[ANN] safer - Paranoid Lua programming

[Hisham <h@...>]

Hi,

Announcing yet another "strict-mode" style module: "safer".

* http://github.com/hishamhm/safer

Install with
   luarocks install safer

# Safer - Paranoid Lua programming

Taking defensive programming to the next level. Use this module
to avoid unexpected globals creeping up in your code, and stopping
sub-modules from fiddling with fields of tables as you pass them
around.

## API

#### `safer.globals([exception_globals], [exception_nils])`

No new globals after this point.

`exception_globals` is an optional set (keys are strings, values are
`true`) specifying names to be exceptionally accepted as new globals.
Use this in case you have to declare a legacy module that declares a
global, for example. A few legacy modules are already handled by
default.

`exception_nils` is an optional set (keys are strings, values are
`true`) specifying names
to be exceptionally accepted to be accessed as nonexisting globals.
Use this in case code does feature-testing based on checking the
presence of globals. A few common feature-test nils such as `jit` and
`unpack` are already handled by default.

#### `t = safer.table(t)`

Block creation of new fields in this table.

#### `t = safer.readonly(t)`

Make table read-only: block creation of new fields in this table
and setting new values to existing fields.

Note that both `safer.table` and `safer.readonly` are implemented
creating a proxy table, so:

* Equality tests will fail: `safer.readonly(t) ~= t`
* If anyone still has a reference to this table prior
  to creating the safer version, they can still mess
  with the unsafe table and affect the safe one.

About
-----

Licensed under the terms of the MIT License, the same as Lua.

During its genesis, this module was called "safe", but I renamed it
to "safer" to remind us that we are never fully safe. ;)

-- Hisham
http://hisham.hm/ - @hisham_hm