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Hi list!

I'm currently using Lua to store small amounts of record-like data in Lua files, using a syntax similar to the following:

-- file table1.lua
Record('field1', 'field2', 1231)
Record('field1', 'field2', 1231)

or this one:

-- file table2.lua

Record{ id = 3232, name = 'foo', date = '2010-12-25' }
Record{ id = 1232, name = 'bar', date = '2010-12-31' }

Then, after suitably defining the function 'Record', I load those files using 'dofile' and process the data in different ways.

Currently I use ad-hoc functions to perform validation on the data, but this is becoming unwieldy, since I find this kind of storage very useful and flexible and I keep creating these small files (say max 1000 records with max 10-20 fields each) for various purposes, and the ad-hoc validation functions are becoming the main maintenance hassle. Sometimes the task gets even more complicated when a field is actually a Lua table itself, so the validation routine must recurse into it.

Is there any _very lightweight_ Lua library (pure Lua possibly) which could help me in this respect, ie. defining a sort of a pseudo-DB schema in a clean way and then use it to validate tables?

I'd like to write something declarative like:

local scheme = NewScheme {
  -- fields description
  id = {
    type = 'number',
    validator = function(field) ... end -- returns true when 'id' is ok
 name = {
    type = 'string',
    validator = function(field) ... end
-- etc.

and then in the 'Record' function:

if not scheme:validate(record)	
  then error(...) end

I'd really like to avoid using a true RDBMS, even simple as sqlite, since I love the format of the Lua 'data files' (and the advantages they provide) and most of the time I don't need to update the data in the tables: I only add records at the end manually or with simple append procedures from other scripts (even non-Lua).

Any pointer or suggestion are welcome as long as it allows me to retain the data files format and it is lightweight (not necessarily a library, even a different approach at table data validation, if there is some neat Lua trick that can improve readability and maintenance!).

Thanks in advance!