[Oberon] FPGA - Pictures.Mod composition

[Jörg]

Tomas

Good coding practice in Oberon (-2 or -07) is:
   "Split creation (NEW) from initialization"

As Chris mentioned reason is described in
http://ssw.jku.at/Research/Books/Oberon2.pdf chapter 8.1

I would call the procedures not "New" and "New2" but rather "InitBitmap" and
"InitPicture" or "InitBM" and "InitPic" if you prefer shorter names :-)

br
Jörg

-----Original Message-----
From: Oberon [mailto:oberon-bounces at lists.inf.ethz.ch] On Behalf Of Tomas
Kral
Sent: Monday, October 02, 2017 12:37 PM
To: oberon at lists.inf.ethz.ch
Subject: Re: [Oberon] FPGA - Pictures.Mod composition

On Sun, 1 Oct 2017 20:23:21 +0200
August Karlstrom <fusionfile at gmail.com> wrote:

> common approach is to separate memory allocation 
> and initialization

Hi,

I would know the reason for separating. As FPGA { Oberon-07, V5 } is
about building system from scratch while making it simple, we could
possibly also experiment with new tricks here. I have therefore merged
these procedures into one.

> PROCEDURE Bitmaps.New(w, h, dpt) : Bitmaps;
> PROCEDURE Bitmaps.New2(B: Bitmap; w, h, dpt) : Bitmaps;


PROCEDURE New*(B: Bitmap; w, h, dpt: INTEGER) : Bitmap;
BEGIN
  IF B = NIL THEN NEW(B) END; (* create itself *)
  IF B # NIL THEN             (* initialise itself *)
    (* ... *)                 (* allocate itself *)
  END
RETURN B END New;


VAR b: Bitmap; p: Picture
b := Bitmaps.New(NIL, w, h, 1); (* creating bitmap *)
NEW(b); Bitmaps.New(b, w, h, 1); (* also creating bitmap *)
NEW(p); b := Bitmaps.New(p, w, h, 1); (* creating picture *)

Seems simple, does the job, bad idea?

-- 
Tomas Kral <thomas.kral at email.cz>
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