From: Bart Schaefer <schaefer@brasslantern.com>
To: Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: Defining function based on alias
Date: Sun, 8 Jan 2017 12:14:54 -0800 [thread overview]
Message-ID: <170108121454.ZM10678@torch.brasslantern.com> (raw)
In-Reply-To: <20170108191922.3d3de59f@ntlworld.com>
On Jan 8, 7:19pm, Peter Stephenson wrote:
} Subject: Re: Defining function based on alias
}
} I am about to commit the following, which I hope will hope will stop
} people coming to grief with this common confusion. Please say if you
} see any problems.
No problems, but -- if it's possible to detect this situation, why not
simply suppress the alias expansion and define the function as named,
rather than trigger an error?
Etc/FAQ should be updated too.
I never remember how to rebuild FAQ from FAQ.yo ... can someone check
my yodl syntax?
diff --git a/Etc/FAQ.yo b/Etc/FAQ.yo
index 6b635ea..9eb23db 100644
--- a/Etc/FAQ.yo
+++ b/Etc/FAQ.yo
@@ -574,7 +574,8 @@ tt(EXTENDED_GLOB).
it() Aliases and functions:
itemize(
it() The order in which aliases and functions are defined is significant:
- function definitions with () expand aliases -- see question \
+ in zsh versions 5.3.1 and earlier, function definitions with ()
+ expand aliases -- see question \
link(2.3)(23).
it() Aliases and functions cannot be exported.
it() There are no tracked aliases: command hashing replaces these.
@@ -704,6 +705,12 @@ label(23)
the manual). Note also that the mytt(;) at the end of the function is
optional in zsh, but not in ksh or sh (for sh's where it exists).
+ Recent versions of zsh support anonymous functions with argument lists,
+ so you can create an alias that acts like a function.
+ verb(
+ alias cd='() { builtin cd "$@"; print -D $PWD; }'
+ )
+
Here is Bart Schaefer's guide to converting csh aliases for zsh.
enumerate(
@@ -711,6 +718,9 @@ label(23)
then in zsh you need a function (referencing tt($1), tt($*) etc.).
Otherwise, you can use a zsh alias.
+ In zsh version 5.0 and later you can use an anonymous zsh function in
+ combination with a zsh alias.
+
myeit() If you use a zsh function, you need to refer _at_least_ to
tt($*) in the body (inside the tt({ })). Parameters don't magically
appear inside the tt({ }) the way they get appended to an alias.
@@ -772,13 +782,17 @@ label(23)
alias l='/bin/ls -F'
l() { /bin/ls -la "$@" | more }
)
- mytt(l) in the function definition is in command position and is expanded
+ mytt(l) in the function definition is in command position and may expand
as an alias, defining mytt(/bin/ls) and mytt(-F) as functions which call
mytt(/bin/ls), which gets a bit recursive. This can be avoided if you use
- mytt(function) to define a function, which doesn't expand aliases. It is
- possible to argue for extra warnings somewhere in this mess.
+ mytt(function) to define a function, which doesn't expand aliases.
+
+ For zsh versions after 5.3.1, alias expansion of function names is an
+ error by default and the option tt(ALIAS_FUNC_DEF) must be active to
+ expand aliases in function names. However, this option em(is) active
+ in compatibility modes where aliases are supported.
- One workaround for this is to use the "function" keyword instead:
+ Here is an example using the "function" keyword instead:
verb(
alias l='/bin/ls -F'
function l { /bin/ls -la "$@" | more }
next prev parent reply other threads:[~2017-01-08 20:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-07 22:16 Peter Stephenson
2017-01-08 19:19 ` Peter Stephenson
2017-01-08 20:14 ` Bart Schaefer [this message]
2017-01-08 20:23 ` Peter Stephenson
2017-01-09 0:09 ` Bart Schaefer
2017-01-09 4:02 ` Daniel Shahaf
2017-01-09 10:33 ` Peter Stephenson
2017-01-09 1:55 ` Daniel Shahaf
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