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The first line of PostScript programs

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  The first line of PostScript programs jdaw1 <jdawiseman@gmail.com> - 2014-12-17 13:20 -0800
    Re: The first line of PostScript programs rodd@panix.com (Rod Dorman) - 2014-12-17 23:06 +0000
      Re: The first line of PostScript programs jdaw1 <jdawiseman@gmail.com> - 2014-12-18 05:13 -0800
        Re: The first line of PostScript programs ken <ken@spamcop.net> - 2014-12-18 13:32 +0000
          Re: The first line of PostScript programs jdaw1 <jdawiseman@gmail.com> - 2014-12-18 06:02 -0800
            Re: The first line of PostScript programs ken <ken@spamcop.net> - 2014-12-18 15:49 +0000
        Re: The first line of PostScript programs rodd@panix.com (Rod Dorman) - 2014-12-18 17:30 +0000
          Re: The first line of PostScript programs jdaw1 <jdawiseman@gmail.com> - 2014-12-18 13:00 -0800
            Re: The first line of PostScript programs "twenty-six@b-mint.net" <twenty-six@b-mint.net> - 2014-12-19 07:45 +0000
              Re: The first line of PostScript programs ken <ken@spamcop.net> - 2014-12-19 07:53 +0000
            Re: The first line of PostScript programs ken <ken@spamcop.net> - 2014-12-19 07:53 +0000

#2119 — The first line of PostScript programs

What is the first line of your PostScript programs? What should mine be? 

For a program written in language level 2, not obeying document structuring conventions, what should it be? I've always used "%!". Should it be "%!PS-Adobe-2.0"? Or would that promise document structuring conventions? 

(This was erroneously posted in adobe.postscript.programming: hereby reposted in comp.lang.postscript.)

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#2120

In article <3aa025db-52a4-4c51-a30e-212c88672407@googlegroups.com>,
jdaw1  <jdawiseman@gmail.com> wrote:
>What is the first line of your PostScript programs? What should mine be? 
>
>For a program written in language level 2, not obeying document
>structuring conventions, what should it be? I've always used "%!".

That's fine, I generally use "%!PS"

> Should it be "%!PS-Adobe-2.0"? Or would that promise document
> structuring conventions?

That declares that it's a DSC version 2.0 conforming document. It's
bad form to claim that when it isn't conforming.

-- 
					-- Rod --
rodd(at)polylogics(dot)com

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#2121

Thank you. 

> It's bad form to claim that when it isn't conforming. 

I want to claim as much as possible of what is true, but definitely no more than that. 


please, is there a published standard, or at least a published convention that functions as a standard? 

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#2122

In article <b6fbeb62-31e7-4784-b46e-70c7be8e44f8@googlegroups.com>, 
jdawiseman@gmail.com says...
> 
> Thank you. 
> 
> > It's bad form to claim that when it isn't conforming. 
> 
> I want to claim as much as possible of what is true, but definitely no more than that. 
> 
> 
> please, is there a published standard, or at least a published convention that functions as a standard? 

The PostScreipt Language Reference Manual has some information on page 
801 and 802:

"PostScript programs that have the notation %!PS-Adobe-3.0 as the first 
line of the file are considered to be regular page descriptions that 
conform to the document structuring conventions (DSC) version 3.0. See 
Adobe Technical Note #5001, PostScript Language Document Structuring 
Conventions Specification, for more information about DSC conformance 
and conventions. There is no requirement that a regular page description 
conform to DSC, but it is strongly recommended."

Other than that it is conventional to put %! as the first 2 bytes of a 
PostScript program, but it is not a requirement, nor is it documented 
anywhere, its simply that PostScript programmers generally do, even for 
non-DSC programs.

Some people put %!PS but that's not required either, it does allow you 
to differentiate PostScript and PDF though.

If you do put a full DSC line, then you should be sure that your program 
conforms to DSC (as already mentioned by Tod Dorman) as PostScript 
processors (as opposed to interpreters) may make assumptions about the 
content of the PostScript program if you say that it is DSC-compliant.


		Ken

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#2123

Thank you. 

PLRM3 doesn't say whether "%!PS-Adobe-2.0" implies DSC. Do you know it does, or is that deduced (assumed) by analogy? 

Anyway, I'm persuaded to use "%!PS".

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#2124

In article <e45e77bc-62a0-4f07-a37c-d29f18142ecd@googlegroups.com>, 
jdawiseman@gmail.com says...
> 
> Thank you. 
> 
> PLRM3 doesn't say whether "%!PS-Adobe-2.0" implies DSC. Do you know it does, or is that deduced (assumed) by analogy? 

It means DSC 2.0, the trailing numbers are the DSC version. I think 
that's documented in the DSC tech note.

Indeed quickly chcking the tech note makes it clear this is the case.

 Note that technically this isn't quite what the spec says. It says that 
the presence of the string "%!PS-Adobe-3.0" means its a DSC 3.0 
conforming file, and that "PS-Adobe-2.1" was a DSC 2.1 conforming file. 
It doesn't actually *say* that the version number is encoded as part of 
the string. In practice this is irrelevant, there are only Adobe DSC 
versions documented.

 
> Anyway, I'm persuaded to use "%!PS".

I would :-)

		Ken

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#2125

In article <b6fbeb62-31e7-4784-b46e-70c7be8e44f8@googlegroups.com>,
jdaw1  <jdawiseman@gmail.com> wrote:
>Thank you. 
>
>> It's bad form to claim that when it isn't conforming. 
>
>I want to claim as much as possible of what is true, but definitely no
>more than that. 
>>
>please, is there a published standard, or at least a published
>convention that functions as a standard? 

PostScript Language Document Structuring Conventions Specification
http://partners.adobe.com/public/developer/en/ps/5001.DSC_Spec.pdf

3.1 Conforming Documents
A conforming document can expect to receive the maximum amount of
services from any document manager. A conforming document is recognized
by the header comment %!PS-Adobe-3.0 and is optionally followed by
keywords indicating the type of document.

3.2 Non-Conforming Documents
A non-conforming document is recognized by the %! header comment.
Under no circumstances should a non-conforming document use the
%!PS-Adobe-3.0 header comment.

-- 
					-- Rod --
rodd(at)polylogics(dot)com

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#2126

My document is a program: it computes the number of pages of output, which are generated within nested for/forall loops. So it is definitely non-conforming. 

Does "%!PS" promise anything more specific than PostScript?

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#2127

On 18/12/2014 21:00, jdaw1 wrote:
> My document is a program: it computes the number of pages of output, which are generated within nested for/forall loops. So it is definitely non-conforming.
>
> Does "%!PS" promise anything more specific than PostScript?
>
Is there a "validator" that can say if my Postscript is conforming to 
DSC or not?

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#2129

In article <5493d7b5$0$46489$c3e8da3$9b4ff22a@news.astraweb.com>, 
twenty-six@b-mint.net says...
> 
> On 18/12/2014 21:00, jdaw1 wrote:
> > My document is a program: it computes the number of pages of output, which are generated within nested for/forall loops. So it is definitely non-conforming.
> >
> > Does "%!PS" promise anything more specific than PostScript?
> >
> Is there a "validator" that can say if my Postscript is conforming to 
> DSC or not?


I've never heard of one. It woudl be difficult to verify some of the 
conditions programmatically.

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#2128

In article <b9c180d8-eaa2-4224-90a9-67b4f038fe78@googlegroups.com>, 
jdawiseman@gmail.com says...
> 
> My document is a program: it computes the number of pages of output, which are generated within nested for/forall loops. So it is definitely non-conforming. 
> 
> Does "%!PS" promise anything more specific than PostScript?

No.

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