From: Bart Schaefer <schaefer@brasslantern.com>
To: zsh-users@zsh.org
Subject: Re: for loop 'bad math expression'
Date: Sat, 3 Feb 2024 20:20:44 -0800 [thread overview]
Message-ID: <CAH+w=7Y1ZMUiLxNctGcT0HbdusAThYWBzXd8UtzJDk8Hii-XFw@mail.gmail.com> (raw)
In-Reply-To: <ecf249c0-3787-463d-bc30-1440fc6b1510@app.fastmail.com>
On Sat, Feb 3, 2024 at 6:06 PM Lawrence Velázquez <larryv@zsh.org> wrote:
>
> On Sat, Feb 3, 2024, at 8:14 PM, Ray Andrews wrote:
> > 0 /usr/share/info 0 % var=abc; let var+=2; echo $var
> >
> > 2
> > ... it looks like the shell is simply throwing away 'abc' and starting
> > afresh with an integer and then incrementing it.
>
> No, that's not what happens. Within arithmetic expressions, the
> contents of variables undergo recursive arithmetic evaluation
This has been a very thorough description of the arithmetic process in
zsh, but I think misses one important detail:
% var=abc
% typeset -p var
typeset var=abc
% let var+=2
% typeset -p var
typeset var=2
Note that var has NOT acquired the "-i" (integer) attribute, despite
having been assigned a number value.
next prev parent reply other threads:[~2024-02-04 4:21 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-30 3:39 Ray Andrews
2024-01-30 3:46 ` Ray Andrews
2024-01-30 4:04 ` Bart Schaefer
2024-01-30 4:06 ` Bart Schaefer
2024-01-30 4:17 ` Ray Andrews
2024-01-30 13:44 ` Ray Andrews
2024-01-30 14:30 ` Lawrence Velázquez
2024-02-03 23:52 ` Bart Schaefer
2024-02-04 1:14 ` Ray Andrews
2024-02-04 2:05 ` Lawrence Velázquez
2024-02-04 4:20 ` Bart Schaefer [this message]
2024-02-04 16:08 ` Ray Andrews
2024-02-04 20:56 ` Lawrence Velázquez
2024-02-04 15:51 ` Ray Andrews
2024-02-04 20:48 ` Lawrence Velázquez
2024-02-04 21:09 ` Bart Schaefer
2024-02-04 21:23 ` Bart Schaefer
2024-02-05 2:10 ` Bart Schaefer
2024-02-05 2:43 ` Mikael Magnusson
2024-02-05 2:50 ` Bart Schaefer
2024-02-05 15:21 ` Ray Andrews
2024-02-05 15:48 ` Mark J. Reed
2024-02-04 14:43 ` Mark J. Reed
2024-02-04 16:37 ` Ray Andrews
2024-02-04 21:09 ` Lawrence Velázquez
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