Re: Announce: Darwin module system

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

On Mon, Sep 7, 2009 at 11:00 AM, Jim Jennings wrote:
> I'll start with an example of the one Darwin function...
> structure.declare { .... }

The documentation for struct.declare defines these code fields:

   1. open={m1, ...}
   2. pre="..."
   3. files=f1 or files={f1, ...}
   4. post="..."
   5. environment="..."

When first seeing the examples, it was not obvious to me when fields
#2-5 were appropriate and how they interacted.  As I see, each of
these represents code and they are executed in sequence.  They differ,
perhaps arbitrarily, in that #3 accepts file names, but the others
accept code strings (though you could specify file names in the others
via a dofile or require, as some examples do), and only #5 handles a
return value.  Lacking #3, you can arbitrarily choose to place your
code inside #2, #4, or #5.  Would something like the following make
the model simpler and more general?

  structure.declare {
    name="test";
    open={"_G", "os"};
    environment = [[
      pre.....
      dofile '.....' .....
      post....
      return t  -- optional (return may be omitted)
    ]]
  }

or using e.g.

    environment = {[[pre.....]], '@pre2.lua', '@file1.lua',
[[post....; return t]]}

The typical purpose of #2-4 seems to be to define a module that wraps
another module, whereas the name/signature/location fields define how
that wrapped module is bound into the local namespace tree.