Migrating To Five One

wiki

Living without table.setn() and table.getn()

• TODO - No more 'lying' about size...unless you roll your own
• TODO - The length operator
• TODO - table.maxn()

Using vararg expressions rather than 'arg'

• 5.0

function catchall( ... )
   for i=1,arg.n do
      print( "Argument #", i, "is", arg[ i ] )
   end

   -- Pass all arguments to another function
   show3( unpack( arg ) )
end

function show3( a, b, c )
   print( a, b, c )
end

catchall( nil, 'two', nil )
--> Argument #    1     is     nil
--> Argument #    2     is     two
--> Argument #    3     is     nil
--> nil     two     nil

• 5.1

function catchall( ... )
   -- Make a new table of values
   local theArguments = { ... }

   for i=1,select( '#', ... ) do
      print( "Argument #", i, "is", theArguments[ i ] )
   end

   -- Pass all arguments to another function
   show3( ... )
end

function show3( a, b, c )
   print( a, b, c )
end

catchall( nil, 'two', nil )
--> Argument #    1     is     nil
--> Argument #    2     is     two
--> Argument #    3     is     nil
--> nil     two     nil

• ipairs() will stop at the first embedded nil value;
• # (the length operator) [may] stop at the first embedded nil value;
• table.maxn() will skip embedded nil values; but
• Only select( '#', ... ) will allow you to see that the user passed in trailing nil values.

Nesting long strings or block comments

• TODO - Must differentiate levels. Allows for XML CDATA, e.g.

Working with Garbage Collection

• TODO - new arguments to collectgarbage()

Simple Find/Replace Changes

• TODO - gfind to gmatch
• TODO - loadlib to package.loadlib
• TODO - math.mod to math.fmod or %

Strings as 'objects'

• TODO - string.rep( 'x', 10 ) versus ('x'):rep( 10 )

C API Changes

• ???
• Roberto sez: All luaL_check* functions should be called only with positive indices (more specifically, with indices to parameters). Workaround:

if (index < 0 && -index <= top)
    index = top+index+1;
my* = luaL_check*(L, index, ...);

Migrating with Specific Addons or Libraries

• Copy the definitions of lua_boxpointer and lua_unboxpointer from the 5.0 lua.h
• Replace the uses of luaL_findstring with luaL_checkoption. If necessary, copy the code of luaL_findstring from 5.0.

New Module System

• module("modulename", package.seeall) - Unexpected results from just module("modulename")
• Use 5.1 package.loadlib for 5.0 uses of loadlib