[ANN] stdlib 41.2.0 released

["Gary V. Vaughan" <gary@...>]

stdlib is a library of modules for common programming tasks, including
list, table and functional operations, objects, pickling, pretty-printing
and command-line option parsing.

I am happy to announce release 41.2.0 of stdlib.

stdlib's home page is at http://lua-stdlib.github.io/lua-stdlib

## Noteworthy changes in release 41.2.0 (2015-03-08) [stable]

### New features

  - New iterators, `std.npairs` and `std.rnpairs` behave like
    `std.ipairs` and `std.ripairs` resp., except that they will visit
    all integer keyed elements, including nil-valued "holes".  This is
    useful for iterating over argument lists with nils:

    ```lua
    function fn (a, b, c) for _, v in npairs {...} do print (v) end
    fn (nil, nil, 3) --> nil nil 3
    ```

  - New `debug.getfenv` and `debug.setfenv` that work with Lua 5.2 and
    5.3.

  - `debug.argscheck` will skip typecheck for `self` parameter if the
    function name specification contains a colon.

  - New `debug.resulterror` is much like `debug.argerror`, but uses the
    message format "bad result #n from 'fname'".

  - New `debug.extramsg_mismatch` to generate `extramsg` argument for
    `debug.argerror` or `debug.resulterror` on encountering a type
    mismatch.

  - New `debug.extramsg_toomany` to generate a too many arguments or
    similar `extramsg` argument.

### Deprecations

  - `debug.toomanyargmsg` has been deprecated in favour of the more
    orthogal `debug.extramsg_toomany` api.  You can rewrite clients of
    deprecated api like this:

    ```lua
    if maxn (argt) > 7 then
      argerror ("fname", 8, extramsg_toomany ("argument", 7, maxn (argt)), 2)
    end
    ```

### Bug fixes

  - `std.getmetamethod` no longer rejects non-table subjects when
    `_DEBUG.argcheck` is set.

  - `functional.bind`, `functional.collect`, `functional.compose`,
    `functional.filter` and `functional.map` propagate nil valued
    arguments correctly.

  - `functional.callable` no longer raises an argument error when passed
    a nil valued argument.

  - `debug.argcheck` and `debug.argscheck` accept "bool" as an alias for
    "boolean" consistently.

  - `io.catdir` and `io.dirname` no longer leak extra results from
    implementation details.

### Incompatible changes

  - `functional.collect` uses `std.npairs` as a default iterator rather
    than `std.ipairs`.


Install it with LuaRocks, using:

    luarocks install stdlib 41.2.0