From: Daniel Shahaf <d.s@daniel.shahaf.name>
To: zsh-users@zsh.org
Subject: When is a pre-command assignment syntactically valid?
Date: Wed, 6 Dec 2017 23:23:05 +0000 [thread overview]
Message-ID: <20171206232305.naro27of6abrk4y3@tarpaulin.shahaf.local2> (raw)
In z-sy-h we're trying to determine in what circumstances an assignment is
valid before a command.¹
Empirically, when an assignment is followed by one of the reserved words
«((» «[[» «(» «{» «!»
a parse error results, but when an assignment is followed by the name of a
command, builtin, or function, execution succeeds. It doesn't seem to matter
whether the assigned parameter is a scalar or an array. (Of course, setting
an array in front of an external command, as in «a=(foo bar) /bin/true», isn't
necessarily _useful_ — barring 'typeset -T' and hooks — but it's syntactically
valid, which is z-sy-h's concern.)
So, I think the rule is: "reserved words may not be preceded by parameter
assignments". Is that accurate?
Thanks,
Daniel
P.S. Incidentally, I can see how it might be useful to allow assignments before
some of these constructs (e.g., «foo=bar (subshell; commands;)»), but I'm not
advocating for that; I'm just trying to grok the status quo so z-sy-h can
support it.
¹ https://github.com/zsh-users/zsh-syntax-highlighting/issues/461
next reply other threads:[~2017-12-06 23:23 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-06 23:23 Daniel Shahaf [this message]
2017-12-07 1:57 ` Bart Schaefer
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