proposal: executing modules as scripts

[David Manura <dm.lua@...>]

New feature proposal for Lua: Module Execution Proposal

=== Abstract ===

This is a proposal for a new command-line switch (-p) that loads a function with
the given package name via the searchers in package.loaded and then executes
that function as a script, passing the command-line arguments to the function as
arguments.

    lua -p modname args

Example:

    -- my/app.lua
    print("hello", io.read"*a", ...)
    local i=0; while arg[i] do print(i, arg[i]); i=i-1 end

    $ echo -n 123 | lua -p my.app 3 4 5
    hello   123     3       4       5
    0       my.app
    -1      -p
    -2      lua

=== Rationale ===

A typical use of this would be if you have a Lua script installed in the Lua
path (e.g. LUA_PATH) rather than the system PATH, and you want to locate and
execute that script. The script may have a dual use as a module and a
command-line utility. Maybe this is a Lua-based profiler, debugger, code
validator, or macro processor that operates on other Lua code.

    lua -p yet.another.debugger mybuggyprogram.lua 3 4 5

    lua -p yet.another.preprocessor myprogram.m4 4 5 5

There is precedent here--for example, the "-m" switch in Python:

    -m mod : run library module as a script (terminates option list)

-----

The full details and patch for this proposal are available at

  http://lua-users.org/wiki/ModuleExecutionProposal

The description currently also suggests a new "loadmodule" function and includes
three related proposals:

  - Allow -e to Accept Command Arguments
  - New package.find Function
  - Detecting Whether Function Loaded via Require

Comments?