bug in Lpeg re.lua

["Fabio Mascarenhas" <mascarenhas@...>]

Hi,

There's a bug in re.lua that manifests when you use re grammars with a definitions table:

require"lpeg"
require"re"

local grammar = [[
   foo <- bar
   bar <- baz
]]

local defs = { baz = lpeg.P"baz" }

exp = re.compile(grammar, defs)
print(re:match"baz")

This code blows up with:

lua: ./re.lua:103: bad argument #1 to 'P' (pattern expected, got nil)
stack traceback:
        [C]: in function 'P'
        ./re.lua:103: in function <./re.lua:102>
        [C]: in function 'match'
        ./re.lua:133: in function 'compile'
        foo.lua:11: in main chunk
        [C]: ?

The attached patch fixes this.

--
Fabio Mascarenhas

--- re.lua	2007-10-10 15:56:59.000000000 -0300
+++ ../lpeg-0.7-patched/re.lua	2008-01-23 04:44:08.000000000 -0200
@@ -5,7 +5,7 @@
 local print, error = print, error
 local mt = getmetatable(m.P(0))
 
-module "re"
+module(...)
 
 local I = m.P(function (s,i) print(i, s:sub(1, i-1)); return i end)
 
@@ -100,7 +100,7 @@
             + Class
             + m.P"." * m.Cc(any)
             + Identifier * -(S * '<-') / function (n)
-                return Defs and m.P(Defs[n]) or m.V(n)
+                return (Defs and Defs[n] and m.P(Defs[n])) or m.V(n)
               end;
 }