Re: syntactic question

[Ray Andrews <rayandrews@xxxxxxxxxxx>]

On 11/21/2014 01:29 PM, Bart Schaefer wrote:
> On Nov 21, 2014 12:25 PM, "Ray Andrews" <rayandrews@xxxxxxxxxxx 
> <mailto:rayandrews@xxxxxxxxxxx>> wrote:
> >
> > I've always thought that all parsing systems work from the 'inside out'
> > which is to say that (as with math) you 'do' the deepest parenthesis
> > first, and then work outward.
>
> Quotes aren't parens, there is no left and right so you can't nest 
> them the way you are thinking of.  With only a small number of 
> exceptions, quoting in shells works left to right - once a quote is 
> open, you obey only the rules of that type of quote until it closes 
> again.  Backslashes happen to have special meaning both inside and 
> outside of quotes, but the details depend on which type of quote is 
> active.
It's one of those things that's hard to get into one's DNA.
> > In the same spirit, I'm expecting
> > the substitution to do what it does following it's own rules and
> > nevermind any quotations or anything else 'further out'.
>
> Substitution occurs if there are no quotes or inside double quotes, 
> but not inside single quotes.  The rules are different when in double 
> quotes, and documented.
Well, as long as the system works, and is understandable.  I think my 
intuitions are forgivable, even if not correct.  Bart, is there some 
readable doc that wraps it all up?  In practice I get most all my 
problems solved now, but I despair of really understanding it, I tend to 
use trial and error.