References: <53EA540E DOT 9000609 AT sonic DOT net>
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Date: Tue, 12 Aug 2014 13:49:39 -0700
From: Cirilo Bernardo <cirilo_bernardo AT yahoo DOT com>
Subject: Re: [geda-user] rs-274x nits
To: "geda-user AT delorie DOT com" <geda-user AT delorie DOT com>
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----- Original Message -----

> From: Dave Curtis <davecurtis AT sonic DOT net>
> To: geda-user AT delorie DOT com
> Cc: 
> Sent: Wednesday, August 13, 2014 3:51 AM
> Subject: [geda-user] rs-274x nits
> 
> I'm trying to interpret the gerber format specification document 
> authored by Ucamco.
> 
> 1. On page 35 it says:
> The line separators CR and LF have no effect; they can be ignored when 
> processing the file. It
> is recommended to use line separators to improve human readability.
> 
> 2. On page 36 it says:
> It is recommended to add line separators between data blocks for 
> readability. Do not
> put a line separator within a data block, except after a comma separator 
> in long data blocks.
> The line separators have no effect on the image.
> 
> 
> 3. on page 40, talking about closing parameter blocks it says:
> The ‘%’ must immediately follow the ‘*’ of the last data block without 
> intervening line separators.
> This is an exception to the general rule that a data block can be 
> followed by a line separator.
> 
> #3 is clear enough.
> 
> #1 and #2 seem to be in conflict.  A strict reading of #1 would say that 
> CR and LF should simply be expunged, and that CR/LF could even split 
> G-coded, numbers, etc., like this:
> G
> 03
> X
> 123
> *
> Which seems odd, but is a result of strict reading of #1.   But is in 
> conflict with the advice of #2.
> 
> It's easy enough to comply with the advice of #2 while writing.  But if 
> reading RS-274X, should CR/LF's that split lexical units be ignored? 
> Although I realize that even if legal, I doubt if anyone writes gerber 
> that way.
> 
> -dave
> 

There is no conflict at all:

1. The CR/LF are optional; you do not need them but they are recommended
to make the file look better to humans.

2. If you use CR/LF to make a data block look prettier, you can only use
CR/LF after a comma.

- Cirilo