It seems that documents in `http://metalua.luaforge.net/` are out of date

[tan-wei]

For example, I can't run with the example in quick tour:

---------------------------------------------------------
-- the "-{...}" means that we're going to do compile-time
-- stuff (here, syntax extension) 
---------------------------------------------------------
-{ block:
   ------------------------------------------------------
   -- Register the additional keywords in mlp.lexer
   ------------------------------------------------------
   mlp.lexer:add{ "let", "in" }

   ------------------------------------------------------
   -- Extend the expression parser; code generation is
   -- delegated to the function let_in_builder() below.
   ------------------------------------------------------
   mlp.expr:add{ 
     "let", mlp.id, "=", mlp.expr, "in", mlp.expr, 
     builder = let_in_builder }

   ------------------------------------------------------
   -- This creates the code returned by the macro.
   -- Notice the holes-in-quote-in-splice.
   ------------------------------------------------------
   local function let_in_builder (x)
     local variable, value, expr = unpack (x)
     return +{
       function (-{variable}) 
         return -{expr} 
       end (-{value}) }
   end
} -- back to "normal" code
 
a, b, c = 1, 1, -2 
roots = let sqrt_delta = (b^2-4*a*c)^0.5 in 
        { (sqrt_delta-b)/(2*a), (-sqrt_delta-b)/(2*a) } 

It fails with these error messages:

C:\Program Files (x86)\LuaRocks\lua5.1: splice:9: attempt to index global 'mlp' (a nil value)
stack traceback:
        splice:9: in function 'f'
        ...stree/share/lua/5.1/metalua\compiler\parser\meta.lua:41: in function <...stree/share/lua/5.1/metalua\compiler\parser\meta.lua:37>
        (tail call): ?
        (tail call): ?
        ...\systree/share/lua/5.1/metalua\grammar\generator.lua:113: in function 'raw_parse_sequence'
        ...\systree/share/lua/5.1/metalua\grammar\generator.lua:216: in function <...\systree/share/lua/5.1/metalua\grammar\generator.lua:212>
        (tail call): ?
        (tail call): ?
        ...\systree/share/lua/5.1/metalua\grammar\generator.lua:332: in function <...\systree/share/lua/5.1/metalua\grammar\generator.lua:330>
        (tail call): ?
        ...
        (tail call): ?
        ...stree/share/lua/5.1/metalua\compiler\parser\misc.lua:164: in function 'e'
        ...\systree/share/lua/5.1/metalua\grammar\generator.lua:113: in function 'raw_parse_sequence'
        ...\systree/share/lua/5.1/metalua\grammar\generator.lua:216: in function <...\systree/share/lua/5.1/metalua\grammar\generator.lua:212>
        (tail call): ?
        ...\LuaRocks\systree/share/lua/5.1/metalua\compiler.lua:104: in function 'f'
        ...\LuaRocks\systree/share/lua/5.1/metalua\compiler.lua:153: in function 'srcfile_to_ast'
        ...e\lib\luarocks\rocks-5.1\metalua\0.7.3-1\bin\metalua:162: in function <...e\lib\luarocks\rocks-5.1\metalua\0.7.3-1\bin\metalua:105>
        (tail call): ?
        [C]: ?

Lots of examples shown in the website fail, I think it's because of the older documents. mlp, clist do not exist for now.