testclone.lua
@@ -1,8 +1,10 @@
 --cloning a directory tree.
 local lfs = require 'lfs'
-require 'pl'
-p1 = [[examples]]
-p2 = [[copy/of/examples]]
+local path = require 'pl.path'
+local dir = require 'pl.dir'
+
+local p1 = [[examples]]
+local p2 = [[copy/of/examples]]
 
 if not path.isfile 'examples/testclone.lua' then
 	return print 'please run this in the penlight folder (below examples)'
@@ -14,7 +16,7 @@ dir.clonetree(p1,p2,dir.copyfile)
 assert(path.isdir 'copy')
 
 print '---'
-t = os.time()
+local t = os.time()
 print(lfs.touch('examples/testclone.lua',t,t+10))
 
 -- this should only update this file
diff --git a/examples/testconfig.lua b/examples/testconfig.lua
index 03349d6..4712747 100644
--- a/examples/testconfig.lua
+++ b/examples/testconfig.lua
@@ -1,7 +1,7 @@
 local stringio = require 'pl.stringio'
 local config = require 'pl.config'
 
-function dump(t,indent)
+local function dump(t,indent)
     if type(t) == 'table' then
         io.write(indent,'{\n')
         local newindent = indent..'  '
@@ -17,7 +17,7 @@ function dump(t,indent)
 end
 
 
-function testconfig(test)
+local function testconfig(test)
     local f = stringio.open(test)
     local c = config.read(f)
     f:close()
diff --git a/examples/testglobal.lua b/examples/testglobal.lua
index 053b6bf..0baaaef 100644
--- a/examples/testglobal.lua
+++ b/examples/testglobal.lua
@@ -15,7 +15,7 @@ local path = require 'pl.path'
 
 utils.on_error 'quit'
 
-local txt,err = file.read(arg[1] or path.normpath('examples/testglobal.lua'))
+local txt = file.read(arg[1] or path.normpath('examples/testglobal.lua'))
 local globals = List()
 for t,v in lexer.lua(txt) do
 	if t == 'iden' and rawget(_G,v) then
diff --git a/examples/testinputfields.lua b/examples/testinputfields.lua
index 37b3a8c..9269488 100644
--- a/examples/testinputfields.lua
+++ b/examples/testinputfields.lua
@@ -1,4 +1,4 @@
-require 'pl'
+local input = require 'pl.input'
 local sum = 0.0
 local count = 0
 local text = [[
diff --git a/examples/testinputfields2.lua b/examples/testinputfields2.lua
index fd7b0cd..fc649eb 100644
--- a/examples/testinputfields2.lua
+++ b/examples/testinputfields2.lua
@@ -1,4 +1,5 @@
-require 'pl'
+local input = require 'pl.input'
+local seq = require 'pl.seq'
 local text = [[
     981124001	2.0	18988.4	10047.1	4149.7
     981125001	0.8	19104.0	9970.4	5088.7
diff --git a/examples/testxml.lua b/examples/testxml.lua
index e7c7476..2528020 100644
--- a/examples/testxml.lua
+++ b/examples/testxml.lua
@@ -3,12 +3,13 @@
 -- This is (clearly) not a professional XML parser, so don't use it
 -- on your homework!
 
-require 'pl'
+local lexer = require 'pl.lexer'
+local pretty = require 'pl.pretty'
 
 local append = table.insert
 local skipws,expecting = lexer.skipws,lexer.expecting
 
-function parse_element (tok,tag)
+local function parse_element (tok,tag)
 	local tbl,t,v,attrib
 	tbl = {}
 	tbl.tag = tag  -- LOM 'tag' is the element tag
@@ -51,21 +52,22 @@ function parse_element (tok,tag)
 	end
 end
 
-function parse_xml (tok)
-    local t,v = skipws(tok)
+local function parse_xml (tok)
+	local t = skipws(tok)
+	local v
 	while t == '<' do
 		t,v = tok()
 		if t == '?' or t == '!' then
 			-- skip meta stuff and commentary
 			repeat t = tok() until t == '>'
-			t,v = expecting(tok,'<')
+			t = expecting(tok,'<')
 		else
 			return parse_element(tok,v)
 		end
 	end
 end
 
-s = [[
+local s = [[
 <?xml version="1.0" encoding="UTF-8"?>
 <sensor name="closure-meter-2" id="7D7D0600006F0D00" loc="100,100,0" device="closure-meter" init="true">
 <detector name="closure-meter" phenomenon="closure" units="mm" id="1"
diff --git a/examples/which.lua b/examples/which.lua
index 37f7649..0544cfc 100644
--- a/examples/which.lua
+++ b/examples/which.lua
@@ -7,7 +7,7 @@ local app = require 'pl.app'
 
 local pathl = List.split(os.getenv 'PATH',path.dirsep)
 
-function which (file)
+local function which (file)
     local res = pathl:map(path.join,file)
     res = res:filter(path.exists)
     if res then return res[1] end
diff --git a/lua/pl/Date.lua b/lua/pl/Date.lua
index 44c4b54..9c878d6 100644
--- a/lua/pl/Date.lua
+++ b/lua/pl/Date.lua
@@ -510,7 +510,7 @@ Allowed patterns:
 
 ]]
 
-local function looks_like_a_month(w) 
+local function looks_like_a_month(w)
     return w:match '^%a+,*$' ~= nil
 end
 local is_number = stringx.isdigit
@@ -537,7 +537,7 @@ local function  parse_iso_end(p,ns,sec)
     -- (we're working with the date as lower case, hence 'z')
     if p:match 'z$' then -- we're UTC!
         return  sec, {h=0,m=0}
-    end 
+    end
     p = p:gsub(':','') -- turn 00:30 to 0030
     local _,_,sign,offs = p:find('^([%+%-])(%d+)')
     if not sign then return sec, nil end -- not UTC
diff --git a/lua/pl/List.lua b/lua/pl/List.lua
index e19e702..b66c251 100644
--- a/lua/pl/List.lua
+++ b/lua/pl/List.lua
@@ -346,7 +346,7 @@ function List:__eq(L)
     return true
 end
 
---- Join the elements of a list using a delimiter. 
+--- Join the elements of a list using a delimiter.
 -- This method uses tostring on all elements.
 -- @string[opt=''] delim a delimiter string, can be empty.
 -- @return a string
diff --git a/lua/pl/OrderedMap.lua b/lua/pl/OrderedMap.lua
index 3e49af5..379c44f 100644
--- a/lua/pl/OrderedMap.lua
+++ b/lua/pl/OrderedMap.lua
@@ -32,7 +32,7 @@ end
 local assert_arg,raise = utils.assert_arg,utils.raise
 
 --- update an OrderedMap using a table.
--- If the table is itself an OrderedMap, then its entries will be appended. 
+-- If the table is itself an OrderedMap, then its entries will be appended.
 -- if it s a table of the form `{{key1=val1},{key2=val2},...}` these will be appended.
 --
 -- Otherwise, it is assumed to be a map-like table, and order of extra entries is arbitrary.
@@ -132,7 +132,7 @@ end
 function OrderedMap:iter ()
     local i = 0
     local keys = self._keys
-    local n,idx = #keys
+    local idx
     return function()
         i = i + 1
         if i > #keys then return nil end
diff --git a/lua/pl/app.lua b/lua/pl/app.lua
index 21b6a7b..bf9621b 100644
--- a/lua/pl/app.lua
+++ b/lua/pl/app.lua
@@ -50,7 +50,7 @@ end
 -- @return 'cannot create' error
 function app.appfile (file)
     local sname = path.basename(check_script_name())
-    local name,ext = path.splitext(sname)
+    local name = path.splitext(sname)
     local dir = path.join(path.expanduser('~'),'.'..name)
     if not path.isdir(dir) then
         local ret = path.mkdir(dir)
diff --git a/lua/pl/array2d.lua b/lua/pl/array2d.lua
index b15e39e..40b4eca 100644
--- a/lua/pl/array2d.lua
+++ b/lua/pl/array2d.lua
@@ -4,8 +4,8 @@
 -- Dependencies: `pl.utils`, `pl.tablex`, `pl.types`
 -- @module pl.array2d
 
-local type,tonumber,assert,tostring,io,ipairs,string,table =
-    _G.type,_G.tonumber,_G.assert,_G.tostring,_G.io,_G.ipairs,_G.string,_G.table
+local tonumber,assert,tostring,io,ipairs,string,table =
+    _G.tonumber,_G.assert,_G.tostring,_G.io,_G.ipairs,_G.string,_G.table
 local setmetatable,getmetatable = setmetatable,getmetatable
 
 local tablex = require 'pl.tablex'
@@ -16,6 +16,8 @@ local remove = table.remove
 local splitv,fprintf,assert_arg = utils.splitv,utils.fprintf,utils.assert_arg
 local byte = string.byte
 local stdout = io.stdout
+local min = math.min
+
 
 local array2d = {}
 
@@ -96,10 +98,6 @@ function array2d.reduce2 (opc,opr,a)
     return reduce(opc,tmp)
 end
 
-local function dimension (t)
-    return type(t[1])=='table' and 2 or 1
-end
-
 --- map a function over two arrays.
 -- They can be both or either 2D arrays
 -- @func f function of at least two arguments
@@ -253,8 +251,6 @@ function array2d.remove_col (t,j)
     end
 end
 
-local Ai = byte 'A'
-
 local function _parse (s)
     local c,r
     if s:sub(1,1) == 'R' then
@@ -401,8 +397,6 @@ function array2d.forall (t,row_op,end_row_op,i1,j1,i2,j2)
     end
 end
 
-local min, max = math.min, math.max
-
 ---- move a block from the destination to the source.
 -- @array2d dest a 2D array
 -- @int di start row in dest
@@ -440,7 +434,7 @@ function array2d.iter (a,indices,i1,j1,i2,j2)
     assert_arg(1,a,'table')
     local norowset = not (i2 and j2)
     i1,j1,i2,j2 = default_range(a,i1,j1,i2,j2)
-    local n,i,j = i2-i1+1,i1-1,j1-1
+    local i,j = i1-1,j1-1
     local row,nr = nil,0
     local onr = j2 - j1 + 1
     return function()
diff --git a/lua/pl/class.lua b/lua/pl/class.lua
index a57ac71..847f442 100644
--- a/lua/pl/class.lua
+++ b/lua/pl/class.lua
@@ -60,7 +60,7 @@ end
 -- if pussycat:is_a(Cat) then
 --   -- it's true, it is a Lion, but also a Cat
 -- end
--- 
+--
 -- if pussycat:is_a() == Lion then
 --   -- It's true
 -- end
@@ -131,7 +131,7 @@ local function _class(base,c_arg,c)
     else
         c = c or {}
     end
-   
+
     if type(base) == 'table' then
         -- our new class is a shallow copy of the base class!
         -- but be careful not to wipe out any methods we have been given at this point!
diff --git a/lua/pl/compat.lua b/lua/pl/compat.lua
index 58cf6b2..f3832b8 100644
--- a/lua/pl/compat.lua
+++ b/lua/pl/compat.lua
@@ -131,7 +131,7 @@ end
 -- @return the length
 -- @function table.pack
 if not table.pack then
-    function table.pack (...)
+    function table.pack (...)       -- luacheck: ignore
         return {n=select('#',...); ...}
     end
 end
@@ -144,7 +144,7 @@ end
 -- @function package.searchpath
 if not package.searchpath then
     local sep = package.config:sub(1,1)
-    function package.searchpath (mod,path)
+    function package.searchpath (mod,path)    -- luacheck: ignore
         mod = mod:gsub('%.',sep)
         for m in path:gmatch('[^;]+') do
             local nm = m:gsub('?',mod)
diff --git a/lua/pl/comprehension.lua b/lua/pl/comprehension.lua
index 9d8aa59..39be7c5 100644
--- a/lua/pl/comprehension.lua
+++ b/lua/pl/comprehension.lua
@@ -73,7 +73,6 @@ local ops = {
 -- @usage  "(x+y)^2 for x for y if x > y"  -- nested
 --
 local function parse_comprehension(expr)
-  local t = {}
   local pos = 1
 
   -- extract opname (if exists)
diff --git a/lua/pl/config.lua b/lua/pl/config.lua
index a71c472..b23c07b 100644
--- a/lua/pl/config.lua
+++ b/lua/pl/config.lua
@@ -103,7 +103,7 @@ end
 -- @return a table containing items, or `nil`
 -- @return error message (same as @{config.lines}
 function config.read(file,cnfg)
-    local f,openf,err,auto
+    local auto
 
     local iter,err = config.lines(file)
     if not iter then return nil,err end
diff --git a/lua/pl/data.lua b/lua/pl/data.lua
index 84f26bd..a565ebc 100644
--- a/lua/pl/data.lua
+++ b/lua/pl/data.lua
@@ -189,10 +189,6 @@ local function open_file (f,mode)
     return f,nil,opened
 end
 
-local function all_n ()
-
-end
-
 --- read a delimited file in a Lua table.
 -- By default, attempts to treat first line as separated list of fieldnames.
 -- @param file a filename or a file-like object
@@ -210,7 +206,7 @@ end
 -- @return error message. May be a file error, 'not a file-like object'
 -- or a conversion error
 function data.read(file,cnfg)
-    local err,opened,count,line
+    local count,line
     local D = {}
     if not cnfg then cnfg = {} end
     local f,err,opened = open_file(file,'r')
@@ -473,7 +469,6 @@ end
 
 local function process_select (data,parms)
     --- preparing fields ----
-    local res,ret
     field_error = nil
     local fields = parms.fields
     local numfields = fields:find '%$'  or #data.fieldnames == 0
@@ -495,7 +490,7 @@ local function process_select (data,parms)
         fields = rstrip(fields):gsub('[^,%w]','_')
     end
     local massage_fields = utils.bind1(massage_fields,data)
-    ret = gsub(fields,idpat,massage_fields)
+    local ret = gsub(fields,idpat,massage_fields)
     if field_error then return nil,field_error end
     parms.fields = fields
     parms.proc_fields = ret
@@ -555,7 +550,7 @@ function data.query(data,condn,context,return_row)
     else
         return nil, "condition must be a string or a table"
     end
-    local query, k
+    local query
     if condn.sort_by then -- use sorted_query
         query = sorted_query
     else
@@ -565,7 +560,7 @@ function data.query(data,condn,context,return_row)
     if return_row then
         fields = '{'..fields..'}'
     end
-    query,k = query:gsub('FIELDLIST',fields)
+    query = query:gsub('FIELDLIST',fields)
     if is_string(condn.where) then
         query = query:gsub('CONDITION',condn.where)
         condn.where = nil
@@ -636,7 +631,6 @@ end
 -- @param outfile filename or file-like object
 -- @bool dont_fail true if you want to return an error, not just fail
 function data.filter (Q,infile,outfile,dont_fail)
-    local err
     local d = data.read(infile or 'stdin')
     local out = open_file(outfile or 'stdout')
     local iter,err = d:select(Q)
diff --git a/lua/pl/dir.lua b/lua/pl/dir.lua
index 01b3be8..df37e84 100644
--- a/lua/pl/dir.lua
+++ b/lua/pl/dir.lua
@@ -198,7 +198,6 @@ local function file_op (is_copy,src,dest,flag)
         if not CopyFile then
             src = path.normcase(src)
             dest = path.normcase(dest)
-            local cmd = is_copy and 'copy' or 'rename'
             local res, err = execute_command('copy',two_arguments(src,dest))
             if not res then return false,err end
             if not is_copy then
@@ -379,7 +378,7 @@ function dir.clonetree (path1,path2,file_fun,verbose)
     if verbose then verbose('normalized:',path1,path2) end
     -- particularly NB that the new path isn't fully contained in the old path
     if path1 == path2 then return raise "paths are the same" end
-    local i1,i2 = path2:find(path1,1,true)
+    local _,i2 = path2:find(path1,1,true)
     if i2 == #path1 and path2:sub(i2+1,i2+1) == path.sep then
         return raise 'destination is a subdirectory of the source'
     end
diff --git a/lua/pl/func.lua b/lua/pl/func.lua
index 28c01d8..e2a0787 100644
--- a/lua/pl/func.lua
+++ b/lua/pl/func.lua
@@ -26,6 +26,7 @@ local tablex = require 'pl.tablex'
 local map = tablex.map
 local _DEBUG = rawget(_G,'_DEBUG')
 local assert_arg = utils.assert_arg
+local pack = table.pack or function(...) return { n = select("#", ...), ... } end
 
 local func = {}
 
@@ -165,9 +166,9 @@ local operators = {
     ['and'] = 1,
     ['=='] = 2, ['~='] = 2, ['<'] = 2, ['>'] = 2,  ['<='] = 2,   ['>='] = 2,
     ['..'] = 3,
-    ['+'] = 4, ['-'] = 4,
+    ['+'] = 4, ['-'] = 4,               -- luacheck: ignore
     ['*'] = 5, ['/'] = 5, ['%'] = 5,
-    ['not'] = 6, ['#'] = 6, ['-'] = 6,
+    ['not'] = 6, ['#'] = 6, ['-'] = 6,  -- TODO: fix the LuaCheck ignore above!
     ['^'] = 7
 }
 
@@ -335,7 +336,7 @@ end
 -- @usage (bind(f,_1,a))(b) == f(a,b)
 -- @usage (bind(f,_2,_1))(a,b) == f(b,a)
 function func.bind(fn,...)
-    local args = table.pack(...)
+    local args = pack(...)
     local holders,parms,bvalues,values = {},{},{'fn'},{}
     local nv,maxplace,varargs = 1,0,false
     for i = 1,args.n do
@@ -365,7 +366,7 @@ return function (%s)
 end
 ]]):format(bvalues,parms,holders)
     if _DEBUG then print(fstr) end
-    local res,err = utils.load(fstr)
+    local res = utils.load(fstr)
     res = res()
     return res(fn,unpack(values))
 end
diff --git a/lua/pl/lapp.lua b/lua/pl/lapp.lua
index 5ef42e9..56d1d9d 100644
--- a/lua/pl/lapp.lua
+++ b/lua/pl/lapp.lua
@@ -33,11 +33,10 @@ local function lines(s) return s:gmatch('([^\n]*)\n') end
 local function lstrip(str)  return str:gsub('^%s+','')  end
 local function strip(str)  return lstrip(str):gsub('%s+$','') end
 local function at(s,k)  return s:sub(k,k) end
-local function isdigit(s) return s:find('^%d+$') == 1 end
 
 local lapp = {}
 
-local open_files,parms,aliases,parmlist,usage,windows,script
+local open_files,parms,aliases,parmlist,usage,script
 
 lapp.callback = false -- keep Strict happy
 
@@ -182,7 +181,6 @@ end
 -- @return a table with parameter-value pairs
 function lapp.process_options_string(str,args)
     local results = {}
-    local opts = {at_start=true}
     local varargs
     local arg = args or _G.arg
     open_files = {}
@@ -219,7 +217,7 @@ function lapp.process_options_string(str,args)
 
     for line in lines(str) do
         local res = {}
-        local optspec,optparm,i1,i2,defval,vtype,constraint,rest
+        local optparm,defval,vtype,constraint,rest
         line = lstrip(line)
         local function check(str)
             return match(str,line,res)
@@ -314,7 +312,7 @@ function lapp.process_options_string(str,args)
                 end
                 ps.constraint = types[vtype].constraint
             elseif not builtin_types[vtype] and vtype then
-                lapp.error(vtype.." is unknown type")          
+                lapp.error(vtype.." is unknown type")
             end
             parms[optparm] = ps
         end
diff --git a/lua/pl/lexer.lua b/lua/pl/lexer.lua
index 071a62b..68a0874 100644
--- a/lua/pl/lexer.lua
+++ b/lua/pl/lexer.lua
@@ -267,7 +267,7 @@ end
 -- @param tok a token stream
 -- @return a string
 function lexer.getline (tok)
-    local t,v = tok('.-\n')
+    local _,v = tok('.-\n')
     return v
 end
 
@@ -284,7 +284,7 @@ end
 -- @param tok a token stream
 -- @return a string
 function lexer.getrest (tok)
-    local t,v = tok('.+')
+    local _,v = tok('.+')
     return v
 end
 
diff --git a/lua/pl/luabalanced.lua b/lua/pl/luabalanced.lua
index a75f6fd..a1f7dc6 100644
--- a/lua/pl/luabalanced.lua
+++ b/lua/pl/luabalanced.lua
@@ -130,6 +130,7 @@ local wordop = {['and']=true, ['or']=true, ['not']=true}
 local is_compare = {['>']=true, ['<']=true, ['~']=true}
 local function match_expression(s, pos)
   pos = pos or 1
+  local _
   local posa = pos
   local lastident
   local poscs, posce
@@ -149,7 +150,7 @@ local function match_expression(s, pos)
         posce = pos
       end
     elseif c == '(' or c == '{' or c == '[' then
-      local part; part, pos = match_bracketed(s, pos)
+      _, pos = match_bracketed(s, pos)
     elseif c == '=' and s:sub(pos+1,pos+1) == '=' then
       pos = pos + 2  -- skip over two-char op containing '='
     elseif c == '=' and is_compare[s:sub(pos-1,pos-1)] then
diff --git a/lua/pl/path.lua b/lua/pl/path.lua
index f8f3d78..5979e8e 100644
--- a/lua/pl/path.lua
+++ b/lua/pl/path.lua
@@ -128,7 +128,7 @@ else
     path.sep = '/'
     path.dirsep = ':'
 end
-local sep,dirsep = path.sep,path.dirsep
+local sep = path.sep
 
 --- are we running Windows?
 -- @class field
@@ -205,7 +205,7 @@ end
 -- @string P A file path
 function path.dirname(P)
     assert_string(1,P)
-    local p1,p2 = path.splitpath(P)
+    local p1 = path.splitpath(P)
     return p1
 end
 
@@ -213,7 +213,7 @@ end
 -- @string P A file path
 function path.basename(P)
     assert_string(1,P)
-    local p1,p2 = path.splitpath(P)
+    local _,p2 = path.splitpath(P)
     return p2
 end
 
@@ -221,7 +221,7 @@ end
 -- @string P A file path
 function path.extension(P)
     assert_string(1,P)
-    local p1,p2 = path.splitext(P)
+    local _,p2 = path.splitext(P)
     return p2
 end
 
@@ -326,13 +326,6 @@ function path.normpath(P)
     return P
 end
 
-local function ATS (P)
-    if at(P,#P) ~= path.sep then
-        P = P..path.sep
-    end
-    return path.normcase(P)
-end
-
 --- relative path from current directory or optional start point
 -- @string P a path
 -- @string[opt] start optional start point (default current directory)
diff --git a/lua/pl/permute.lua b/lua/pl/permute.lua
index 56d1a8d..732500b 100644
--- a/lua/pl/permute.lua
+++ b/lua/pl/permute.lua
@@ -43,7 +43,7 @@ function permute.iter (a)
     local n = #a
     local co = coroutine.create(function () permgen(a, n, coroutine.yield) end)
     return function ()   -- iterator
-        local code, res = resume(co)
+        local _, res = resume(co)
         return res
     end
 end
diff --git a/lua/pl/pretty.lua b/lua/pl/pretty.lua
index 7365ad3..a9abe0e 100644
--- a/lua/pl/pretty.lua
+++ b/lua/pl/pretty.lua
@@ -7,7 +7,8 @@
 
 local append = table.insert
 local concat = table.concat
-local mfloor, mhuge, mtype = math.floor, math.huge, math.type
+local mfloor, mhuge = math.floor, math.huge
+local mtype = math.type
 local utils = require 'pl.utils'
 local lexer = require 'pl.lexer'
 local debug = require 'debug'
@@ -46,12 +47,12 @@ local pretty = {}
 local function save_global_env()
     local env = {}
     env.hook, env.mask, env.count = debug.gethook()
-    
+
     -- env.hook is "external hook" if is a C hook function
     if env.hook~="external hook" then
         debug.sethook()
     end
-    
+
     env.string_mt = getmetatable("")
     debug.setmetatable("", nil)
     return env
@@ -210,7 +211,7 @@ function pretty.write (tbl,space,not_clever)
     end
 
     local function eat_last_comma ()
-        local n,lastch = #lines
+        local n = #lines
         local lastch = lines[n]:sub(-1,-1)
         if lastch == ',' then
             lines[n] = lines[n]:sub(1,-2)
diff --git a/lua/pl/seq.lua b/lua/pl/seq.lua
index c867add..1c08d20 100644
--- a/lua/pl/seq.lua
+++ b/lua/pl/seq.lua
@@ -79,9 +79,9 @@ end
 -- @return iterator over keys
 function seq.keys(t)
   assert_arg(1,t,'table')
-  local key,value
+  local key
   return function()
-    key,value = next(t,key)
+    key = next(t,key)
     return key
   end
 end
@@ -511,7 +511,6 @@ setmetatable(seq,{
 -- @param ... for Lua 5.2 only, optional format specifiers, as in `io.read`.
 -- @return a sequence wrapper
 function seq.lines (f,...)
-    local n = select('#',...)
     local iter,obj
     if f == 'STDIN' then
         f = io.stdin
diff --git a/lua/pl/strict.lua b/lua/pl/strict.lua
index d4e0fc7..ab7875f 100644
--- a/lua/pl/strict.lua
+++ b/lua/pl/strict.lua
@@ -28,10 +28,9 @@ end
 -- @tab[opt] predeclared - table of variables that are to be considered predeclared.
 -- @return the given table, or a new table
 function strict.module (name,mod,predeclared)
-    local mt, old_newindex, old_index, old_index_type, global, closed
+    local mt, old_newindex, old_index, old_index_type, global
     if predeclared then
         global = predeclared.__global
-        closed = predeclared.__closed
     end
     if type(mod) == 'table' then
         mt = getmetatable(mod)
@@ -71,13 +70,13 @@ function strict.module (name,mod,predeclared)
                     local fallback = old_index[n]
                     if fallback ~= nil then
                         return fallback
-                    end 
+                    end
                 else
                     local res = old_index(t, n)
                     if res ~= nil then
                         return res
                     end
-                end 
+                end
             end
             local msg = "variable '"..n.."' is not declared"
             if name then
diff --git a/lua/pl/stringio.lua b/lua/pl/stringio.lua
index 10fd102..666f415 100644
--- a/lua/pl/stringio.lua
+++ b/lua/pl/stringio.lua
@@ -72,7 +72,7 @@ function SR:_read(fmt)
         res = str:sub(i)
         self.i = sz
     elseif fmt == '*n' then
-        local _,i2,i2,idx
+        local _,i2,idx
         _,idx = str:find ('%s*%d+',i)
         _,i2 = str:find ('^%.%d+',idx+1)
         if i2 then idx = i2 end
diff --git a/lua/pl/stringx.lua b/lua/pl/stringx.lua
index adf1070..8bcc6a2 100644
--- a/lua/pl/stringx.lua
+++ b/lua/pl/stringx.lua
@@ -274,7 +274,7 @@ end
 -- @string sub substring
 function stringx.count(s,sub)
     assert_string(1,s)
-    local i,k = _find_all(s,sub,1)
+    local _,k = _find_all(s,sub,1)
     return k
 end
 
@@ -499,17 +499,16 @@ end
 -- @return 'nil' if not found. If found, the maximum number of equal signs found within all matches.
 local function has_lquote(s)
     local lstring_pat = '([%[%]])(=*)%1'
-    local equals
-    local start, finish, bracket, new_equals = nil, 1, nil, nil
-
+    local equals, new_equals, _
+    local finish = 1
     repeat
-        start, finish, bracket, new_equals = s:find(lstring_pat, finish)
+        _, finish, _, new_equals = s:find(lstring_pat, finish)
         if new_equals then
             equals = max(equals or 0, #new_equals)
         end
     until not new_equals
 
-    return equals 
+    return equals
 end
 
 --- Quote the given string and preserve any control or escape characters, such that reloading the string in Lua returns the same result.
@@ -530,8 +529,8 @@ function stringx.quote_string(s)
         equal_signs = ("="):rep((equal_signs or -1) + 1)
         -- Long strings strip out leading newline. We want to retain that, when quoting.
         if s:find("^\n") then s = "\n" .. s end
-        local lbracket, rbracket =  
-            "[" .. equal_signs .. "[",  
+        local lbracket, rbracket =
+            "[" .. equal_signs .. "[",
             "]" .. equal_signs .. "]"
         s = lbracket .. s .. rbracket
     else
diff --git a/lua/pl/template.lua b/lua/pl/template.lua
index 2f97e8f..9961a1b 100644
--- a/lua/pl/template.lua
+++ b/lua/pl/template.lua
@@ -60,8 +60,9 @@ local function parseHashLines(chunk,inline_escape,brackets,esc,newline)
     local esc_pat1, esc_pat2 = "^"..esc_pat, "\n"..esc_pat
     local  pieces, s = {"return function()\nlocal __R_size, __R_table, __tostring = 0, {}, __tostring", n = 1}, 1
     while true do
-        local ss, e, lua = strfind(chunk,esc_pat1, s)
+        local _, e, lua = strfind(chunk,esc_pat1, s)
         if not e then
+            local ss
             ss, e, lua = strfind(chunk,esc_pat2, s)
             parseDollarParen(pieces, strsub(chunk,s, ss), exec_pat, newline)
             if not e then break end
diff --git a/lua/pl/test.lua b/lua/pl/test.lua
index 87f88f0..ddf8345 100644
--- a/lua/pl/test.lua
+++ b/lua/pl/test.lua
@@ -16,6 +16,7 @@ local type,unpack = type,utils.unpack
 local clock = os.clock
 local debug = require 'debug'
 local io = io
+local pack = table.pack or function(...) return { select("#", ...), ...} end
 
 local function dump(x)
     if type(x) == 'table' and not (getmetatable(x) and getmetatable(x).__tostring) then
@@ -85,11 +86,11 @@ end
 -- @param e a string to match the error against
 -- @param where extra level offset
 function test.assertraise(fn,e,where)
-    local ok, err
+    local _, err
     if type(fn) == 'table' then
-        ok, err = pcall(unpack(fn))
+        _, err = pcall(unpack(fn))
     else
-        ok, err = pcall(fn)
+        _, err = pcall(fn)
     end
     if not err or err:match(e)==nil then
         complain (err,e,"these errors did not match",where)
@@ -112,7 +113,7 @@ end
 -- tuple type --
 
 local tuple_mt = {
-    unpack = table.unpack
+    unpack = unpack
 }
 tuple_mt.__index = tuple_mt
 
@@ -146,7 +147,7 @@ end
 -- and there is an `unpack` method.
 -- @usage asserteq(tuple( ('ab'):find 'a'), tuple(1,1))
 function test.tuple(...)
-    return setmetatable(table.pack(...), tuple_mt)
+    return setmetatable(pack(...), tuple_mt)
 end
 
 --- Time a function. Call the function a given number of times, and report the number of seconds taken,
diff --git a/lua/pl/text.lua b/lua/pl/text.lua
index d18fcc0..341e2bf 100644
--- a/lua/pl/text.lua
+++ b/lua/pl/text.lua
@@ -68,7 +68,7 @@ end
 function text.dedent (s)
     assert_arg(1,s,'string')
     local sl = split(s,'\n')
-    local i1,i2 = (#sl>0 and sl[1] or ''):find('^%s*')
+    local _,i2 = (#sl>0 and sl[1] or ''):find('^%s*')
     sl = imap(string.sub,sl,i2+1)
     return concat(sl,'\n')..'\n'
 end
diff --git a/lua/pl/utils.lua b/lua/pl/utils.lua
index da3e327..bcd0e01 100644
--- a/lua/pl/utils.lua
+++ b/lua/pl/utils.lua
@@ -268,7 +268,6 @@ end
 -- @return stdout output (string)
 -- @return errout output (string)
 function utils.executeex(cmd, bin)
-    local mode
     local outfile = os.tmpname()
     local errfile = os.tmpname()
 
diff --git a/lua/pl/xml.lua b/lua/pl/xml.lua
index ae26f5e..4650a32 100644
--- a/lua/pl/xml.lua
+++ b/lua/pl/xml.lua
@@ -186,7 +186,6 @@ end
 --  doc = parent {child 'one', child 'two'}
 function _M.tags(list)
     local ctors = {}
-    local elem = _M.elem
     if is_text(list) then list = split(list,'%s*,%s*') end
     for _,tag in ipairs(list) do
         local ctor = function(items) return _M.elem(tag,items) end
@@ -572,9 +571,10 @@ function _M.basic_parse(s,all_text,html)
 
     t_insert(stack, top)
     local ni,c,label,xarg, empty, _, istart
-    local i, j = 1, 1
+    local i = 1
+    local j
     -- we're not interested in <?xml version="1.0"?>
-    _,istart = s_find(s,'^%s*<%?[^%?]+%?>%s*')    
+    _,istart = s_find(s,'^%s*<%?[^%?]+%?>%s*')
     if not istart then -- or <!DOCTYPE ...>
         _,istart = s_find(s,'^%s*<!DOCTYPE.->%s*')
     end
@@ -596,8 +596,6 @@ function _M.basic_parse(s,all_text,html)
             if html then
                 label = label:lower()
                 if html_empty_elements[label] then empty = "/" end
-                if label == 'script' then
-                end
             end
             if all_text or not s_find(text, "^%s*$") then
                 t_insert(top, unescape(text))
@@ -619,7 +617,7 @@ function _M.basic_parse(s,all_text,html)
                 t_insert(top, toclose)
             end
         end
-    i = j+1
+        i = j+1
     end
     local text = s_sub(s, i)
     if all_text or  not s_find(text, "^%s*$") then