[erlang-questions] newbie: why c.erl is special?

[Anthony Kong]

Hi, Shiwei,

I'd concur that a capability to alias an imported module sounds like
an attractive idea.

I personally would prefer a new directive called "import_as".

======
-module(lists). %% I want to call my module lists too.
-import_as(lists, stdlib_lists).

...
lists:copycat() ->
  stdlib_lists:reverse([a,b,c]). %% essentially calling lists:reverse([a,b,c])

======

Just the same as your idea of "-alias".

Until then, I probably have to learn to live in this namespace flatland :-)

Cheers, Anthony



2008/3/1 shiwei xu <xushiweizh@REDACTED>:
> I think flat module namespaces is a defect of erlang design.
>
> For example, I write a foo.erl, It works well. But maybe in a late erlang
> version (eg. R13B)  also write such  module named  foo.erl. Then,  you can
> see  my application goes wrong.
>
> How to avoid things like this? Let's see the following ways:
>
> 1. Adjust module searching paths, and let user path (which contains my
> foo.erl) take precedence over erlang stdlib/otp path. But, this way can't
> always work well. If some other stdlib/otp modules use system foo.erl (not
> my foo.erl), Things goes wrong.
>
> 2. Write erlang modules always named with a prefix (a fake namespace. For
> example, projectname_foo.erl or organization_projectname_foo
> .erl). This way really can solve the problem. But, It seems ugly.
>
> Is there a way let's user still can call foo:func (not call foo.erl provied
> by stdlib/otp, but my projectname_foo.erl)? I have a suggestion:
>
> Can erlang provide a 'module name alias'? That is, I can rename a module's
> name temporarily in a module? For example:
>
> -module(a_module_that_call_my_foo).
> -alias(foo, organization_projectname_foo). %% alias
>
> some_func_call_foo() ->
>     foo:func().  %% same as: organization_projectname_foo:func()
>
> Currently I can do this by using the 'define' keyword. For example:
>
> -module(a_module_that_call_my_foo).
>  -define(FOO, organization_projectname_foo). %% alias
>
> some_func_call_foo() ->
>     ?FOO:func().
>
> It works well, but a bit ugly.
>
>
>
> On Sat, Mar 1, 2008 at 6:51 AM, Matt Stancliff <sysop@REDACTED> wrote:
>
> >
> >
> >
> >
> >
> > On Feb 29, 2008, at 14:34, Anthony Kong wrote:
> >
> > > If I rename c.erl to something else, the problem goes away.
> > >
> > > What is special about "-module(c)" ?
> >
> >   Welcome to the world of flat module namespaces.
> >
> >   The code module is your friend in these circumstances.
> >   Look into code:clash() and code:which(module).
> >
> >   code:which(c) should return "<base path>/lib/erlang/lib/stdlib-
> > <ver>/ebin/c.beam"
> >
> >
> > -Matt
> > --
> > Matt Stancliff            sysop@REDACTED
> > AIM: seijimr              iPhone: 678-591-9337
> > "The best way to predict the future is to invent it." --Alan Kay
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> > erlang-questions mailing list
> > erlang-questions@REDACTED
> > http://www.erlang.org/mailman/listinfo/erlang-questions
> >
>
>
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