comp.lang.postscript Google Group

Re: Throwing a custom error

terry.bur...@gmail.com (Terry Burton) — Tue, 21 May 2013 14:01:08 UT

Hi Ken,

Thanks for the information. After continuing my experiments I have concluded that I do not require a non-zero exit code, so I'm not requesting the GS be modified to act in a non-standard way.

For anybody who is interested my approach, BWIPP has been modified to include a raiseerror procedure ([link]) that is invoked from the code to generate custom errors with names such as bwipp.someErrorName.

Re: Throwing a custom error

k...@spamcop.net (ken) — Mon, 20 May 2013 06:52:19 UT

In article <e4d4fc8b-af38-46db-a95e-86a88 9a0b9d1@googlegroups.com>,
terry.bur...@gmail.com says...

Essentially, you can't. By processing the error you prevent the
interpreter from 'seeing' it. So as far as the interpreter is
concerened, there is no error.

Technically this is correct, the input was fully processed in accordance

Re: Throwing a custom error

mijo...@yahoo.com (luser- -droog) — Mon, 20 May 2013 05:04:37 UT

[...]

Hopefully the ghostscript gurus will have something better,
but it might work to just use /undefined, but pack information into the undefined name itself. I know that sentence is terrible. How about an example?

...
dup type /integertype ne {
MUST_PASS_integer_TO_THIS_FUNC TION

Throwing a custom error

terry.bur...@gmail.com (Terry Burton) — Sun, 19 May 2013 02:44:25 UT

Hi,

In Barcode Writer in Pure PostScript (BWIPP) it is possible for the user to provide invalid input data. At present we do not provide any useful form of input validation or error reporting and we simply allow the code to trip up and bomb out in meaningless ways on invalid data.

To provide a somewhat uniform approach to handling invalid user input I am investigating whether the PS code could raise a custom error and terminate for each circumstance (e.g. /bwipp.badCheckDigit or /bwipp.invalidCharacter, etc) that can be communicated to the user using whatever ordinary PS error handling is available in that environment.

Re: xpost3 current challenges

mijo...@yahoo.com (luser- -droog) — Mon, 13 May 2013 04:49:17 UT

---^ should've indented this one. There's 3 tables, but 4 'variables'.

This is going to involve a bit of redesign of contexts and mfiles, as well as a cool name for the master super-duper data structure that in the darkness binds them.

But I think I'll keep itp.c pretty much as-is, and the testing main() will for now be the entry-point to the single-process interpreter. The "ghostscript"-mode, if you will. The multiprocessing stuff really needs to be a new module. So it needs a module-name, too. Going by my pattern so far, it should be a 3-letter identifier. "srv" maybe, or ... not coming up with anything else. "srv" it is!

Re: xpost3 current challenges

mijo...@yahoo.com (luser- -droog) — Sat, 11 May 2013 05:53:31 UT

On further investigation, DPS and NeWS are quite different in their precise semantics. And DPS seems simpler, so I'll start there.

DPS describes 3 ways of creating a new context:

Method 1: Private Global VM, Private Local VM

Method 2: Shared Global VM, Private Local VM

Method 3: Shared Global VM, Share Local VM

Re: xpost3 current challenges

mijo...@yahoo.com (luser- -droog) — Mon, 06 May 2013 04:39:36 UT

And NeWS implements processtype objects as magic dictionaries. So maybe that's what I should be working on. Should be pretty straightforward. dicget and dicput need to recognize a special value (object type) that refers to a getter/setter struct, something like

struct gsetter {
object (*get)(void);

xpost3 current challenges

mijo...@yahoo.com (luser- -droog) — Sun, 05 May 2013 04:59:02 UT

I've got 2 trains going at the same time here, and kinda stalled on both.

Track 1 is finishing up this postscript translation of the xpost2 scanner. It's running into issues with building procedures. And I've really painted myself into a corner with lots of code and virtually no comments. I suppose the obvious next step is to print it out and re-type it (fixing the uglies as they arise).

Re: PS-viewing Browser plugin for Windows?

mpiosucb.etlll...@att.net (tlvp) — Fri, 03 May 2013 04:28:36 UT

OK. Some web pages link to .ps files as well as to .jpg, .png, .pdf (etc.)
ones -- browsers have no trouble displaying .jpg and .pdf links -- they're
inherently capable of that -- and very little trouble with .pdf links --
there are browser add-ons (by Adobe and by others) to deal with those --

Re: PS-viewing Browser plugin for Windows?

mpiosucb.etlll...@att.net (tlvp) — Fri, 03 May 2013 04:18:09 UT

Thanks, Luuk. Not what I thought I was after -- it's an online .ps viewer,
not a browser add-on or snap-in -- but it looks interesting all the same,
and could be a good alternative choice. Cheers, -- tlvp
--
Avant de repondre, jeter la poubelle, SVP.

Re: PS-viewing Browser plugin for Windows?

l...@invalid.lan (Luuk) — Thu, 02 May 2013 18:57:16 UT

Googleing revealed this page:
[link]

•The viewer software is open source, licensed under the GNU Public License.
•Version 0.3 of the software can be downloaded .....

Re: PS-viewing Browser plugin for Windows?

zupf...@googlemail.com — Thu, 02 May 2013 11:23:38 UT

Am Mittwoch, 1. Mai 2013 22:42:03 UTC+2 schrieb tlvp:

More info about what the actual usage scenario looks like would be interesting. I.e., is it necessary to interpret PS on the client side or can it be done on the server? Why PS instead of PDF?

PostScript uploaded to Google drive can be viewed in the browser.

Re: PS-viewing Browser plugin for Windows?

mpiosucb.etlll...@att.net (tlvp) — Thu, 02 May 2013 03:21:31 UT

If you're gonna suggest spawning ghostscript, why not spawn ghostview
instead, and spare me converting to pdf and starting the Adobe plug-in?
The cs.wisc folks really not do that yet? But thanks; and cheers, -- tlvp
--
Avant de repondre, jeter la poubelle, SVP.

Re: PS-viewing Browser plugin for Windows?

jreise...@comcast.net (John Reiser) — Thu, 02 May 2013 00:04:35 UT

This is a write-your-own project. Convert to .pdf by spawning ghostscript,
then view the .pdf. Recent Firefox has a builtin .pdf viewer.

PS-viewing Browser plugin for Windows?

mpiosucb.etlll...@att.net (tlvp) — Wed, 01 May 2013 20:42:03 UT

Subject line pretty much says it all: I'm seeking a browser plugin (for FF,
or Safari or Opera or IE 7-8-9, under Windows (XP, Vista, 7)) to render .ps
files. Google, alas, steers me only to Linux or MacOS .ps browser services,
not Windows ones.

Thanks for all pointers, even dead ends :-) . Cheers, -- tlvp