Re: module 'pylist' not found

[Gabriel Duarte <confusosk8@...>]

Did you read the whole page?

The code of pylist module is there, you just had to copy it, put into a file and name it as pylist.lua.

After that, just "require" it inside Lua. To make your life easier, I did it for you :)

The module is attached to this email. Have fun!

On Sat, Jul 23, 2011 at 9:15 PM, Igor G. <eazyigz@gmail.com> wrote:

Hello,

I am following the tutorial on http://lua-users.org/wiki/PythonLists.  When I do require 'pylist', I get an error: 

module 'pylist' not found

What gives??  I am totally new to Lua...

Thank you,
Igor Ganapolsky

--
Gabriel Duarte
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Rio de Janeiro - RJ
http://genericdev.wordpress.com/

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-- Emulation of Python lists
-- Nick Trout
-- See http://www.python.org/doc/current/tut/tut.html, section 5.1
-- Note:The comments before some of the functions are from the Python docs
-- and contain Python code.
-- Written for Lua version 4.0
-- Redone for Lua 5.1, Steve Donovan.

local tinsert = table.insert
local tremove = table.remove
local tsort = table.sort
local write = io.write

-- metatable for our list objects
List = {}
List.__index = List
-- we give the metatable its own metatable so that we can call it like a function!
_ListMT = {}
setmetatable(List,_ListMT)
function _ListMT.__call(tbl,arg)
  return List:new(arg)
end

-- Handle the index event
-- note: this is called if something is _not_ present in the table. These are either 
-- negative indices, method names, or bad indices.
function List:__index(i)
  local typ = type(i)
  if typ=="string" then
    local fn = List[i]
    if not fn then error("Bad List function: "..i) end
    return fn
  elseif typ=="number" then
    if i<0 then
      local sz = #self
      if i<-sz then error("List index out of range: "..i) end
      return self[sz+i+1]
    else
      error("Bad list index: "..i)
    end
  end
end

-- The newindex event handles list[i] = val, if i is not present in 
-- the list - used for negative indices!
function List:__newindex(i,val)
  if type(i)=="number" then
    if i<0 then
      local sz = #self
      if i<-sz then error("List index out of range: "..i) end
      self[sz+i+1] = val
    else
      error("Bad list index: "..i)
    end
  end
end

local function simple_table(t)
  return type(t) == 'table' and getmetatable(t) ~= List
end

-- Create a new list. Can optionally pass a list eg. x=List:new{1,2,3}
-- passing another instance of List will cause a _copy_ to be created
-- we pass anything which isn't a simple table to iter() to work out
-- an appropriate iterator
function List:new(t)
  if not t then t={} 
  elseif  not simple_table(t) then
    local tbl = t
    t = {}
    for i,v in iter(tbl) do
      tinsert(t,v)
    end
  end
  setmetatable(t,List)
  return t
end

--Add an item to the end of the list; equivalent to a[len(a):] = [x].
function List:append(i)
  tinsert(self,i)
end

-- Extend the list by appending all the items in the given list;
-- equivalent to a[len(a):] = L.
function List:extend(L)
  assert(type(L)=="table","List:extend expecting a table")
  for i,v in ipairs(L) do tinsert(self,v) end
end

-- Insert an item at a given position. The first argument is the index of the
-- element before which to insert, so a.insert(0, x) inserts at the front of
-- the list, and a.insert(len(a), x) is equivalent to a.append(x).
function List:insert(i, x)
  tinsert(self,i,x)
end

-- equivalent of Python's del s[i]
List.delete = tremove

-- Remove the first item from the list whose value is x.
-- It is an error if there is no such item.
function List:remove(x)
  for i=1,#self do
    if self[i]==x then tremove(self,i) return end
  end
  error("List:remove failed, item not found")
end

-- Remove the item at the given position in the list, and return it.
-- If no index is specified, a.pop() returns the last item in the list.
-- The item is also removed from the list.
function List:pop(i)
  if not i then i = #self end
  return tremove(self,i)
end

-- Return the index in the list of the first item whose value is x.
-- It is an error if there is no such item.
function List:index(x)
  for i=1,#self do
    if self[i]==x then return i end
  end
  error("List:index failed, item not found")
end

-- Return the number of times x appears in the list.
function List:count(x)
  local cnt=0
  for i=1,#self do
    if self[i]==x then cnt=cnt+1 end
  end
  return cnt
end

-- Sort the items of the list, in place.
function List:sort()
  tsort(self)
end

-- Reverse the elements of the list, in place.
function List:reverse()
  local t,n={},#self
  for i=1,n do t[i]=self[n-i+1] end -- reverse
  for i=1,n do self[i]=t[i] end -- copy back
end

local function normalize_slice(self,first,last)
  local sz = #self
  if not first then first=1 end
  if first<0 then first=sz+first+1 end
  -- make the range _inclusive_!
  if not last then last=sz end 
  if last < 0 then last=sz+last end
  return first,last
end

-- Emulate the list slice eg. python_list[first:last]
-- If first or last are negative then they are relative to the end of the list
-- eg. slice(-2) gives last 2 entries in a list,
-- eg. slice(-4,-2) gives from -4th to -2nd
function List:slice(first,last)
  first,last = normalize_slice(self,first,last)
  local t=self:new()
  for i=first,last do tinsert(t,self[i]) end
  return t
end

-- empty the list
function List:clear()
  for i=1,#self do tremove(self,i) end
end

-- Emulate Python's range(x) function which gives you a sequence of 0..x-1
-- Include it in List table for tidyness
function List:range(x)
  local t=self
  if type(t) == 'number' then -- we did not get a self argument - it was a number!
    x = t
    t=List:new()    
  end
  for i=0,x-1 do tinsert(t,i) end
  return t
end

-- Python len(list) is the same as #list
function List:len()
  return #self
end

-- Extended operations --

-- equivalent to del s[i1:i2]
function List:chop(i1,i2)
    i1,i2 = normalize_slice(self,i1,i2)
    for i = i1,i2 do
        tremove(self,i1)
    end
end

-- equivalent to s[idx:idx] = seq
function List:splice(idx,seq)
    idx = idx - 1
    for i,v in ipairs(seq) do
        tinsert(self,i+idx,v)
    end
end

-- general slice assignment s[i1:i2] = seq
function List:slice_assign(i1,i2,seq)
    i1,i2 = normalize_slice(self,i1,i2)
    if i2 >= i1 then self:chop(i1,i2) end
    self:splice(i1,seq)
end

-- concatenation operator ..
function List:__concat(L)
  local ls = self:slice(1,-1)  -- making a copy!
  ls:extend(L)
  return ls
end

-- equality operator ==
function List:__eq(L)
--~   print(#self,#L)
  if #self ~= #L then return false end
  for i = 1,#self do
--~     print(self[i],L[i])
    if self[i] ~= L[i] then return false end
  end
  return true
end

-- how our list should be rendered as a string
-- note: really can't handle list items which are not strings or numbers
function List:__tostring()
  return '{'..table.concat(self,',')..'}'
end

-- can use the call notation to extract slices!
function List:__call(first,last)
  return self:slice(first,last)
end

function List:foreach(fun)
  for i,v in ipairs(self) do
    fun(v)
  end
end

-- capturing the Python concept of 'sequence'. 
-- In particular, this makes strings and file objects to be iterable sequences.
function iter(seq)
    if type(seq) == 'string' then
        local idx = 0
        local n = #seq
        local sub = string.sub
        return function ()
            idx = idx + 1
            if idx > n then return nil
            else
                return idx,sub(seq,idx,idx)
            end
        end
    elseif type(seq) == 'table' then
        return ipairs(seq)
    elseif type(seq) == 'function' then
        return seq()
    elseif type(seq) == 'userdata' and io.type(seq) == 'file' then
        local lines = seq:lines()
        local k = 0
        return function ()
            local line = lines()
            if not line then
              return nil 
            else
                k = k + 1
                return k,line
            end
        end			
    end
end