Re: LPEG bug?

[Hisham <h@...>]

On 17 May 2015 at 15:41, Dirk Laurie <dirk.laurie@gmail.com> wrote:
> 2015-05-17 12:36 GMT+02:00 Daurnimator <quae@daurnimator.com>:
>> Today I was working on an lpeg pattern, and ran into this oddity,
>> which I believe to be a bug.
>> I've condensed it down as far as I could, if I remove any more the bug
>> seems to disappear.
>>
>> The following script throws in the assert.
>> If you uncomment either of the alternate `path_abempty` definitions, it works.
>>
>>
>>
>> local lpeg = require "lpeg"
>> local P = lpeg.P
>> local HEXDIG = lpeg.R("09","af", "AF")
>> local pct_encoded = P"%" * lpeg.C ( HEXDIG * HEXDIG ) / function (hex_num)
>> return string.char(tonumber(hex_num, 16))
>> end
>> local pchar         = lpeg.R("az","AZ") + pct_encoded
>> local path_abempty  = ( P"/" * pchar^0 )^0
>> -- local path_abempty  = ( P"/" * pchar^0 )^0 * ( P"/" * pchar^0 )^0
>> -- local path_abempty  = ( P"/" * pchar^0 )^0 * function() return true end
>> local path_rootless = pchar^1 * path_abempty
>> local path_absolute = P"/" * path_rootless^-1
>>
>> assert(lpeg.Cs ( path_absolute ):match "/var/log/messages" ==
>> "/var/log/messages")
>>
>
> I don't even get this far. A freshly built LPEG does not load.
> This is 64-bit Ubuntu 14.04 with Lua 5.3 installed under the
> default directory /usr/local.
>
> $ sudo luarocks install lpeg
> [sudo] password for dirk:
> Installing https://rocks.moonscript.org/lpeg-0.12.2-1.src.rock...
> Using https://rocks.moonscript.org/lpeg-0.12.2-1.src.rock... switching
> to 'build' mode
> gcc -O2 -fPIC -I/home/dirk/include -c lpcap.c -o lpcap.o
> gcc -O2 -fPIC -I/home/dirk/include -c lpcode.c -o lpcode.o
> gcc -O2 -fPIC -I/home/dirk/include -c lpprint.c -o lpprint.o
> gcc -O2 -fPIC -I/home/dirk/include -c lptree.c -o lptree.o
> gcc -O2 -fPIC -I/home/dirk/include -c lpvm.c -o lpvm.o
> gcc -shared -o lpeg.so -L/home/dirk/lib lpcap.o lpcode.o lpprint.o
> lptree.o lpvm.o
> Updating manifest for /usr/local/lib/luarocks/rocks
> lpeg 0.12.2-1 is now built and installed in /usr/local (license: MIT/X11)
>
> $ luarocks show lpeg
>
> LPeg 0.12.2-1 - Parsing Expression Grammars For Lua
>
> LPeg is a new pattern-matching library for Lua, based on Parsing Expression
> Grammars (PEGs). The nice thing about PEGs is that it has a formal basis
> (instead of being an ad-hoc set of features), allows an efficient and simple
> implementation, and does most things we expect from a pattern-matching library
> (and more, as we can define entire grammars).
>
> License:     MIT/X11
> Homepage:     http://www.inf.puc-rio.br/~roberto/lpeg.html
> Installed in:     /usr/local
>
> Modules:
>     lpeg (/usr/local/lib/lua/5.3/lpeg.so)
>     re (/usr/local/share/lua/5.3/re.lua)
>
> $ lua -v -l lpeg
> Lua 5.3.0  Copyright (C) 1994-2015 Lua.org, PUC-Rio
> lua: error loading module 'lpeg' from file '/usr/local/lib/lua/5.3/lpeg.so':
>     /usr/local/lib/lua/5.3/lpeg.so: undefined symbol: lua_replace
> stack traceback:
>     [C]: in ?
>     [C]: in function 'require'
>     [C]: in ?

Looks like your Lua install doesn't match your lua.h headers. Note
that at build time it's picking stuff from /home/dirk/include and
/home/dirk/lib. Do you have another Lua version in there?

-- Hisham