Re: On the subject of Lua's grammar... --[[ ]]

["Leandro Candido" <enclle@...>]

Hello all,

    Thank you Philipp for the code, you only forgot the userdata type
 metamethods, etc.. ). In my opinion, it's best to have in the language
itself, as this speed up the code and can use the parser to check types,
etc...

                                                                    The
God's Peace,


Leandro.

----- Original Message -----
From: "Philipp Janda" <siffiejoe@gmx.net>
To: <lua@bazar2.conectiva.com.br>
Sent: Friday, November 28, 2003 6:50 AM
Subject: Re: On the subject of Lua's grammar... --[[ ]]


> Leandro Candido schrieb:
> > Hello all,
> >
> >
> >     As we are in suggestion time, i will make my one. Can you guys add
range
> > operator? To use like:
> >
> >     for x in 0..10 do print(x) end or
> >     for x in 'A'..'Z' do print(x) end
> >
> >     Of course the .. need be other letters/signs or we need to change
the
> > concat operator, because it is "..".
> >     Perhaps the best is the word "to":
> >
> >     for x in 0 to 10 do print(x) end, y = 0 to 10 or y = { 0 to 10 } --
> > equal y = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }
>
> What about this:
>
> local function num_range_iterator( state, var1 )
>    -- state is the end of the iteration
>    var1 = var1 + 1
>    if var1 > state then
>      return nil
>    end
>    return var1
> end
>
> local function char_range_iterator( state, var1 )
>    -- state is the end of the iteration
>    local ret = num_range_iterator( state, string.byte( var1 ) )
>    return ret and string.char( ret )
> end
>
>
> function range( start, ending )
>    local stype, etype = type( start ), type( ending )
>    if stype == "string" and etype == "string" then
>      return char_range_iterator, string.byte( ending ),
>             string.char( string.byte( start )-1 )
>    elseif stype == "number" and etype == "number" then
>      return num_range_iterator, ending, start-1
>    else
>      error( "type error in function `range' (strings or numbers
expected)" )
>    end
> end
>
>
> function from_to( start, ending )
>    local tab = {}
>    for x in range( start, ending ) do
>      table.insert( tab, x )
>    end
>    return unpack( tab )
> end
>
> --------- test -------------------------------------------------------
>
>
> for x in range( 1, 10 ) do
>    print( x )
> end
>
> for x in range( 'A', 'Z' ) do
>    print( x )
> end
>
> local y = { from_to( 1, 10 ) }
> for i,j in ipairs( y ) do
>    print( i, j )
> end
>
>
>
>
> Philipp
>
>
>