How to show zsh function definition (like bash “type myfunc”)?

问题

How do I show the definition of a function in zsh? type foo doesn't give the definition.

In bash:

bash$ function foo() { echo hello; }

bash$ foo
hello

bash$ type foo
foo is a function
foo () 
{ 
    echo hello
}

In zsh:

zsh$ function foo() { echo hello; }

zsh$ foo
hello

zsh$ type foo
foo is a shell function

回答1:

The zsh idiom is whence, the -f flag prints function definitions:

zsh$ whence -f foo
foo () {
    echo hello
}
zsh$

In zsh, type is defined as equivalent to whence -v, so you can continue to use type, but you'll need to use the -f argument:

zsh$ type -f foo
foo () {
    echo hello
}
zsh$

And, finally, in zsh which is defined as equivalent to whence -c - print results in csh-like format, so which foo will yield the same results.

man zshbuiltins for all of this.

回答2:

I've always just used which for this.

回答3:

tl;dr

declare -f foo  # works in zsh and bash

typeset -f foo  # works in zsh, bash, and ksh

type -f / whence -f / which are suboptimal in this case, because their purpose is to report the command form with the highest precedence that happens to be defined by that name (unless you also specify -a, in which case all command forms are reported) - as opposed to specifically reporting on the operand as a function.

The -f option doesn't change that - it only includes shell functions in the lookup.

Aliases and shell keywords have higher precedence than shell functions, so, in the case at hand, if an alias foo were also defined, type -f foo would report the alias definition.

Note that zsh does expand aliases in scripts by default (as does ksh, but not bash), and even if you turn alias expansion off first, type -f / whence -f / which still report aliases first.