Re: Shell Grammar man page function definition

[Oğuz]

28 Şubat 2021 Pazar tarihinde Mike Jonkmans <bashbug@jonkmans.nl> yazdı:

> Hi,
>
> The manual page says:
>         If the function reserved word is used, but the parentheses are not
> supplied,
>         the braces are required.
>
> But it seems that from all the compound commands,
> only a subshell is not possible.
>
> Some examples that work:
>         function x { :; } ## as expected
>         function x if :; then :; fi
>         function x (( 42 ))
>         function x [[ 42 ]]
>         function x for x do :; done
>         function x for (( ; 42 - 42 ; )); do :; done
>
> What does not work:
>         function x ( : )


Works fine here.

  bash-5.1$ function x ( : )
  bash-5.1$ declare -f x
  x ()
  {
      ( : )
  }


>
>
> From looking at the bash grammar I am not sure why a subshell does not
> work.
> As the subshell can be differentiated from the optional parentheses.
>
>
> Though it may be handy to disallow a subshell.
> If in the future named parameters would become a possibility.
> E.g.
>         function x (a=$1 b=$2)
>         { echo "$a$b; }
> would become ambiguous.
>
>
> Note that the Posix grammar doesn't mention the word 'function'.
> Posix does mention it, as reserved word recognized by 'some
> implementations'
> and causing undefined behavior.
>
>
> Regards, Mike Jonkmans
>
>

-- 
Oğuz