[M3devel] Areas that may need attention in the frontend?

[Antony Hosking]

On Sep 20, 2012, at 7:37 AM, Jay K <jay.krell at cornell.edu> wrote:

> I think this isn't right. I understand the static link is implied by level > 0. But the activation/exception parameter should be always passed or never passed. Or there should be two functions -- one that takes an exception, one that doesn't, and one calls the other. Or pass it as null if there isn't an exception.
> 
> I should really not have to resort to K&R and passing varying numbers of parameters.
> 
> I still have to look at a few test cases to see when each parameter is used.
> Maybe I'm confused.
> 
> The other thing, you want the code to stay?

For now, yes.

> 
>  - Jay
> 
> 
> CC: jay.krell at cornell.edu; m3devel at elegosoft.com
> From: jay.krell at cornell.edu
> Subject: Re: [M3devel] Areas that may need attention in the frontend?
> Date: Wed, 19 Sep 2012 21:33:43 -0700
> To: hosking at cs.purdue.edu
> 
> Clarification: the "questioning comment" is not mine, it is there in the code. I suspect it is a good question & that the code isn't what it should be.
> 
>  - Jay (briefly/pocket-sized-computer-aka-phone)
> 
> On Sep 19, 2012, at 7:39 PM, Antony Hosking <hosking at cs.purdue.edu> wrote:
> 
> On Sep 19, 2012, at 9:31 PM, Jay K <jay.krell at cornell.edu> wrote:
> 
> Areas that may need attention in the frontend?
> 
> 
> TryFinStmt.m3:
> 
>       CG.Start_call_direct (p.handler.cg_proc, p.handler.level, CG.Type.Void);
>       (* Shouldn't we pass the activation parameter here?
>          What value do we pass? *)
>       CG.Call_direct (p.handler.cg_proc, CG.Type.Void);
> 
> The level let’s you compute that.
> 
> I'm wondering this too...like..what is the interface
> to except/finally blocks?
> 
> ?
> 
> It appears they take two, or one, or zero parameters,
> depending on intepretation and context.
> 
> 
> two parameters:
>  _static_link
>  exception stuff
> 
>  
> one parameter:
>  _static_link
>  
> 
> zero parameters:
>  the above
> 
> 
> I think the right implmentation (assuming no significant
> change to nested functions, which Tony is thinking about:) )
> is one parameter:
> 
>   exception stuff
> 
> and the implied/popped static_link, always.
> 
> 
> For now, I think I'll not prototype these and use K&R definitions, yuck!
> 
> That works.
> 
> Maybe generating C++ with overloads is a good idea??
> 
> 
> 
> values/Procedure.m3:
> 
>     ELSIF (cur.token = TK.tSEMI) THEN
>       t.body := NEW (Body, self := t);
>       ProcBody.Push (t.body);
>       (* try accepting the Modula-2 syntax *)
>       Error.ID (id, "expecting \'=\' before procedure body");
> 
>  
> Probably everything after the error should be removed?
> Or this is an example trying to recover from parse errors
> and doing best effort?
> 
> Yes.
> 
> 
> 
>  - Jay

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