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Date: Sat, 14 May 2011 20:09:16 +0200
Message-ID: <BANLkTimMD7_n7V-qjpYny2sx14ganaD9Zg@mail.gmail.com>
Subject: Re: Infinite recursions in math evaluation
From: Mikael Magnusson <mikachu@gmail.com>
To: Bart Schaefer <schaefer@brasslantern.com>
Cc: zsh workers <zsh-workers@zsh.org>
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On 14 May 2011 20:00, Bart Schaefer <schaefer@brasslantern.com> wrote:
> On May 14, 11:03am, Mikael Magnusson wrote:
> }
> } > "The value of $val1" in an arithmetic context is the result of doing
> } > arithmetic evaluation on whatever is stored in the parameter.  If
> } > that's the name of another (or even the same) parameter, then ...
> }
> } How did you get this from the quoted part?
>
> I did say it was implicit. :-)
>
>     At each nested level of substitution, the substituted words
>     undergo all forms of single-word substitution (i.e. not filename
>     generation), including command substitution, arithmetic expansion
>     and filename expansion
>
> In ((var)), "var" is a nested arithmetic expansion.  Inside the value
> of var, any mention of another bare parameter name is thus also a
> nested arithmetic expansion.

I can't see how this follows from the above. That whole section is
talking about multiple nested ${...} forms specifically, not nested
arithmetic expansions. I rather read the arithmetic expansion there to
mean that if you write ${$((5 + 3))} it will work, which it does. It
doesn't really say anything about what happens in arithmetic expansion
itself (does it?).

-- 
Mikael Magnusson