Re: PATCH: sysopen (was Re: '>>' does not create file if set -C (noclobber) is active)

[Mikael Magnusson <mikachu@gmail.com>]

On Fri, Jul 24, 2015 at 1:55 PM, Peter Stephenson
<p.stephenson@samsung.com> wrote:
> Also, I suppose we should say something like...
>
> (although adding sysclose isn't necessarily a bad thing)
>
> pws
>
> diff --git a/Doc/Zsh/mod_system.yo b/Doc/Zsh/mod_system.yo
> index e4d4c31..b9b07bb 100644
> --- a/Doc/Zsh/mod_system.yo
> +++ b/Doc/Zsh/mod_system.yo
> @@ -68,6 +68,11 @@ item(tt(trunc))(
>  truncate file to size 0
>  )
>  enditem()
> +
> +To close the file, use one of the following:
> +
> +example(tt(exec {)var(fd)tt(}<&-)
> +tt(exec {)var(fd)tt(}>&-))
>  )
>  findex(sysread)
>  redef(SPACES)(0)(tt(ifztexi(NOTRANS(@ @ @ @ @ @ @ @ ))ifnztexi(        )))

I remembered this being mentioned and was looking through the docs
because I always forget where the & goes, but it looks like you never
committed it. It is mentioned in the paragraph about zsystem flock
though.

Was there a reason the new commands were not made subcommands to
zsystem? I don't see any rationale in the commit message. An advantage
would be that "zsystem supports foo" already will tell you that foo is
not a recognized subcommand. We could add the sysopen/tell/close/seek
commands to zsystem supports anyway, even though they're not
subcommands.

> One very minor comment now I've tried this:
>
> % sysread -i fd
> sysread: integer expected: fd
>
> I think it would probably be appropriate and consistent with other
> similar contexts for this to do matn eval, even though the workaround is
> obvious and trivial.

I feel like this might be slightly dangerous, as if you get used to fd
being treated as an integer here, you may try sysopen -u fd and it
will silently use another fd and assign to your parameter instead.


It also looks like the -u option for sysopen is not optional, so it
shouldn't be listed in [ ].

--- i/Doc/Zsh/mod_system.yo
+++ w/Doc/Zsh/mod_system.yo
@@ -31,7 +31,7 @@ not recognised (no message is printed for this).
 findex(sysopen)
 redef(SPACES)(0)(tt(ifztexi(NOTRANS(@ @ @ @ @ @ @ @ ))ifnztexi(        )))
 xitem(tt(sysopen) [ tt(-arw) ] [ tt(-m) var(permissions) ] [ tt(-o)
var(options) ])
-item(SPACES()[ tt(-u) var(fd) ] var(file))(
+item(SPACES()tt(-u) var(fd) var(file))(
 This command opens a file. The tt(-r), tt(-w) and tt(-a) flags indicate
 whether the file should be opened for reading, writing and appending,
 respectively. The tt(-m) option allows the initial permissions to use when


-- 
Mikael Magnusson